CreatePopupMenu() with api

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C#

API

Hi i want to know how can i use the createpopupmenu() with api, i write class like this:

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;

namespace test
{
  
        [DllImport("user32.dll")]
        public static extern int DestroyIcon(IntPtr hIcon);

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public extern static bool ShowWindow(IntPtr hWnd, int nCmdShow);

        public const int GWL_EXSTYLE = -20;
        public const int WM_CLOSE = 16;
        public const int WM_COPY = 0x0301;
        public const int WM_PASTE = 0x0302;
        public const int WM_CUT = 0x0300;
        public const int WM_ERASEBKGND = 0x0014;
        public const int WM_USER = 0x400;
        public const int WM_DEVICECHANGE = 0x219;

        public const int EM_GETSCROLLPOS = (WM_USER + 221);
        public const int EM_SETSCROLLPOS = (WM_USER + 222);

        [DllImport("user32.dll")]
        public static extern IntPtr SetWindowLong(IntPtr hWnd, Int32 nIndex, IntPtr dwNewLong);

        [DllImport("user32.dll")]
        public static extern IntPtr GetSystemMenu(IntPtr hWnd, bool bRevert);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
        public static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
        public static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, ref POINT point);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);

        [DllImport("user32.dll")]
        public static extern IntPtr CreatePopupMenu();

        [DllImport("user32", SetLastError = true, CharSet = CharSet.Auto)]
        public static extern bool InsertMenu(IntPtr hmenu, int position, uint flags, IntPtr item_id, [MarshalAs(UnmanagedType.LPTStr)]string item_text);

        [Flags]
        public enum MenuFlags : uint
        {
            MF_STRING = 0,
            MF_BYPOSITION = 0x400,
            MF_SEPARATOR = 0x800,
            MF_REMOVE = 0x1000,
            MF_POPUP = 0x00000010,
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct POINT
        {
            public int x;
            public int y;
        }
    }
}

but i try to use this class and createpopupmenu() method to make menu for my form but it wont work ...? can any one guid me what am i do...?
tnx