c# - Move a borderless window in wpf

Question

In my C# WinForms app I have a main window that has its default controls hidden.

So to allow me to move it around I added the following to the main window:

private const int WM_NCHITTEST = 0x84;
private const int HTCLIENT = 0x1;
private const int HTCAPTION = 0x2;
private const int WM_NCLBUTTONDBLCLK = 0x00A3;

protected override void WndProc(ref Message message)
{
    if (message.Msg == WM_NCLBUTTONDBLCLK)
    {
        message.Result = IntPtr.Zero;
        return;
    }

    base.WndProc(ref message);

    //Allow window to move
    if (message.Msg == WM_NCHITTEST && (int)message.Result == HTCLIENT)
        message.Result = (IntPtr)HTCAPTION;
}

I have a WPF App where I have also hidden the default controls and I want to do the same. I see that the main window is derived from a 'Window' so the above code does not work. How do I do this in WPF?

Answer 1

To do this you will want to attach an event handler to the MouseDown event of the window, check that the left mouse button was pressed and call the DragMove method on the window.

Here is a sample of a window with this functionality:

public partial class MyWindow : Window
{
    public MyWindow()
    {
        InitializeComponent();
        MouseDown += Window_MouseDown;
    }

    private void Window_MouseDown(object sender, MouseButtonEventArgs e)
    {
        if (e.ChangedButton == MouseButton.Left)
            DragMove();
    }
}