Compiler Error CS1061

'type' does not contain a definition for 'name' and no accessible extension method 'name' accepting a first argument of type 'type' could be found (are you missing a using directive or an assembly reference?).

This error occurs when you try to call a method or access a class member that does not exist.

Example

The following example generates CS1061 because Person does not have a DisplayName method. It does have a method that is called WriteName. Perhaps that is what the author of this source code meant to write.

public class Person
{
    private string _name;

    public Person(string name) => _name = name;

    // Person has one method, called WriteName.
    public void WriteName()
    {
        System.Console.WriteLine(_name);
    }
}

public class Program
{
    public static void Main()
    {
        var p = new Person("PersonName");

        // The following call fails because Person does not have
        // a method called DisplayName.
        p.DisplayName(); // CS1061
    }
}

To correct this error

• Make sure you typed the member name correctly.
• If you have access to modify this class, you can add the missing member and implement it.
• If you don't have access to modify this class, you can add an extension method.
• If the member you're trying to access should exist but doesn't, you might be missing a required NuGet package. Search NuGet.org to find packages that contain the missing member.

See also

• The C# type system
• Extension Methods