Compiler Error CS1628

  • Article

Cannot use ref or out parameter 'parameter' inside an anonymous method, lambda expression, or query expression

This error occurs if you use a ref or out parameter inside an anonymous method block. To avoid this error, use a local variable or some other construct.

The following sample generates CS1628:

// CS1628.cs

delegate int MyDelegate();

class C
{
  public static void F(ref int i)
  {
      MyDelegate d = delegate { return i; };  // CS1628
      // Try this instead:
      // int tmp = i;
      // MyDelegate d = delegate { return tmp; };
  }

  public static void Main()
  {
     
  }
}