Compiler Error CS1001


Updated: July 20, 2015

For the latest documentation on Visual Studio 2017 RC, see Visual Studio 2017 RC Documentation.

Identifier expected

You did not supply an identifier. An identifier is the name of a class, struct, namespace, method, variable and so on that you provide.

The following example declares a simple class but does not give the class a name:

public class              //CS1001  
        public int Num {get; set;}  
        void MethodA(){}  

The following sample generates CS1001 because, when declaring an enum, you must specify members:

// CS1001.cs  
public class clx  
   enum Colors : int  
      'a', 'b' // CS1001, 'a' is not a valid int identifier  
       // The following line shows examples of valid identifiers:  
       // Blue, Red, Orange  
   public static void Main()  

Parameter names are required even if the compiler doesn't use them, for example, in an interface definition. These parameters are required so that programmers who are consuming the interface know something about the what the parameters mean.

// CS1001-2.cs  
// compile with: /target:library  
interface IMyTest  
   void TestFunc1(int, int);  // CS1001  
   // Use the following line instead:  
   // void TestFunc1(int a, int b);  
class CMyTest : IMyTest  
   void IMyTest.TestFunc1(int a, int b)  

Statements, Expressions, and Operators