Moveable Custom Control

问题:

I have a custom control and I want the user to be able to drag it. So I put in the following code in the custom control:

    void MoveableStackPanel_MouseMove(object sender, MouseEventArgs e)
    {
        if (IsMoving)
        {
            Point newLoc = e.GetPosition(null);
            MainWindow.Instance.Title = newLoc.ToString(); // Debug
            Margin = new Thickness(newLoc.X - 48, newLoc.Y - 48, 0, 0);
        }
    }

Note the "-48" in the code. When the mouse is moved up or left then the mouse is not in the controls area anymore and thus does no longer trigger the MouseMove event. So I added the -48 twice to work around that. But when the user moves the mouse faster than the framework can update then the mouse will get outside the controls area and the control also won't move anymore.

I was thinking about assigning an IMovableInterface and keep lists of controls that are moving in the main form and such but that is all such a hassle and such... What is the proper solution?

P.S.: the controls are generated dynamically so I need the solution in C# code and not in XML.

回答1:

Try using the CaptureMouse Method.

See if something like this works for you.:

void moveableStackPanel1_MouseUp(object sender, MouseButtonEventArgs e)
    {
        ReleaseMouseCapture();
    }

    void moveableStackPanel1_MouseDown(object sender, MouseButtonEventArgs e)
    {
        if (IsEnabled && IsVisible)
            CaptureMouse();
    }

    void moveableStackPanel1_MouseMove(object sender, MouseEventArgs e)
    {
        if (IsMouseCaptured)
        {
            Point newLoc = e.GetPosition(null);
            Margin = new Thickness(newLoc.X, newLoc.Y, 0, 0);
        }
    }