Removing Icon from a WPF window

Just add this WindowStyle="ToolWindow" to your window properties.

From WPFTutorial:

How to remove the icon of a WPF window

Unfortunately WPF does not provide any function to remove the icon of a window. One solution could be setting the icon to a transparent icon. But this way the extra space between the window border and title remains.

The better approach is to use a function provided by the Win32 API to remove the icon.

public partial class Window1 : Window
{
    public Window1()
    {
        InitializeComponent();
    }

    protected override void OnSourceInitialized(EventArgs e)
    {
        IconHelper.RemoveIcon(this);
    }
}

A helper class used to remove the icon.

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);
    }
}