IconHelper.cs

using System;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;

namespace C2Windows
{
    public static class IconHelper
    {
        [DllImport("user32.dll")]
        static extern int GetWindowLong(IntPtr hwnd, int index);

        [DllImport("user32.dll")]
        static extern int SetWindowLong(IntPtr hwnd, int index, int newStyle);

        [DllImport("user32.dll")]
        static extern bool SetWindowPos(IntPtr hwnd, IntPtr hwndInsertAfter,
            int x, int y, int width, int height, uint flags);

        [DllImport("user32.dll")]
        static extern IntPtr SendMessage(IntPtr hwnd, uint msg,
            IntPtr wParam, IntPtr lParam);

        const int GWL_EXSTYLE = -20;
        const int WS_EX_DLGMODALFRAME = 0x0001;
        const int SWP_NOSIZE = 0x0001;
        const int SWP_NOMOVE = 0x0002;
        const int SWP_NOZORDER = 0x0004;
        const int SWP_FRAMECHANGED = 0x0020;
        const uint WM_SETICON = 0x0080;

        public static void RemoveIcon(Window window)
        {
            // Get this window's handle
            IntPtr hwnd = new WindowInteropHelper(window).Handle;

            // Change the extended window style to not show a window icon
            int extendedStyle = GetWindowLong(hwnd, GWL_EXSTYLE);
            SetWindowLong(hwnd, GWL_EXSTYLE, extendedStyle | WS_EX_DLGMODALFRAME);

            // Update the window's non-client area to reflect the changes
            SetWindowPos(hwnd, IntPtr.Zero, 0, 0, 0, 0, SWP_NOMOVE |
                  SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED);
        }
    }
}