Get value from a Delegate in C#

Question

Hello,

How can I get value (here value is 100) from a delegate?

public delegate int MyDel(int x);
internal class Program
{
     static MyDel MyMethod(int x)
     {
          MyDel my = x => x * x;
          return my; //100
     }
     static void Main()
     {
          Console.WriteLine(MyMethod(10));
     }
}

Answer 1

Hi @Shervan360 , Welcome to Microsoft Q&A.

We generally don't use it like this: you can use the following two ways

using System;

namespace_6_20_x
{
     public delegate int MyDel(int x);
     internal class Program
     {
         static int Square(int x)
         {
             return x * x;
         }
         static void Main(string[] args)
         {
             MyDel myDelegate = new MyDel(Square); // Create a delegate instance and bind it to the Square method
             int result = myDelegate(10); // call the delegate instance, passing the parameter 10
             Console.WriteLine(result); // Output: 100
         }
     }
}

---

using System;

namespace _6_20_x
{
    public delegate int MyDel(int x);
    internal class Program
    {
        static void Main(string[] args)
        {
            MyDel myDelegate = x => x * x; // use lambda expression to create delegate instance
            int result = myDelegate(10); // call the delegate instance, passing the parameter 10
            Console.WriteLine(result); // Output: 100            
        }
    }
}

---

In your code, MyMethod(10) returns type MyDel. You have to nest one layer to get the value out.

using System;

public delegate int MyDel(int x);

internal class Program
{
    static MyDel MyMethod(int x)
    {
        MyDel my = y => y * y;
        return my;
    }

    static void Main(string[] args)
    {
        MyDel myDelegate = MyMethod(10);
        int result = myDelegate(0); // Invoking the delegate with any value (0 in this case)
        Console.WriteLine(result); // Output: 100
    }
}

Best Regards,

Jiale

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