DragMove() and Maximize

Question

I have a problem with my custom window (AllowTransparency, WindowStyle=None) in WPF. DragMove() method works good, but when I maximize window, or it maximizing automatically

Answer 1

Groaner's solution does not function properly with multiple monitor setups, especially where the primary monitor is not the left-most.

Here is my solution based on his which handles single or multiple monitor setups properly. In this code 'rctHeader' is a Rectangle defined in the XAML.

    private bool mRestoreIfMove = false;


    public MainWindow()
    {
        InitializeComponent();
    }


    private void SwitchWindowState()
    {
        switch (WindowState)
        {
            case WindowState.Normal:
                {
                    WindowState = WindowState.Maximized;
                    break;
                }
            case WindowState.Maximized:
                {
                    WindowState = WindowState.Normal;
                    break;
                }
        }
    }


    private void rctHeader_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        if (e.ClickCount == 2)
        {
            if ((ResizeMode == ResizeMode.CanResize) || (ResizeMode == ResizeMode.CanResizeWithGrip))
            {
                SwitchWindowState();
            }

            return;
        }

        else if (WindowState == WindowState.Maximized)
        {
            mRestoreIfMove = true;
            return;
        }

        DragMove();
    }


    private void rctHeader_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
    {
        mRestoreIfMove = false;
    }


    private void rctHeader_MouseMove(object sender, MouseEventArgs e)
    {
        if (mRestoreIfMove)
        {
            mRestoreIfMove = false;

            double percentHorizontal = e.GetPosition(this).X / ActualWidth;
            double targetHorizontal = RestoreBounds.Width * percentHorizontal;

            double percentVertical = e.GetPosition(this).Y / ActualHeight;
            double targetVertical = RestoreBounds.Height * percentVertical;

            WindowState = WindowState.Normal;

            POINT lMousePosition;
            GetCursorPos(out lMousePosition);

            Left = lMousePosition.X - targetHorizontal;
            Top = lMousePosition.Y - targetVertical;

            DragMove();
        }
    }



    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    static extern bool GetCursorPos(out POINT lpPoint);


    [StructLayout(LayoutKind.Sequential)]
    public struct POINT
    {
        public int X;
        public int Y;

        public POINT(int x, int y)
        {
            this.X = x;
            this.Y = y;
        }
    }


}