C ch Delegate & Event

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N i dungN i dung Delegate

Khi ni m delegate Th c thi delegate Multicast delegate Gi i php cho hm Sort t ng qut

Event Khi ni m event Event & delegate C ch publishing & subscribing Minh h a c ch event

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DelegateDelegate

L p ng gi cc ph ng th c (method signature) Dng trong event-handling model c a C# c tnh

Type safe Object oriented mechanism

Delegate l class: C instance C th ch a nh ng tham chi u n 1 hay nhi u method

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DelegateDelegate

M t delegate nh ngha m t signature Return type Sequence of parameter types

T t c cc method c cng signature c th c add vo th hi n c a delegate

Delegate instance c m t danh sch cc tham chi u method Cho php add (+) cc method C th remove (-) cc method

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Define delegateDefine delegate

public delegate void MyDelegate1(int x, int y)

Delegate cho d ng hm: void Method( int, int )

public delegate string MyDelegate2(float f)

Delegate cho d ng hm: string Method( float )

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Instance delegateInstance delegate

public void Method1(int x, int y){

}MyDelegate1 del1 = new MyDelegate1(Method1);

public string Method2(float f){

}MyDelegate2 del2 = new MyDelegate2(Method2);

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Call DelegateCall Delegate

int x = 5, y = 10;int x = 5, y = 10;del1(x, y);del1(x, y); del1(10, 20);del1(10, 20);

int y = 2;int y = 2;del1(100, y);del1(100, y);

G i del1G i del1

float f =0.5f;float f =0.5f;string s;string s;s = del2(f);s = del2(f);

string s = del2(100f);string s = del2(100f);

G i del2G i del2

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Multi CastMulti Cast

void Print(int x,int y) {void Print(int x,int y) {Console.WriteLine(x = {0}, y = {1}, x, y);Console.WriteLine(x = {0}, y = {1}, x, y);

}}void Sum(int x, int y) {void Sum(int x, int y) {

Console.WriteLine(Tong = {0}, x+y);Console.WriteLine(Tong = {0}, x+y);}}

MyDelegate1 mulDel = new MyDelegate1(Print);MyDelegate1 mulDel = new MyDelegate1(Print);mulDel += new MyDelegate1(Sum);mulDel += new MyDelegate1(Sum);

mulDel(5, 10); mulDel(5, 10);

mulDel -= new MyDelegate1(Print);mulDel -= new MyDelegate1(Print);mulDel(5,10);mulDel(5,10);

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ProblemProblem

Xy d ng hm Sort t ng qut cho m ng i t ng c ki u b t

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