Delphi Prism getting Unknown Identifier “DllImport” error

Question

I'm trying to call Window's SendMessage method in Delphi Prism, I've declared the class as follow:

type
  MyUtils = public static class
  private
    [DllImport("user32.dll", CharSet := CharSet.Auto)]
    method SendMessage(hWnd:IntPtr; Msg:UInt32; wParam:IntPtr; lParam:IntPtr):IntPtr; external;
  protected
  public
  end;

When I tried to compile, I get the error Unknown identifier "DllImport"

I used this as an example, How to call function CreateProcess in Delphi Prism? and the syntax looks the same. Is there a setting I need to enable, or do I have a syntax error?

Answer 1

Make sure you import (use) System.Runtime.InteropServices. That's where the DllImport attribute is defined.