Csharp/C Sharp/Language Basics/delegate anonymous

Anonymous methods can be assigned a signature

 
using System;
using System.Threading;

public delegate int DelegateClass(out int param);
public class Starter {
    public static void Main() {
        int var;
        DelegateClass del = delegate(out int inner) {
            inner = 12;
            Console.WriteLine("Running anonymous method");
            return inner;
        };
        del(out var);
        Console.WriteLine("Var is {0}", var);
    }
}

Anonymous methods can be assigned a signature, which is appended to the delegate keyword.

 
using System;
using System.Threading;

public delegate int DelegateClass(out int param);
public class Starter {
    public static void Main() {
        int var;
        DelegateClass del = delegate(out int inner) {
            inner = 12;
            Console.WriteLine("Running anonymous method");
            return inner;
        };
        del(out var);
        Console.WriteLine("Var is {0}", var);
    }
}

Anonymous methods can refer to local variables of the containing function and class members within the scope of the method definition

 
using System;
public delegate void DelegateClass(out int arg);
public class Starter {
    public static void Main() {
        DelegateClass del = MethodA();
        int var;
        del(out var);
        Console.WriteLine(var);
    }
    public static DelegateClass MethodA() {
        int local = 0;
        return delegate(out int arg) {
            arg = ++local;
        };
    }
}

Define an anonymous method with the delegate keyword.

 
using System;
using System.Threading;
public delegate void DelegateClass();
public class Starter {
    public static void Main() {
        DelegateClass del = delegate {
            Console.WriteLine("Running anonymous method");
        };
        del();
    }
}

Local variables used in an anonymous method are called outer variables.

 
using System;
public delegate void DelegateClass(out int arg);
public class Starter {
    public static void Main() {
        DelegateClass del = MethodA();
        int var;
        del(out var);
        Console.WriteLine(var);
    }
    public static DelegateClass MethodA() {
        int local = 0;
        return delegate(out int arg) {
            arg = ++local;
        };
    }
}

two delegates and anonymous methods

 
using System;

public delegate void ADelegate(int param);
public delegate int BDelegate(int param1, int param2);
public class Starter {
    public static void Main() {
        ADelegate del = delegate(int param) {
            param = 5;
        };
    }
    public int MethodA() {
        BDelegate del = delegate(int param1, int param2) {
            return 0;
        };
        return 0;
    }
}