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Phylogenetic networks form partial trees

Phylogenetic networks form partial trees
Phylogenetic networks form partial trees

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Phylogenetic Networks from Partial Trees S.Gr¨u newald Department of Combinatorics and Geometry (DCG),CAS-MPG Partner Institute for Computational Biology (PICB),Shanghai Institutes for Biological Sciences (SIBS),Chinese Academy of Sciences (CAS),China,and K.T.Huber and Q.Wu School of Computing Sciences,University of East Anglia,Norwich,NR57TJ,United Kingdom.February 1,2008

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K.T.Huber

School of Computing Sciences,

University of East Anglia,

Norwich,NR57TJ,

United Kingdom.

email:katharina.huber@https://www.doczj.com/doc/b812298092.html,

FAX:+44(0)1603593345

We would prefer to submit the?nal manuscript in LATEX.

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Abstract

A contemporary and fundamental problem faced by many evolu-

tionary biologists is how to puzzle together a collection P of partial

trees(leaf-labelled trees whose leaves are bijectively labelled by species

or,more generally,taxa,each supported by e.g.a gene)into an overall

parental structure that displays all trees in P.This already di?cult

problem is complicated by the fact that the trees in P regularly sup-

port con?icting phylogenetic relationships and are not on the same

but only overlapping taxa sets.A desirable requirement on the sought

after parental structure therefore is that it can accommodate the ob-

served con?icts.Phylogenetic networks are a popular tool capable

of doing precisely this.However,not much is known about how to

construct such networks from partial trees,a notable exception being

the Z-closure super-network approach and the recently introduced Q-

imputation approach.Here,we propose the usage of closure rules to

obtain such a network.In particular,we introduce the novel Y-closure

rule and show that this rule on its own or in combination with one

of Meacham’s closure rules(which we call the M-rule)has some very

desirable theoretical properties.In addition,we use the M-and Y-rule

to explore the dependency of Rivera et al.’s“ring of life”on the fact

that the underpinning phylogenetic trees are all on the same data set.

Our analysis culminates in the presentation of a collection of induced

subtrees from which this ring can be reconstructed.

1Introduction

Phylogenetic trees have proved an important tool for representing evolution-ary relationships.For a set X of species(or,more generally,taxa)these are formally de?ned as leaf-labelled trees whose leaves are bijectively labelled by the elements of X.Advances in DNA sequencing have resulted in ever more data on which such trees may be https://www.doczj.com/doc/b812298092.html,putational limitations however combined with the need to understand species evolution have left biologists with the following fundamental problem which we will refer to as amalgamation problem:given a collection P of phylogenetic trees,how can these trees be amalgamated into an overall parental structure that preserves the phylogenetic relationships supported by the trees in P?The hope is that such a structure might help shed light on the evolution of the underlying genomes(and thus the species).

In the ideal case that all trees in P support the same phylogenetic rela-tionships(as is the case for trees T1and T2depicted in Fig.1)this structure is known to be a phylogenetic tree and a supertree method[2]may be used to reconstruct it.For the above example the outcome T?of such a method is

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T2

T1

Figure1:3phylogenetic trees which appeared in weighted form in[17]on subsets of the7plant species: A.thaliana(A.th),A.suecia(A.su),Turri-tis(Tu)A.arenosa(A.ar),A.cebennensis(A.ce),Crucihimalaya(Cru)and A.halleri(A.ha).

T1with species Cru(see Fig.1for full species names)attached via a pendant edge to the vertex labelled v.It should be noted that T?supports the same phylogenetic relationships as T1and T2in the following sense:For a?nite set X,call a bipartition S={A, A}of some subset X′?X a partial split on X,or a partial(X)-split for short,and denote it by A| A or,equivalently,by A|A where A:=X′?A.In particular,call S a(full)split of X if X′=X. Furthermore,say that a partial X-split S=A| A extends a partial X-split S′=B| B if either B?A and B? A or B? A and A? B.Finally,say that a phylogenetic tree T displays a split S=A| A if S is a partial split on the leaf set L(T)of T induced by deleting an edge of T.Then“supports the same phylogenetic relationships”means that for every split S displayed by T1or T2there exists a split on L(T?)that extends S and is displayed by T?.

Due to complex evolutionary mechanisms such as incomplete lineage sorting,recombination(in the case of viruses),or lateral gene transfer(in case of bacteria)the trees in P may however support not the same but con?icting phylogenetic relationships.A phylogenetic network in the form of a split network(see[10,19]for overviews)rather than a phylogenetic tree is therefore the structure of choice if one wishes to simultaneously represent all phylogenetic relationships supported by the trees in P.An example in point is the split network pictured in Fig.2which appeared as a weighted network in[17].With replacing“edge”in the de?nition of displaying by “band of parallel edges”and“L(T)”by“set of network vertices of degree 1”to obtain a de?nition for when a split network displays a split,it is straight forward to check that the network in Fig.2displays all splits displayed by the3trees pictured in Fig.1.

It should be noted that phylogenetic networks such as the one depicted in

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Fig.2(see e.g.[7,11,14]for recently introduced other types of phylogenetic

networks)provide a means to visualize the complexity of a data set and

should not be thought of as an explicit model of evolution.Awareness of

this complexity does not only allow the exploration of a data set but,as is the case of e.g.hybridization networks[14],can also serve as starting point

for obtaining an explicit model of evolution(see[12]for more on this).

Figure2:A circular phylogenetic network that represents all phylogenetic relationships supported by the trees depicted in Fig.1(see that?gure for

full species names).

Apart from displaying all splits induced by the3trees depicted in Fig.1,

the network depicted in Fig.2has a further interesting feature.It is cir-

cular.In other words,if X denotes the set of the7plant species under

consideration,then the elements of X can be arranged around a circle C so

that every split S=A| A of X displayed by the network can be obtained by intersecting C with a straight line so that the label set of one of the resulting

2connected components is A and the label set of the other is A.

Although seemingly a very special type of phylogenetic network,circular

phylogenetic networks are a frequently used structure in phylogenetics(see

e.g.[3,4,5,6,8])as they do not only naturally generalize the concept of a

phylogenetic tree but are also guaranteed to be representable in the plane;a fact that greatly facilitates drawing and thus analyzing them.However,al-though recently?rst steps have been made with regards to?nding a solution to the amalgamation problem in terms of a phylogenetic network leading to the attractive Z-closure[13]and Q-imputation[9]approaches,very little is known about a solution of this problem in terms of a circular phylogenetic network.

Intrigued by this and motivated by the fact that,from a combinatorial

point of view,phylogenetic trees and networks are split systems(i.e.collections

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of full splits)and that therefore the amalgamation problem boils down to the problem of how to extend partial splits on some set X to splits on X,we wondered whether closure rules for partial splits could not be of help.Es-sentially mechanisms for splits’enlargement,such rules have proved useful for supertree construction and also underpin the above mentioned Z-closure super-network approach.As it turns out,this is indeed the case.As an immediate consequence of our main result(Corollary5.5),we obtain that for a collection of partial splits that can be“displayed”by a circular phy-logenetic network N,the collection of(full)splits generated by the closure rules in the centre of this paper is guaranteed to be displayable by N and also independent of the order in which the rules are applied.

In a study aimed at shedding light into the origin of eukaryotes,Rivera et al.[20]put forward the idea of a“ring of life”with the eukaryotic genome being the result of a fusion of two diverse procaryotic genomes(see also [16,20,23]).A natural and interesting question in this context is how dependent Rivera et al.’s ring of life is on the fact that all underpinning trees are on the same taxa set.In the last section of this paper,we provide a partial answer by presenting an example of a collection of induced partial trees from which the ring of life can be reconstructed using the M-and Y-rule.

The paper is organized as follows.In Section2,we?rst introduce some more terminology and then restate one of Meacham’s closure rules(our M-rule)and introduce the novel Y-rule.In Section3,we study the relationship between the M-and Y-rule and the closure rule that underpins the afore-mentioned Z-closure super-network approach.In Section4,we introduce the concept of a circular collection of partial splits and show that both the Y-and M-rule preserve circularity(Proposition4.4).In Section5,we in-troduce the concept of a split closure and show that for certain collections of partial splits this closure is independent of the order in which the Y-rule and/or M-rule are/is applied(Theorem5.3).This result lies at the heart of Corollary5.5.In Section6,we explore the dependency of Rivera et al.’s ring of life on the fact that the underpinning trees are all on the same data set

Throughout the paper,X denotes a?nite set and the terminology and notation largely follows[21].

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2Closure rules

We start this section by introducing some additional terminology and nota-tion.Subsequent to this,we?rst restate Meacham’s rule(which we call the M-rule)and then introduce a novel closure rule which we call the Y-rule.

LetΣ(X)denote the collection of all partial splits of X and suppose Σ?Σ(X).Then a partial split S∈Σthat can be extended by a partial split S′∈Σ?S is called redundant.The set obtained by removing redundant elements fromΣis denoted byΣ?.IfΣ=Σ?thenΣis called irreducible and the set of all irreducible subsets inΣ(X)is denoted by P(X).Note that the relation“ ”de?ned for any two(partial)split collectionsΣ,Σ′∈P(X) by puttingΣ Σ′if every partial split inΣis extended by a partial split in Σ′is a partial order on P(X)[21].

Suppose for the following thatθis a closure rule,that is,a replacement rule that replaces a collection A?Σ(X)of partial splits that satisfy some condition Cθby a collectionθ(A)?Σ(X)whose elements are generated in some systematic way from the partial splits in A(see e.g.the M-and the Y-closure rules presented below for two such systematic ways).Suppose Σ,Σ′∈P(X)are two irreducible collections of partial splits and Cθ(Σ)is the set of all subsets ofΣthat satisfy Cθ.If there exists some subset A∈Cθ(Σ) such thatΣ′=(Σ∪θ(A))?then we say thatΣ′is obtained fromΣvia a single application ofθ.Finally,if for every subset A∈Cθ(Σ)we have θ(A)? Σthen we call an application ofθtoΣtrivial and say thatΣis closed with respect toθ.

We are now in the position to present the2closure rules we are mostly concerned with in this paper:the M-rule which is originally due to Meacham [18]and the novel Y-rule.We start with Meacham’s rule.

2.1The M-rule

Suppose S1,S2∈Σ(X)are two distinct partial splits of X.Then the M-rule θM is as follows:

(θM)If there exists some A i∈S i,i=1,2such that

A1∩A2=?and A1∩ A2=?(1)

then replace A={S1,S2}by the setθ{A1,A2}

M (A)which comprises of

A and,in addition,also the partial splits

S′1=(A1∩A2)|( A1∪ A2)and S′2=( A1∩ A2)|(A1∪A2).

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In case the partial splits S1and S2are such that there is no ambiguity with regards to the identity of the sets A1and A2in the statement of the M-rule or

they are irrelevant to the discussion,we will simplifyθ{A1,A2}

M (A)toθM(A).

Clearly,such ambiguity cannot arise if S1and S2are compatible,that is, there exist subsets D i∈S i,i=1,2such that D1∩D2=?.However if S1 and S2are incompatible,that is,not compatible then caution is required.

Note that if A1and A2as in the statement of the M-rule are such that A2?A1and A1? A2,then it is easy to verify thatθM applies trivially to A.Also note that for anyΣ∈P(X)and any two distinct partial splits

S1,S2∈Σ,we have

Σ (Σ∪θM({S1,S2}))?.

Finally,note that any phylogenetic tree on X that displays the partial splits

in some setΣ∈P(X)also displays the partial splits in(Σ∪θM({S1,S2}))?,

S1,S2∈Σ.

2.2The Y-rule

Suppose S i∈Σ(X),i=1,2,3,are three distinct partial splits of X.Then the Y-ruleθY is as follows:

(θY)If there exists some A i∈S i,i=1,2,3such that

?∈{A1∩A2∩A3, A1∩ A2∩A3, A1∩A2∩ A3}and

A1∩ A2∩ A3=?.(2) (see Fig.3(a)for a graphical interpretation),then replace A={S1,S2,S3}

by the setθ{A1,A2,A3}

Y

(A)which comprises of the partial splits

S′1= A1∪( A2∩ A3)|A1,S′2=A2∪(A1∩ A3)| A2,and

S′3=A3∪(A1∩ A2)| A3.

Although the condition in(2)might look quite strange at?rst sight,the class of triplets of partial splits that satisfy it is very rich.For example,sup-pose that S i=A i| A i,i=1,2,3are splits of X that can be arranged in the plane as indicated in Fig.3(b)where each bold,straight line represents one

of S i,i=1,2,3and the dots represent non-empty triplewise intersections

of the parts of S i,i=1,2,3,in which they lie.For example,the dot in the bottom wedge represents the intersection A1∩A2∩A3.The shaded regions correspond to the3non-empty intersections mentioned in the statement of the Y-rule.The partial splits S′i=A′i| A′i i=1,2,3obtained by restricting

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1

1

1

1

1

1

1

10

1

1

1

1

A12∩A3=?

(a)

A1∩A2∩ A3=?

A1∩ A2∩ A1∩A2∩ A3=?

A1

(b)

A2

A3

A3A1

A2

Figure3:(a)A graphical representation of Condition(2)in the form of a Y.

(b)An example of three splits,depicted in bold lines,that satisfy Condition

(2)–see text for details.

S1,S2,and S3to di?erent subsets of X so that the shaded regions remain non-empty form a triplet of partial splits that satisfy(2).

As the example of set A comprising the three partial splits S1=145|2367, S2=1357|246,and S3=127|356shows di?erent choices of the sets A i,

i=1,2,3lead to di?erent setsθ{A1,A2,A3}

Y

(A).For example,if A1:= {1,4,5},A2:={1,3,5,7},and A3:={1,2,7}then(2)is satis?ed and

θ{A1,A2,A3}

Y

(A)={S1,S2,1247|356}.If however A1and A2are as before

and A3:={3,5,6},then(2)is also satis?ed andθ{A1,A2,A3}

Y

(A)is the set{S1,S2,127|3456}.Following our practise for the M-rule,for A=

{S1,S2,S3}we simplifyθ{A1,A2,A3}

Y

(A)toθY(A)if the partial splits S i, i=1,2,3are such that there is no ambiguity with regards to the iden-tity of the sets A i,i=1,2,3,in the statement of the Y-rule or they are irrelevant to the discussion.

Note that if A i,i=1,2,3as in the statement of the Y-rule are such

that,in addition,?=A1∩ A2?A3,?=A1∩ A3?A2,?= A3∩ A2? A1, and A1∩A2∩A3=?it is easy to see thatθY applies trivially to A.Also note that for anyΣ∈P(X)and any3partial splits S1,S2,S3∈Σof X,we have

Σ (Σ∪θY({S1,S2,S3})?.

3First closure rule relationships

In this section we?rst restate the Z-(closure)rule which was used in[13]in

the context of a supernetwork construction approach and then investigate

the relationship between the Y-,M-,and Z-rule.

Also originally due to Meacham[18],the Z-ruleθZ can be restated as

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follows:Suppose S1,S2∈Σ(X)are two distinct partial splits of X.

(θZ)If there exists some A i∈S i,i=1,2such that

?∈{A1∩A2,A2∩ A1, A1∩ A2}and A1∩ A2=?(3) then replace A={S1,S2}by the setθY(A)which comprises of the partial splits( A1∪ A2)|A1and A2|(A1∪A2).

Note that any two compatible partial splits of X satisfy the condition in(3).

With this third closure rule at hand we are now in the position to present a?rst easy to verify result.Suppose S1,S2,and S3are3distinct partial splits of X such that there exist parts A i∈S i,i=1,2,3as in the statement of the Y-rule.If,in addition, A1∩ A2∩ A3=?and A1?A2∪A3,then the partial split A1| A1∪( A2∩ A3)generated byθY is also generated by?rst applyingθM to S2and S3(with regards to A2∩ A3=?)and then applying θM to the resulting partial split A2∪A3| A2∩ A3and S1.

In addition,we have the following result whose straight forward proof we leave to the reader.

Proposition3.1Suppose S1is a full split of X.Then the following state-ments hold.

(i)If S2is a partial X-split andθZ applies toΣ={S1,S2},then

θM(Σ)?=θZ(Σ).

(ii)If S2and S3are partial X-splits so thatθY applies toΣ={S1,S2,S3} andθZ applies to{S1,S2}and{S1,S3}.Then

θZ(S1,S i))?.

(θY(Σ)∪ j=2,3θM(S1,S j))?=(

i∈{2,3}

4Closure rules and weakly compatible collections of partial splits

In this section we introduce the notion of a weakly compatible collection of partial splits and study properties of the Y-and M-rules regarding such collections.A particular focus lies on the study of circular collections of partial splits which we also introduce.As we will see,they form a very rich subclass of such collections of partial splits.

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4.1Weakly compatible collections of partial splits

We start this section with a de?nition that generalizes the concept of weak compatibility for(full)splits of X[1]to partial splits of X.Suppose S i= A i| A i∈Σ(X),i=1,2,3,are three partial X-splits.Then we call S1,S2,S3 weakly compatible if at least one of the four intersections

A1∩A2∩A3, A1∩ A2∩A3, A1∩A2∩ A3,A1∩ A2∩ A3(4) is empty1.Since the roles of A i and A i in S i,i=1,2,3,can be interchanged without changing S1,S2,S3we have that S1,S2,S3are weakly compatible if and only if at least one of the four intersections

A1∩ A2∩ A3,A1∩A2∩ A3,A1∩ A2∩A3, A1∩A2∩A3

is empty.More generally,we call a collectionΣ?Σ(X)of partial X-splits weakly compatible if every three partial splits inΣare weakly compatible.To give an example,the partial splits S1=123|4567,S2=124|3567,and S3= 235|146are weakly compatible whereas the partial splits S3,S4=24|135, and S5=21|346are not.Thus,{S1,...,S5}is not weakly compatible.Note that,like in the case of(full)splits,it is easy to see that any collection of pairwise compatible partial splits is also weakly compatible. Clearly any three partial splits S i=A i| A i∈Σ(X),i=1,2,3,for which precisely one of the four intersections in(4)is empty also satis?es Condition (2).ThusθY may be applied to S1,S2,S3.However,as the example of the set{127|3456,1234|567,235|146}shows,application ofθY to a weakly compatible collection of partial splits does not,in general,yield a weakly compatible collection of partial splits.Also it should be noted thatθM applied to a weakly compatible collection of partial splits does not always yield a weakly compatible collection of partial splits.

However,the next result whose proof is straight forward holds.

Lemma4.1SupposeΣ,Σ′?Σ(X).IfΣ′is weakly compatible andΣ Σ′, thenΣmust also be weakly compatible.

4.2Circular collections of partial splits

We now turn our attention to the study of a special class of weakly compati-ble collections of partial splits called circular collections of partial splits.To

be able to state their de?nition,we require some more terminology which

we introduce next.

A cycle C is a connected graph with|V(C)|≥3and every vertex has

degree2.We call C an X-cycle if the vertex set of C is X.For x i∈X (1≤i≤n:=|X|)and C an X-cycle,we call x1,x2,...,x n,x n+1=x1a

vertex ordering(of C)if the edge set of C coincides with the set of all2-sets

{x i,x i+1}of X,i=1,...,n.

For a graph G=(V,E)and some subset E′of E,we denote by G?E′the

graph obtained from G by deleting the edges in E′.We say that a partial X-

split A| A is displayed by an X-cycle C if there exist two distinct edges e1and e2in C such that the vertex set of one of the two components of C?{e1,e2}

contains A and the other one contains A.More generally,we say that a setΣ?Σ(X)of partial splits is displayed by an X-cycle C if every partial split inΣis displayed by C.Finally,we say that a collectionΣ?Σ(X) is circular if there exists some X-cycle C such that every partial split inΣis displayed by C.Note that every split collection inΣ(X)displayed by a circular phylogenetic network is circular.

As is well-known,every circular split system is in particular weakly com-

patible.The next result shows that an analogous result holds for collections

of partial splits.

Lemma4.2SupposeΣ?Σ(X).IfΣis circular thenΣis also weakly compatible.

Proof:Suppose C is an X-cycle that displaysΣbut there exist three partial

splits S1,S2,S3∈Σsuch that with A i∈S i,i=1,2,3,playing the role of their namesakes in(4)none of the four intersections in(4)is empty.Then S1and S2are incompatible and,since S1and S2are displayed by C,there must exist edges e1,e′1,e2,e′2∈E(C)such that,for all i,j∈{1,2}distinct, the vertex set of one component of C?{e i,e′i}contains A i∪e j and the other contains A i∪e′j.Since S3is displayed by C and neither A1∩A2∩A3nor A1∩ A2∩A3,nor A1∩A2∩ A3is empty,it follows that A1∩ A2∩ A3=?, which is impossible.

Lemma4.3SupposeΣ,Σ′?Σ(X).IfΣ′is displayed by an X-cycle C and Σ Σ′,thenΣis also displayed by C.

4.3Circularity and the M-and Y-rule

As was noted earlier,neither the Y-rule nor the M-rule preserve weak com-patibility in general.As the next result shows,the situation is di?erent for the special case of circular collections of partial splits.

Proposition4.4SupposeΣ,Σ′∈P(X)and C is an X-cycle.IfΣ′is obtained fromΣby a single application of eitherθY orθM thenΣis displayed by C if and only ifΣ′is displayed by C.

Proof:SupposeΣ,Σ′∈P(X)and C is an X-cycle.We start the proof with noting that,regardless of whetherΣ′is obtained from a single application of eitherθY orθM toΣ,Σis displayed by C wheneverΣ′is displayed by C in view of Lemma4.3.

Conversely,suppose thatΣis displayed by C.Assume?rst thatΣ′is obtained fromΣby a single application ofθY.Let{S1,S2,S3}?Σbe the set to whichθY is applied.With A i∈S i,i=1,2,3,playing the role of their namesakes in the statement of(2),we may assume without loss of generality that none of the three intersections D1=A1∩A2∩A3,D2= A1∩ A2∩A3, and D3= A1∩A2∩ A3is empty but that A1∩ A2∩ A3=?.It su?ces to show that the partial split S=A3∪(A1∩ A2)| A3is displayed by C. Clearly,if A1∩ A2=?then S=S3and,therefore,S is displayed by C.So assume A1∩ A2=?.Then since by assumption D i=?,i=1,2,3, and S1and S2are displayed by C,there must exist four distinct edges e1,e′1,e2,e′2∈E(C)such that,for all i,j∈{1,2}distinct,one component of C?{e i,e′i}contains A i in its vertex set and e j?A i and the other contains A i in its vertex set and e′j? A i.Without loss of generality,we may assume that X={x1,...,x n},n≥3,that x1,x2,...,x n is a vertex ordering of C, and that e1={x n,x1}.Furthermore,we may also assume without loss of generality that the component of C?{e1,e′1}that contains x1in its vertex set also contains A1.Since D1=?=D2,and S3is displayed by C there must exist distinct paths P and P′in C such that either A3?V(P)or A3?V(P′)(see Figure4).If A3?V(P)then

?= A1∩A2∩ A3=D3

which is impossible.Thus A3?V(P′)must hold.Suppose y,z∈V(C)are such that when starting at x1and traversing C clockwise y is contained in

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A 3and the next vertex y ′on C with y ′∈A 3∪ A 3is contained in A 3whereas

z ∈ A 3and the next vertex z ′on C with z ′∈A 3∪ A 3is contained in A 3

.

1∩A 2∩ A 22

e ′e A 1∩ A 1∩Figure 4:A schematic representation o

f the two alternative locations for A 3(cf proof of Proposition 4.4).The closed curve is the X -cycle C ,the four curves with the short dashes represent the four non-empty intersections A 1∩A 2,A 1∩ A 2, A 1∩ A 2and A 1∩A 2(note that each of them can consist of more than one part),the rectangles mark the intersections D 1and D 2,and the dotted and dashed curves represent the two paths P and P ′on C on which A 3can lie.

Let P ′′denote the path from z ′to y (taken clockwise).Then e 2and

e ′1are edges on P

′′and so A 1∩ A 2?V (P ′′).The choice of y and z ′implies V (P ′′)∩ A 3=?and A 3∪(A 1∩ A 2)?V (P ′′).Hence,the split

V (P ′′)|X ?V (P ′′)which is displayed by C extends the partial split S .Thus C displays S .This concludes the proof in case the applied closure rule applied is θY .

To conclude the proof of the proposition suppose Σ′is obtained from Σby a single application of θM .Let {S 1,S 2}?Σbe the set to which θM is applied.With A i ∈S i ,i =1,2,we may assume without loss of generality

that A 1∩A 2=?and A 1∩ A 2=?.If θM applies trivially to Σthen Σ=Σ

′and so Σ′must be displayed by C .If θM does not apply trivially to Σit su?ces to show that C displays (A 1∩A 2)|( A 1∪ A 2).

Since S 1and S 2are displayed by C there must exist edges e i ,e ′i ∈E (C )

such that the vertex set of one of the two components P i ,P ′i of C ?{e i ,e ′i }

contains A i and the other contains A i ,i =1,2.Put k :=|{e 1,e ′1}∩{e 2,e ′2}|

and note that 0≤k ≤2.Without loss of generality,we may assume

A i ?V (P i )and A i ?V (P ′i ),i =1,2.Then,?=

A 1∩A 2?V (P 1)∩V (P 2).Since V (P 1)∩V (P 2)is the vertex set of one of the 4?k components of C

14

with the edges e i,e′i,i=1,2removed,it follows that there must exist two distinct edges e3,e4among the edges e1,e′1,e2,e′2so that the vertex set of one of the two components of C?{e3,e4}is V(P1)∩V(P2).Since

X?(V(P1)∩V(P2))=(X?V(P1))∪(X?V(P2))=V(P′1)∪V(P′2) is the vertex set of the other component of C?{e3,e4}and A i?V(P′i), i=1,2,it follows that C displays(A1∩A2)|( A1∪ A2).This concludes the proof in caseΣ′is obtained fromΣby a single application ofθM and thus the proof of the proposition.

and call n the length ofσ.In addition,we call the last element ofσa split closure ofΣ.Note that in caseΣn=ω,θapplies only trivially toΣn.

The following combinations of(P)andθare of interest to us:

(a)(P)is the property thatΣis weakly compatible andθis the Y-rule.

(b)(P)is unspeci?ed andθis the M-rule.

(c)(P)is the property thatΣis weakly compatible andθis the M/Y-

combination closure ruleθM/Y which appliesθM orθY toΣ.

To elucidate the notion of a split closure sequence and a split closure associated to a set in P(X)we next present an example for the assignments of(P)andθspeci?ed in(a).Consider the set X={1,2,3,4,5}together with the collectionΣcomprising of the partial X-splits S1=12|34,S2= 23|14,S3=15|24,and S4=45|13.Clearly,Σis displayed by an X-cycle C with vertex ordering1,2,3,4,5.ThusΣis circular and so,by Lemma4.2,Σis weakly compatible.NowθY applied to{S1,S2,S3}generates the split S′3=15|234,θY applied to{S1,S2,S4}generates the split S′4=45|123and θY applied to{S2,S′3,S′4}generates the split S′2=145|23.Since every subset ofΣ′={S1,S′2,S′3,S′4}of size three contains two pairwise compatible full splits,θY can only be applied trivially toΣ′.Hence,the sequence S0=Σ,Σ1={S1,S2,S′3,S4},Σ2={S1,S2,S′3,S′4},Σ′is a split closure sequence forΣof length3andΣ′is a split closure forΣ.

Regarding(c),it should be noted that even if for someΣ∈P(X)two distinct split closure sequences have the same length and terminate in the same elementΣ′=ωone of them might utilise fewer applications ofθY (and thus more applications ofθM!)than the other.For the previous example,one way to construct two such sequences is to exploit the following relationship between the Y-rule and the M-rule for{S2,S′3,S′4}. Proposition5.1SupposeΣ={S i=A i| A i:i=1,2,3}∈P(X)is such that A1?A2and A2? A1? A3? A1∪ A2.If the Y-rule applies toΣthen θY(Σ)?={ A1∪ A2|A1,S2,S3}={S3}∪θM(S1,S2)?.

Proof:Assume thatΣand S i and A i,i=1,2,3,are such that the assump-tions of the proposition are satis?ed.Then A1∩ A2=?.Combined with the assumption thatθY applies toΣ,it follows that either(2)is satis?ed with

A i,i=1,2,3playing the roles of their namesakes in the statement of(2)or

(2)is satis?ed with A3playing the role of A3and A i playing the role of A i,

16

i=1,2,in that statement.But the latter alternative cannot hold since this implies A1∩A2∩ A3=?whereas the assumption A3? A1∪ A2implies A1∩A2∩ A3?A1∩A2∩( A1∪ A2)=(A1∩A2∩ A1)∪(A1∩A2∩ A2)=?. Hence,(2)is satis?ed with A i,i=1,2,3playing the roles of their namesakes in the statement of(2).Let S′i,i=1,2,3be as in the statement of the Y-rule.Then A2? A1? A3implies S′1= A1∪ A2|A1.And since A1?A2,we have S′2=S2and A1∩ A2=?which in turn implies S′3=S3.Consequently,

θY(Σ)?={ A1∪ A2|A1,S2,S3}.

To observe the remaining set equality,note that since(2)is satis?ed with A i,i=1,2,3playing the roles of their namesakes in the statement of(2) neither A1∩A2nor A1∩ A2can be empty.Let S′1be as in the statement of the M-rule.Then A1?A2implies S′1= A1∪ A2|A1and S′2= A1∩ A2|A2. This implies the sought after set equality and thus proves the proposition.

Σ=ωis a split closure ofΣandΣr and Σr+1are two consecutive elements in a split closure sequence forΣ.

(i)IfΣr is weakly compatible,Σr

Σ. (ii)IfΣr+1is obtained fromΣr by one application ofθM andΣr

Σ.

Proof:SupposeΣ,

(i)AssumeΣr+1is obtained fromΣr by applyingθY to some set{S1,S2,S3} contained inΣr.For i=1,2,3and with A i∈S i playing the role of their namesakes in the statement of(2),we obtain

S′3=A3∪(A1∩ A2)| A3,S′2=A′2∪(A1∩ A3)| A2,and S′1= A1∪( A3∩ A2)|A1. It follows that

Σr+1=(Σr∪{S′1,S′2,S′3})?.

SinceΣr Σwith S′′i extending S i,i=1,2,3.Without loss of generality we may assume for all i that A

i?A′′i and A i? A′′i.SinceΣ=ωand so θY applies trivially to

Σ.SinceΣis weakly compatible, Lemma4.1implies thatΣr+1is weakly compatible.

(ii):SupposeΣr+1is obtained fromΣr by applyingθM to some set {S1,S2}?Σr.Put S i=A i| A i,i=1,2,and assume without loss of generality,that A1∩A2=?and A1∩ A2=?.Then

S′1=A1∩A2| A1∪ A′′2and S′2=A1∪A2| A1∩ A′′2

and so

Σr+1=(Σr∪{S′1,S′2})?.

By assumption,Σr

Σwith S′′i extending S i,i=1,2.Without loss of generality we may assume A i?A′′i and A i? A′′i,i=1,2.Then A′′1∩A′′2=?and A′′1∩ A′′2=?. Since,by assumption,Σwe have θM(S′′1,S′′2) Σ,j=3,4, so that A′′1∩A′′2| A′′1∪ A′′2is extended by S3and A′′1∩ A′′2|A′′1∪A′′2is extended by S4.Without loss of generality,we may assume that A′′1∩A′′2?A3and A′′1∪ A′′2? A3and that A′′1∪A′′2?A4and A′′1∩ A′′2? A4.Then

A1∩A2?A′′1∩A′′2?A3and A1∪ A2? A′′1∪ A′′2? A′′3

and so S3extends S′1.Similarly,it follows that S4extends S′2.Thus,Σr+1

With this result in hand,we are now in the position to present a key result.

18

Theorem5.3SupposeΣ∈P(X).Then any two split closures forΣare the same if

(i)Σis weakly compatible and solely the Y-rule is used to obtain a split

closure forΣ,

(ii)solely the M-rule is used to obtain a split closure forΣ,or

(iii)Σis weakly compatible and solely the M/Y-rule is used to obtain a split closure forΣ.

Proof:SupposeΣ∈P(X).We start with remarking that we prove State-ments(i),(ii)and(iii)collectively as the proof of all three statements relies on an inductive argument on the length of a split closure sequence forΣ. However,since the arguments for the inductive step di?er under the assump-tions made in(i),(ii)and(iii),we discuss each inductive step separately.

Suppose that the assumptions made in(i)or in(ii)or in(iii)hold.If every split closure ofΣisωthen the theorem holds trivially.So we may assume that there exists a split closureΣ=ω.We proceed by showing that every other split closure ofΣmust equal

Σ;(5) in(ii)then,for all i∈{0,1,...,n},

Σi

Σ.(7) We start with assuming thatΣsatis?es the assumptions made in(i), that is,Σis weakly compatible and solely the Y-rule is used to generate the elements ofσ.If i=0then(5)obviously holds since thenΣi=Σ0andΣ0 satis?es the properties stated in(5).Now suppose that(5)holds for some i∈{0,1,...,n?1}.Then,by Lemma5.2(i),Σi+1is weakly compatible and Σi+1

Next,assume that only the M-rule is used to generate the elements in Σ.If i=0,then(6)holds since thenΣi=Σ0andΣ0satis?es(6).Assume that(6)holds for some i∈{0,1,...,n?1}.Then Lemma5.2(ii)implies Σ

r+1

Σ,and one of the following two cases must hold.Either(a)Σr+1is obtained fromΣr by applyingθY or(b)Σr+1 is obtained fromΣr by applyingθM.

If Case(a)holds,the proof of the inductive step in(i)implies thatΣi+1 is weakly compatible andΣi+1

Σfollows from the proof of the inductive step in(ii).ThatΣi+1is weakly compatible follows from Lemma5.2(ii)and the fact that

Σregardless of whether we are assuming(i)or(ii)or(iii)to hold.In case of(i)holding and applying(5)to i=n or(iii)holding and applying(7)to i=n,we see thatΣn is weakly compatible.By interchanging the roles ofΣn and Σ Σn.Thus,under the assumptions made in(i)or(ii)or(iii),we have

Extending in the case of(P)denoting the condition“Σis weakly com-patible”andθdenoting either the Y-rule or the M/Y-rule,the de?nition of the split closure to non weakly compatible sets in P(X)by de?ning the split closure of such sets to beω,we obtain

Corollary5.4Supposeθis either the Y-or M-or M/Y-rule.Then for anyΣ∈P(X),any two split closures forΣobtained viaθare the same.

Bearing in mind Corollary5.4,we denote forθ∈{θY,θM,θM/Y}the

split closure of a setΣ∈P(X)by Σ θ,Note that| Σ θ

Y |≤|Σ|but that

neither| Σ θ

M |≤|Σ|nor| Σ θ

M/Y

|≤|Σ|have to hold.Also note that,if we

denote the collection P(X)∪{ω}by Pω(X),de?ne ω θ=ωfor some closure ruleθ,and putΣ ωfor allΣ∈P(X),then the split closure with respect toθ∈{θY,θM,M/Y}satis?es the usual properties of a closure operation. More precisely,for allΣ,Σ′∈Pω(X)we haveΣ Σ θ,ifΣ Σ′then Σ θ Σ′ θ,and Σ θ θ= Σ θ.

20

excel表单控件与ActiveX控件概念

工作表中的表单、表单控件和ActiveX 控件概念 是的,确实如此。在Microsoft Excel 中,使用少量或者无需 使用Microsoft Visual Basic for Applications (VBA) 代码即可 创建出色的表单。使用表单以及可以向其中添加的许多控件和 对象,您可以显著地增强工作表中的数据项并改善工作表的显 示方式。 ? ? 什么是表单? 无论是打印表单还是联机表单都是一种具有标准结构和格式的文档,这种文档可让用户更轻松地捕获、组织和编辑信息。 ?打印表单含有说明、格式、标签以及用于写入或键入数据的空格。您可以使用Excel 和Excel 模板创建打印表单。 ?联机表单包含与打印表单相同的功能。此外,联机表单还包含控件。控件是用于显示数据或者更便于用户输入或编辑数据、执行操作或进行选择的对象。通常,控件可使表单更便于使用。例如,列表框、选项按钮和命令按钮都是常用控件。通过运行(VBA) 代码,控件还可以运行指定的和响应事件,如鼠标点击。 您可以使用Excel 通过多种方式创建打印表单和联机表单。 Excel 表单的类型 您可以在Excel 中创建多种类型的表单:数据表单、含有表单和ActiveX 控件的工作表以及VBA 用户表单。可以单独使用每种类型的表单,也可以通过不同方式将它们结合在一起来创建适合您的解决方案。 数据表单

为在无需水平滚动的情况下在单元格区域或表格中输入或显示一整行信息提供了一种便捷方式。您可能会发现,当数据的列数超过可以在屏幕上查看的数据列数时,使用数据表单可以使数据输入变得更容易,而无需在列之间进行移动。如果以标签的形式将列标题列出的文本框这一简单表单足以满足您的需求,而且您不需要使用复杂的或自定义的表单功能(例如列表框或调节钮),则可以使用数据表单。 Excel 可以为您的或自动生成内 置数据表单。数据表单会在一个对 话框中将所有列标题都显示为标 签。每个标签旁边都有一个空白文 本框,您可以在其中输入每一列的 数据,最多可以输入32 列数据。 在数据表单中,您可以输入新行, 通过导航查找行,或者(基于单元 格内容)更新行及删除行。如果某 个单元格包含,则公式结果会显示 在数据表单中,但您不能使用数据 表单更改该公式。 含有表单和ActiveX 控件的工作表 工作表是一种类型的表单,可让您在网格中输入数据和查看数据,Excel 工作表中已经内置了多种类似控件的功能,如注释和数据验证。单元格类似于文本框,因为您可以在单元格中输入内容以及通过多种方式设置单元格的格式。单元格通常用作标签,通过调整单元格高度和宽度以及合并单元格,您可以将工作表用作简单的数据输入表单。其他类似控件的功能(如单元格注释、超链接、背景图像、数据验证、条件格式、嵌入图表和自动筛选)可使工作表充当高级表单。 为增加灵活性,您可以向工作表的“”添加控件和其他绘图对象,并将它们与工作表单元格相结合和配合。例如,您可以使用列表框控件方便用户从项目列表中选择项目。还可以使用调节钮控件方便用户输入数字。 因为控件和对象存储在绘图画布中,所以您可以显示或查看不受行和列边界限制的关联文本旁边的控件和对象,而无需更改工作表中数据网格或表的布局。在大多数情况下,还可以将其中许多控件链接到工作表中的单元格,而无需使用VBA 代码即可使它们正常工作。您可以设置相关属性来确定控件是自由浮动还是与单元格一起移动和改变大小。例如,在对区域进行排序时,您可能有一个希望与基础单元格一起移动的复选框。不过,如果您有一个希望一直保持在特定位置的列表框,则您可能希望它不与其基础单元格一起移动。 Excel 有两种类型的控件:表单控件和ActiveX 控件。除这两个控件集之外,您还可以通过绘图工具(如、、SmartArt 图形或文本框)添加对象。 以下部分介绍这些控件和绘图对象,此外,还更为详细地介绍如何使用这些控件和对象。

.NET4.0 用户控件的概述

https://www.doczj.com/doc/b812298092.html,4.0 用户控件的概述 用户控件是页面的一段,包含了静态HTML代码和服务器控件。其优点在于一旦创建了一个用户控件,可以在同一个应用的多个页面中重用。并且,用户可以在Web用户控件中,添加该控件的属性、事件和方法。 1.什么是用户控件 用户控件(后缀名为.ascx)文件与https://www.doczj.com/doc/b812298092.html,网页窗体(后缀名为.aspx)文件相似。就像网页窗体一样,用户控件由用户接口部分和控制标记组成,而且可以使用嵌入脚本或者.cs代码后置文件。用户控件能够包含网页所能包含的任何东西,包括静态HTML内容和https://www.doczj.com/doc/b812298092.html,控件,它们也作为页面对象(Page Object)接收同样的事件(如Load和PreRender),也能够通过属性(如Application,Session,Request 和Response)来展示https://www.doczj.com/doc/b812298092.html,内建对象。 用户控件使程序员能够很容易地跨Web应用程序划分和重复使用公共UI功能。与窗体页相同,用户可以使用任何文本编辑器创作用户控件,或者使用代码隐藏类开发用户控件。 此外,用户控件可以在第一次请求时被编译并存储在服务器内存中,从而缩短以后请求的响应时间。与服务器端包含文件(SSI)相比,用户控件通过访问由https://www.doczj.com/doc/b812298092.html,提供的对象模型支持,使程序员具有更大的灵活性。程序员可以对在控件中声明的任何属性进行编程,而不只是包含其他文件提供的功能,这与其他任何https://www.doczj.com/doc/b812298092.html,服务器控件一样。 此外,可以独立于包含用户控件的窗体页中除该控件以外的部分来缓存该控件的输出。这一技术称作片段缓存,适当地使用该技术能够提高站点的性能。例如,如果用户控件包含提出数据库请求的https://www.doczj.com/doc/b812298092.html,服务器控件,但该页的其余部分只包含文本和在服务器上运行的简单代码,则程序员可以对用户控件执行片段缓存,以改进应用程序的性能。 用户控件与普通网页页面的区别是: ●用户控件开始于控件指令而不是页面指令。 ●用户控件的文件后缀是.ascx,而不是.aspx。它的后置代码文件继承于 https://www.doczj.com/doc/b812298092.html,erControl类.事实上,UserControl类和Page类都继承于同一个 TemplateControl类,所有它们能够共享很多相同的方法和事件。 ●没有@Page指令,而是包含@Control指令,该指令对配置及其他属性进行定义。 ●用户控件不能被客户端直接访问,不能作为独立文件运行,而必须像处理任何控件一 样,将它们添加到https://www.doczj.com/doc/b812298092.html,页中。 ●用户控件没有html、body、form元素,但同样可以在用户控件上使用HTML元素和 Web控件。 用户可以将常用的内容或者控件以及控件的运行程序逻辑,设计为用户控件,

学生信息管理系统java课程设计(含源代码)

JAVA程序设计课程设计报告 课题: 学生信息管理系统 姓名: 学号: 同组姓名: 专业班级: 指导教师: 设计时间: 评阅意见: 评定成绩:

目录 一、系统描述 (2) 1、需要实现的功能 (3) 2、设计目的 (3) 二、分析与设计 (3) 1、功能模块划分 (3) 2、数据库结构描述 (4) 3、系统详细设计文档 (6) 4、各个模块的实现方法描述 (9) 5、测试数据及期望结果 (11) 三、系统测试 (16) 四、心得体会 (23) 五、参考文献 (24) 六、附录 (24)

一、系统描述 1、需求实现的功能 、录入学生基本信息的功能 学生基本信息主要包括:学号、姓名、年龄、出生地、专业、班级总学分,在插入时,如果数据库已经存在该学号,则不能再插入该学号。 、修改学生基本信息的功能 在管理员模式下,只要在表格中选中某个学生,就可以对该学生信息进行修改。 、查询学生基本信息的功能 可使用“姓名”对已存有的学生资料进行查询。 、删除学生基本信息的功能 在管理员模式下,只要选择表格中的某个学生,就可以删除该学生。 、用户登陆 用不同的登录权限可以进入不同的后台界面,从而实现权限操作。 、用户登陆信息设置 可以修改用户登陆密码 2、设计目的 学生信息管理系统是一个教育单位不可缺少的部分。一个功能齐全、简单易用的信息管理系统不但能有效地减轻学校相关工作人员的工作负担,它的内容对于学校的决策者和管理者来说都至关重要。所以学生信息管理系统应该能够为用户提供充足的信息和快捷的查询手段。但一直以来人们使用传统人工的方式管理文件档案、统计和查询数据,这种管理方式存在着许多缺点,如:效率低、保密性差、人工的大量浪费;另外时间一长,将产生大量的文件和数据,这对于查找、更新和维护都带来了不少困难。随着科学技术的不断提高,计算机科学日渐成熟,

第六章 对话框控件

学习目标: ?掌握CommonDialog。 ?掌握文件操作相关的对话框。 ?理解打印对话框。 6.1对话框: 对话框是一种用户界面接口,用于同用户进行交互,完成一些特定的任务,简单的对话框有对用户操作进行提示的对话框,对重要操作要求用户进行决定的交互对话框等。 这类任务能被独立出来,作为通用的交互处理过程。这些能被独立出来作为通用交互过程的任务常见如下一些: (1)文件选取。 (2)保存设置。 (3)路径选取。 (4)字体选取。 (5)颜色选取。 (6)打印设置。 (7)打印预览框。 在.NET中这些组件是在https://www.doczj.com/doc/b812298092.html,monDialog的基础上发展而来。

6.1.1Common pialog: CommonDialog是.NET中对话框组件的基础,它是System.Windows.Forms命名空间下的一个抽象类,在程序中不能直接使用。 CommonDialog公开了2个方法和一个属性,即:ShowDialog()/ShowDialog(IWin32Window)方法和Reset()方法以及Tag属性。 ShowDialog是用于显示对话框。ShowDialog()有一个重载形式:ShowDialog(IWin32Window),IWin32Window在这里指一个窗口句柄,在调用中,这个参数应该被赋值成要显示的对话框的父窗体。 注意:句柄是Window中的一个常用词语,可以把它理解为一个标识符号,只是这个标识符号是一个数字。相应的窗口句柄就是窗口的标标识符。 Reset方法: 使用过程中可能改变初始值,当需要让所有的初值回到原来的状态时,调用Reset能达到目的。 Tag属性: Tag没有具体含义,它可以让用户在对话框控件中存储、维护自己的数据。这个数据由用户自己的代码解释。 对话框的返回值(ShowDialog的返回值): 对话框通过调用ShowDialog()调用后,返回一个类型为DialogResult 值,其中DialogResult.OK指出用户成功完成了操作,成功选取了文

vf表单控件的使用说明

一、标签 标签能够显示多个字符构成的文本,用于设计表单上所需的文字性提示信息。标签和大多数控件的不同点在于运行表单时不能用《tab》键来选择标签。 常用的标签属性及其作用如下。 1、Caption:确定标签处显示的文本。 2、Visible:设置标签可见还是隐藏。 3、AutoSize:确定是否根据标签上显示文本的长度,自动调整标签大小。 4、BackStyle:确定标签是否透明。 5、WordWrap:确定标签上显示的文本能否换行。 6、FontSize:确定标签上显示文本所采用的字号。 7、FontName:确定标签上显示文本所采用的字体。 8、ForeColor:确定标签上显示的文本颜色。 二、命令按钮和命令按钮组 在各种窗口或对话框中几乎都要使用一个或多个命令按钮。一旦用户单击一个命令按钮,就可实现某种规定的操作。例如,各种对话框中的“确定”按钮,当用户单击时将结束对话框的操作。 VisualForPro中的命令按钮控件同样用于完成特定的操作。操作的代码通常放在命令按钮的“单击”事件(即Click Event)代码中。这样,运行表单时,当用户单击命令按钮时便会执行Click事件代码。如果在表单运行中,某个命令按钮获得了焦点(这时,这个命令按钮上会比其他命令按钮多一个线框),则当用户按下《Enter》键或空格键时,也会执行这个命令按钮的Click时间代码。 常用的命令按钮属性及其作用如下: 1、Caption:设置在按钮上显示的文本。 2、Default:在表单运行中,当命令按钮以外的某些控件(如文本框)获得焦点时,若 用户按下《Enter》键,将执行Default属性值为.T.的那个命令按钮的click事件代码。 3、Cancel:如果设置该属性值为.T.,则当用户按下键时,将执行命令按钮的click 事件的代码。 4、Enabled:指明按钮是否失效,即是否被选择。当Enabled属性值为.f.时,用户无法 选择该按钮。 5、DisabledPicture:指定按钮失效时在按钮上显示的.bmp文件。 6、DownPicture:指定在按钮按下时按钮上显示的.bmp文件。 7、Visible:指明按钮是否可见。 8、Picture:指明显示在按钮上的.bmp文件。 命令按钮组时一组命令按钮,是容器对象。使用命令按钮组便于对一组命令按钮进行统一操作和设置。命令按钮组的ButtonCount属性值,决定组中命令按钮的个数。 表单运行时,当用户单击组中某个命令按钮时,命令按钮组的Value属性可以返回所单击按钮的序号。若要单独设置组中的某个命令按钮的属性,可以使用命令按钮组的快捷菜单中的“编辑”命令选择某个按钮,在“属性”窗口中设置其属性。若为组中某个按钮的Click事件写了代码,当单击这个按钮时,将执行该按钮的Click事件代码而不是组的Click事件代码。 三、选项按钮组 选项按钮组是常用的一种控件,用在各种对话框中,让用户从给定几个操作中选择一个。例如“文件”菜单中“新建”菜单项打开“新建”对话框,该对话框中有一个标题为“文件类型”的选项按钮组,让用户选择建立哪一种类型的文件。

学生学籍管理系统(含java源代码)

学生学籍管理详细设计 学号:____________ 姓名:____________ 班级:____________ 一、设计题目: 学生学籍管理 二:设计内容: 设计GUI学生学籍管理界面,用户可以加入学生信息,并对基本信息进行修改,添加,查询,删除。 三:设计要求: 进行简单的学生信息管理。 四:总体设计 (1)登陆界面的设计 (2)主窗体的设计 (3)添加学生信息窗体 (4)查询学生信息窗体 (5)修改学生信息窗体 (6)删除学生信息窗体 (7)事件响应的处理 五:具体设计 (1)程序结构的说明: A.入口程序:; B.登陆界面程序:; C.主窗体程序:; D.添加信息窗口程序:; E.修改信息窗口程序:;

F.查询信息窗口程序:; G.删除信息窗口程序:; H.程序数据连接:; (2)程序代码及分析说明 A.程序源代码(已提交) 是程序的入口。使登录窗口位于窗口中间,并且不可改变窗口大小。 是程序的登陆窗体。输入用户名和密码(用户名和密码在数据库的password表中)点击“进入系统”,然后登陆界面消失;出现要操作的界面(屏幕左上角)。是添加信息界面。添加基本信息后,点击“添加信息”按钮,将信息加入xinxi 表中。 是修改信息界面。输入要修改的学号或姓名(两者数其一或全部输入),并输入所有信息,点击“修改信息”按钮(如果数据库中不存在此学号,则弹出对话框“无此学生信息”),若有则修改。 是删除信息界面。输入要删除的学生的学号,点击“删除信息”按钮,弹出确认删除对话框,即可删除该生信息。 是查询信息界面。输入要查询的学生学号,点击“信息查询”按钮,在相应的文本区里显示查询的信息。 H:源代码 ; import .*; etScreenSize(); Dimension frameSize=(); if> { =; } if> { =; } ( (true); } public static void main(String[] args) { try{ ()); } catch(Exception e) { (); } new student(); } }

MFC对话框程序中的各组件常用方法

MFC对话框程序中的各组件常用方法: Static Text: 将ID号改成唯一的一个,如:IDC_XX,然后进一次类向导点确定产生这个ID,之后更改Caption属性: GetDlgItem(IDC_XX)->SetWindowText(L"dsgdhfgdffd"); 设置字体: CFont *pFont = new CFont; pFont->CreatePointFont(120,_T("华文行楷")); GetDlgItem(IDC_XX)->SetFont(pFont); Edit Control: 设置文本: SetDlgItemText(IDC_XX,L"iuewurebfdjf"); 获取所有输入: 建立类向导创建一个成员变量(假设是shuru1,shuru2……)类型选value,变量类型任选。 UpdateData(true); GetDlgItem(IDC_XX)->SetWindowText(shuru1); 第一句更新所有建立了变量的对话框组件,获取输入的值。第二句将前面的IDC_XX的静态文本内容改为shuru1输入的内容。 若类型选用control: 1.设置只读属性: shuru1.SetReadOnly(true); 2.判断edit中光标状态并得到选中内容(richedit同样适用) int nStart, nEnd; CString strTemp; shuru1.GetSel(nStart, nEnd); if(nStart == nEnd) { strTemp.Format(_T(" 光标在%d" ), nStart); AfxMessageBox(strTemp); } else { //得到edit选中的内容 shuru1.GetWindowText(strTemp); strTemp = strTemp.Mid(nStart,nEnd-nStart); AfxMessageBox(strTemp); } 其中nStart和nEnd分别表示光标的起始和终止位置,从0开始。strTemp.Format 方法用于格式化字符串。AfxMessageBox(strTemp)显示一个提示对话框,其内容是字符串strTemp。 strTemp = strTemp.Mid(nStart,nEnd-nStart)返回一个被截取的字符串,从nStart开始,长度为nEnd-nStart。如果nStart == nEnd说明没有选择文本。 注:SetSel(0,-1)表示全选;SetSel(-1,i)表示删除所选。

常用服务器端控件

常用服务器端控件 Windows控件与Web服务器控件的主要区别: Windows控件的属性、方法、事件都是在本机上执行的; Web服务器控件的属性、方法、事件则全部是在服务器端执行的。 Web应用程序的执行方式: 在Web应用程序中,用户通过客户端浏览器操作Web页面时,对Web服务器控件的每个请求都要发送到服务器端,服务器进行处理后,再将处理结果转换为客户端脚本发送到客户端显示。 https://www.doczj.com/doc/b812298092.html,控件的基本概念 1控件分类 (1)标准控件 (2)数据控件 (3)验证控件 (4)站点导航控件 (5)WebPart控件 (6)登陆控件 基本控件 1 标签控件 2 按钮控件 3 TextBox控件 4 CheckBox控件与CheckBoxList控件 5 RadioButton控件与RadioButtonList控件 6 ListBox控件和DropDownList控件 7 Table控件 8 HiddenField控件 5.1.1 按钮控件 VS2005中有以下三种类型的按钮控件: 1.Button控件:与Windows窗体的Button控件用法相同。 2.LinkButton控件:外观与Hyperlink控件相同,但在功能上与Button控件完全相同。 3.ImageButton控件:以图片形式显示的按钮。 三种类型的按钮在鼠标单击时都可以将窗体提交给服务器,并触发服务器端对应的Click事件,然后在服务器端执行相应的事件代码。 5.1.2 TextBox控件 1. 常用的基本属性 1) AutoPostBack属性:决定控件中文本修改后,是否自动回发到服务器。该属性默认值为false, 即修改文本后并不立即回发到服务器,而是等窗体被提交后一并处理。 2) TextMode属性:用于设置文本框接受文本的行为模式。共有三种属性值:MultiLine(多行输 入模式);Password(密码输入模式);SingleLine(单行输入模式)。默认情况下,该属性为 SingleLine。 2. 常用的事件 TextChanged事件:文本框的内容发生更改导致窗体回发服务器时触发。注意,是否触发该事件与AutoPostBack属性相关。

教学设计表单控件--选项按钮组

优秀课堂教学设计 课题:教表单控件选项按钮组 师:教材分马冬艳析:本节课是选自中等职业学校计算机技术专业的《数据库应用技术 VISUAL FOXPRO6.0 》中第六章表单设计中的第三节的内容。节课是在同学们 已经掌握了几种基本表单控件的基础上,进一步学习选项按扭组控件。重点:选项 按钮组的基本属性和特有属性难点:选项按钮组的应用能力目 1)标:通过了解选项按钮组的特性,并予以适当的启发,让学生能够利用此 2)控件具有创造性的设计出实用表单,培养学生的创造力。 3)知识目标:熟知选项按钮组的特性并熟练应用。情感目标:通过讨论增进同学们的感情交流和知识交流。由于书上对本节的内容实例较少且实例多是在以往例 题的基础上添加上此控因此控件属性突出不明显,为此我特地 专对此控件的属性设计了一道例题,不但能突出这个控件的特有属性,而(4) 且能极大的提高学生的学习兴趣,有利有的突出了重点问题,为解决难点课程重组:(5) 做好了铺垫。在精心设置例题的基础上增加了让学生自己根据控件属性设置问题的环节,不但能增加学生学习的兴趣而且有利于学习对本节课的内容进行深层次的思考,从而达到突破难点的目的。学生在学习本节课之前已经学习了一些控件,对于控件的学习已经有了一定学习经验,知道在学习控件的学习过程中应该注意哪些地方。但是由于控件学习的比较多,而且有很多相似的地方学生容易产生厌烦情绪,为了解决这个问题,要在引入此控件时设置好问题情境,引发学生学习兴趣,且鼓励学生进行大胆的学情分析:设想,培养同学们的创造思维能力。根据学生学习能力水平的不同在请同学们上前操作时,按照要操作的内容有选择性的挑选学生上来操作,在做简单操作时挑选那些平时操作不是很熟练且胆子比较小的同学,在培养他们胆量的同时通过完成一些简单操作激发他们的信心。对于那些较有难度且需要进行一不思考的问题,找一些底子比较好但是又不会很快把这个问题解决出来的同学来做,在他做的过程

ASP NET基础知识

https://www.doczj.com/doc/b812298092.html,的两种编码方式是什么,什么是代码内嵌,什么是代码后置?Web页面的父类是谁? 代码内嵌和代码后置。代码内嵌把业务逻辑编码和显示逻辑编码交叉使用。代码后置式业务逻辑代码和显示逻辑代码分开使用。system.web.ui.page 2.Web控件的AutoPostBack属性的作用是什么? 控件的值改变后是否和服务器进行交互(自动回传) 3.验证服务器控件有哪些,他们有哪些常用的属性,ControlToValidate属性的作用是什么?有哪两种服务器控件? RequiredFieldValidator:controltovalidate(验证的控件ID,共有的属性),text,ErrorMessage||||(dropdownlist控件验证时InitialValue属性是如果用户没有改变初始值,会验证失败)CompareValidator:controltocompare(要进行对比的控件),type(比较类型设置),operator(比较运算符,默认为等于),ValueToCompare(进行比较的值) RangeValidator:type(验证类型(5种)),MaximumValue(最大值),MinimumValue(最小值)(包括上下限) RegularExpressionValidator:ValidationExpression(设置要匹配的正则表达式)ValidationSummary:showMessageBox(是否显示弹出的提示消息),ShowSummary(是否显示报告内容) HTML服务器控件和web服务器控件 4.什么是Session,如何进行Session的读写操作,使用什么方法可以及时释放Session?Session 是用于保持状态的对象。Session 允许通过将对象存储在Web服务器的内存中在整个用户会话过程中保持任何对象。 通过键值对的方式进行读写;clear()和abandon()方法 5.运行https://www.doczj.com/doc/b812298092.html,程序需要安装和配置什么,.NET Framework是不是必须要安装? 安装IIS和.NET Framework 必须安装 https://www.doczj.com/doc/b812298092.html,配置信息分别可以存储在什么文件中? web.config文件和machine.config文件中 7.常用服务器控件,如Label、Button、TextBox、HyperLink、DropdownList的常用属性有哪些?label:text ,forecolor,visible Button:CommandName,CauseValidation, TextBox:AutopostBack,TextMode Hyperlink:NavigateUrl(单击Hyperlink时跳转的Url),Text,Target(设置NavigateUrl属性的目标框架),ImageUrl(设置Hyperlink中显示图片文件的Url) Dropdownlist:AutoPostBack 8.XMLHttpRequest对象的常用属性和方法有哪些? 方法是open()和send() 属性:ReadyState和Status,ResponseText,ResponseXML,ResponseStream https://www.doczj.com/doc/b812298092.html,中的常用的指令有哪些?谈谈这些指令的常用属性的作用?

客服端控件与服务器控件的区别

什么时候用html控件,什么时候用"标准控件"? 能不用服务器端控件尽量不用 能用html控件就不要用web控件 服务器端控件效率低 前两句同意,至于后一句, 效率上,纯 html 肯定比 runat=server 低, 对于 runat=server ,事实上 https://www.doczj.com/doc/b812298092.html, 内部帮我们作了许许多多的工作,比如 在 asp/php/jsp 中需要 来维护两次post之间的状态而 帮我们做了这项工作,其内部也是使用Request.Form 类获取值,然后经过一系列的处理周期(https://www.doczj.com/doc/b812298092.html,基于事件驱动) 在一个页面上,前者,只是一个字符流的输出,后者涉及对象的创建,控件层次的维护,大量相关页、控件事件同步,ViewState维护 比如必然导致额外的性能损耗,

但,它带来的是,【开发效率成倍的提升,完整的组件编程模式....】 你不必再一堆的 Request.Form 中绕,你可以引用服务器控件对应,统一的编程模型 如 1. string txt = Requst.Form["MyTextBoxClientName"]; VS string txt2 = MyTextBoxServerID.Text; 2. // js document.form1.action = "?action=delete" // aspx.cs if(Requst.QueryString["action"] == "Delete") { // 执行删除操作 ... } VS // aspx

表单控件常用属性、事件及方法英中对照

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?如下图所示就是一个设置好的多行输入框在表单中显示的样式。 ?第三,下拉菜单。 这个很好理解,下拉菜单包含所有可能的选项。然后填写表单的用户可以通过下拉菜单选择需要的选项。

?第四,单选框。 单选框的含义我们都知道,就是设置多于一个的选项,而用户填写表单的时候只能从中选择一个选项。 ?比如下图所示的一个同意或不同意,只能选择其中一个选项。

?第五,多选框。 多选框的功能其实是只在表单中画一个可以打勾的小框,多选框有多少选项,就设置多少个多选框,然后在每个多选框后面自定义选项内容。 ?如下图所示就是一个多选框的样式,其中,火车、汽车、飞机和轮船这四个选项是在表单中定义的。 ?第六,列表控件。 这个列表控件其实是不经常用到的。起作用是相同格式记录的动态输入,可以根据实际需要灵活新增行数录入相应数据。 使用这个控件,是可以设置好列表头。列表控件支持多种输入类型,包括单行输入框、多行输入框、下来菜单、单选框、复选框和日期,满足多方面的需求; 而且支持自动计算和合计,使用通用运算符+、-、*、/、%等,可以实现列表项目的自动计算输入。其中列表计算项目是不可人工输入的。 如果用户在设计表单的时候确实用到了这个控件,可以设置上一两行试一下,看完表单效果后就知道该如何设置。

aspnet常用控件介绍

Label控件 功能说明:用于显示文本,提示信息,如窗体标题,文本框的标题 命名前缀:Lbl ASPX代码: 重要属性:Text 显示的文本 HyperLink控件 功能说明:建立文本超链接或图片超链接 命名前缀:Hlk ASPX代码:Sample 重要属性:NavigateUrl 链接URL ImageUrl 显示的图片URL Target 目标框架的名称,如"_blank","_top"等 Image控件 功能说明:用于显示图片 命名前缀:Img ASPX代码: 重要属性:ImageUrl 显示的图片URL Button控件 功能说明:用于创建按钮,执行命令 命名前缀:Btn ASPX代码: 重要属性:Text 显示在按钮上的文本 TextBox控件 功能说明:用于显示文本和接收用户输入的文本 命名前缀:Txt ASPX代码: 重要属性:Text 显示在按钮上的文本 TextMode 设置文本的模式,"Single"为单行文本框,"Multiline"为多行文本框 Rows 当TextMode设置为"Multiline"时,文本框显示的行数 Columns 设置文本框的宽度 MaxLength 设置文本框允许输入的最多字符数 CheckBox控件 功能说明:用于创建复选框 命名前缀:Chk

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