Compiler Error CS0428

Cannot convert method group 'Identifier' to non-delegate type 'type'. Did you intend to invoke the method?

This error occurs when converting a method group to a non-delegate type, or attempting to invoke a method without using parentheses.

Example

The following sample generates CS0428:

// CS0428.cs
namespace ConsoleApplication1
{
    class Program
    {
        delegate int Del1();
        delegate object Del2();

        static void Main(string[] args)
        {
            ExampleClass ec = new ExampleClass();

            // The following assignment statement causes compiler error CS0428.
            // It attempts to assign the address of Method1 to an integer variable. 
            // You can only assign the address to an appropriate delegate type. 
            int i = ec.Method1;

            // Del1 is a delegate type that is appropriate for a method like 
            // Method1 that returns an int. The following assignment statement
            // does not cause an error.
            Del1 d1 = ec.Method1;

            // You can invoke Method1 and assign the int that is returned to 
            // integer variable i.
            i = ec.Method1();

            // The following assignment statement causes compiler error CS0428.
            // It attempts to assign the address of Method2 to an instance of 
            // ExampleClass. You can only assign the address to a delegate type. 
            ec = ExampleClass.Method2; 

            // Del2 is a delegate type that is appropriate for a method like 
            // Method2 that returns an instance of a class. The following assignment
            // statement does not cause an error.
            Del2 d2 = ExampleClass.Method2;

            // Similarly, you can invoke Method2 and assign the result returned to ec.
            ec = ExampleClass.Method2();
        }
    }

    public class ExampleClass
    {
        public int Method1() { return 1; }
        public static ExampleClass Method2() { return null; }
    }
}

Change History

Date	History	Reason
August 2009	Expanded the example.	Customer feedback.