Question

I am trying to move control in wpf using Canvas

This is the XAML

    <Canvas Grid.Column="1" Grid.Row="0" x:Name="DropCanvas"   AllowDrop="True"  DragOver="DropCanvas_DragOver" 
            Drop="Canvas_Drop" DragEnter="Canvas_DragEnter" Background="#12000000" >
        <TextBox Canvas.Left="162" Canvas.Top="188" Height="23" Name="textBox1" Width="120"  
                 PreviewMouseMove="textBox1_PreviewMouseMove" 
                 PreviewMouseLeftButtonDown="textBox1_PreviewMouseLeftButtonDown" 
                 PreviewMouseUp="textBox1_PreviewMouseUp" />
    </Canvas>

and this is the Code

    Point p = new Point();
    private void textBox1_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        Control control = sender as Control;

        control.CaptureMouse();
        p = e.GetPosition(control);   
    }

    private void textBox1_PreviewMouseMove(object sender, MouseEventArgs e)
    {       
            Control control = sender as Control;
            Point x = e.GetPosition(control);
            if (e.LeftButton == MouseButtonState.Pressed)
            {
                Canvas.SetLeft(control, Canvas.GetLeft(control) + (x.X - p.X));
                Canvas.SetTop(control, Canvas.GetTop(control) + (x.Y - p.Y));
            }
            p = x;          
    }

    private void textBox1_PreviewMouseUp(object sender, MouseButtonEventArgs e)
    {
        Control control = sender as Control;
        control.ReleaseMouseCapture();

        activated = false;        
    }

The code is working, but when it moves, the control shakes.
What is the proplem

Answer 1

When you call GetPosition you should use DropCanvas as the parameter instead of the control. You’re seeing vibrations because the TextBox keeps moving and you need something fixed.

Alternatively, you can use the MouseDragElementBehavior available in Expression Blend SDK to move objects in a container.

Also, this project can be useful to you: http://www.codeproject.com/Articles/24681/WPF-Diagram-Designer-Part-4