Common in C # system built-in delegate usage detailed (transcription)

Common system built-in delegates in C #

Action class, Func class, predicate<t>, Comparison<t> delegate

• Delegate for Action class

2. The action delegate encapsulates a method that does not have parameters and does not return a value

4. The Action<t> delegate encapsulates a method that has only one parameter and does not return a value

6. The Action<t1,t2> delegate encapsulates a method that has two parameters and does not return a value

7. Static voidMain (string[] args) {#regionAction<t> Delegate Example//Requirements: Print out the elements of the integer collection listlist<int> list =Newlist<int> () {1,2,3,4,5 }; //assigning an anonymous method to a action<t> delegate instanceaction<int> CONCAT1 =Delegate(inti) {Console.WriteLine (i);}; List.  ForEach (CONCAT1); //Assigning a lambda expression to an action<t> delegate instanceaction<int> concat2 = (i =Console.WriteLine (i)); List.  ForEach (CONCAT2);　　Console.readkey (); #endregion }

• Delegate for the Func class

2. 1.Func (TResult) delegate encapsulates a method that encapsulates a type value that does not have a parameter but returns the TResult parameter
4. The Func (T,tresult) delegate encapsulates a method that has a parameter and returns the type value specified by the TResult parameter
6. The Func (T1,t2,tresult) delegate encapsulates a method that has two parameters and returns the type value specified by the TResult parameter

7. Static voidMain (string[] args) {  #regionFunc<t,tresult> Delegate Example//requirement: Finds a new collection of all elements greater than 3 in the list of integral types and prints out the collection elementslist<int> list =Newlist<int> () {1,2,3,4,5 }; //assigning an anonymous method to a func<t,tresult> delegate instancefunc<int,BOOL> CONCAT1 =Delegate(inti) {returni >3; }; varNewlist1 =list. Where (CONCAT1).  ToList (); //Assigning a LAMBDA expression to an func<t,tresult> delegate instancefunc<int,BOOL> concat2 = i = i >3; varNewlist2 =list. Where (CONCAT2).  ToList (); Newlist1. ForEach (i=Console.WriteLine (i.ToString ())); Newlist2. ForEach (i=Console.WriteLine (i.ToString ()));  Console.readkey (); #endregion}

• Predicate<t> delegate

Represents a method that defines a set of conditions and determines whether the specified object conforms to these conditions

1. Static voidMain (string[] args) {  #regionPredicate<t> Delegate Example//requirement: Finds a new collection of all elements greater than 3 in the list of integral types and prints out the collection elementslist<int> list =Newlist<int> () {1,2,3,4,5 }; //assigning an anonymous method to a predicate<t> delegate instancepredicate<int> CONCAT1 =Delegate(inti) {returni >3; }; varNewlist1 =list.  FindAll (CONCAT1); //Assigning a lambda expression to an predicate<t> delegate instancepredicate<int> CONCAT2 = (c = c >3); varNewlist2 =list.  FindAll (CONCAT2); Newlist1. ForEach (i=Console.WriteLine (i)); Newlist2. ForEach (i=Console.WriteLine (i));  Console.readkey (); #endregion}

• Comparison<t> delegate

Represents a method that compares two objects of the same type

• Static voidMain (string[] args) {  #regionComparison<t> Delegate Example//Requirement: Prints all elements in the list of integral types in reverse orderlist<int> list =Newlist<int> () {1,2,3,4,5 }; //assigning an anonymous method to a comparison<t> delegate instancecomparison<int> CONCAT1 =Delegate(intIintj) {returnJ-i;}; //Assigning a lambda expression to an comparison<t> delegate instancecomparison<int> CONCAT2 = (i, j) + J-i; List.  Sort (CONCAT1); List. ForEach (c=Console.WriteLine (C.tostring ())); List.  Sort (CONCAT2); List. ForEach (c=Console.WriteLine (C.tostring ()));  Console.readkey (); #endregion}

Common in C # system built-in delegate usage detailed (transcription)