C#基础之委托

委托
委托让我们可以把函数引用保存在变量中。这就像在 C++ 中使用 typedef保存函数指针一样。
委托使用关键字 delegate 声明。看看这个例子,你就能理解什么是委托:例子:

delegate int Operation(int val1, int val2);
public int Add(int val1, int val2)
{
return val1 + val2;
}
public int Subtract (int val1, int val2)
{
return val1- val2;
}
public void Perform(){
Operation Oper;
Console.WriteLine("Enter + or - ");
string optor = Console.ReadLine();
Console.WriteLine("Enter 2 operands");
string opnd1 = Console.ReadLine();
string opnd2 = Console.ReadLine();
int val1 = Convert.ToInt32 (opnd1);
int val2 = Convert.ToInt32 (opnd2);
if (optor == "+")
Oper = new Operation(Add);
else
Oper = new Operation(Subtract);
Console.WriteLine(" Result = {0}", Oper(val1, val2));
}