Compiler Error CS1501

No overload for method 'method' takes 'number' arguments

A call was made to a class method, but there is no form of the method that takes the necessary number of arguments.

CS1501 could occur if you are calling a method on a class in a referenced assembly and if that method has default values on one or more of its parameters. C# does not let you create methods with a default value on a parameter, but another language that targets the runtime might. If a parameter (in a method in a referenced assembly) has a default value, you must still call the method and explicitly pass all parameters.

Example

The following sample generates CS1501.

using System;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            ExampleClass ec = new ExampleClass();
            ec.ExampleMethod();
            ec.ExampleMethod(10);
            // The following line causes compiler error CS1501 because 
            // ExampleClass does not contain an ExampleMethod that takes
            // two arguments.
            ec.ExampleMethod(10, 20);
        }
    }

    // ExampleClass defines two methods, one that has no parameters and
    // one that has a single parameter.
    class ExampleClass
    {
        public void ExampleMethod()
        {
            Console.WriteLine("Zero parameters");
        }

        public void ExampleMethod(int i)
        {
            Console.WriteLine("One integer parameter.");
        }
    }
}

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