Pass a Method as a Parameter in C# Function

1. Use Func Delegate to Pass a Method as a Parameter in C#
2. Use Action Delegate to Pass a Method as a Parameter in C#

This article will introduce different methods to pass a method as a parameter in C# function.

• Using Func delegate
• Using Action delegate

Use Func Delegate to Pass a Method as a Parameter in C#

We will use the built-in delegate Func to pass a method as a parameter. A delegate acts like a function pointer. The correct syntax to use this delegate is as follows.

public delegate returnType Func<in inputType, out returnType>(InputType arg);

The built-in delegate Func has N parameters. The details of its parameters are as follows.

The program below shows how we can use the Func delegate to pass a method as a parameter.

public class MethodasParameter
{
    public int Method1(string input)
    {
        return 0;
    }

    public int Method2(string input)
    {
        return 1;
    }

    public bool RunMethod(Func<string, int> MethodName)
    {
        int i = MethodName("This is a string");
        return true;
    }

    public bool Test()
    {
        return RunMethod(Method1);
    }
}

Use Action Delegate to Pass a Method as a Parameter in C#

We can also use the built-in delegate Action to pass a method as a parameter. The correct syntax to use this delegate is as follows.

public delegate void Action<in T>(T obj);

The built-in delegate Action can have 16 parameters as input. The details of its parameters are as follows.

The program below shows how we can use the Action delegate to pass a method as a parameter.

public class MethodasParameter
{
    public int Method1(string input)
    {
        return 0;
    }

    public int Method2(string input)
    {
        return 1;
    }

    public bool RunTheMethod(Action myMethodName)
 {
      myMethodName();
      return true;
 }
  RunTheMethod(() => Method1("MyString1"));
}