A draggable popup control in wpf - wpf

Question

I need a draggable popup control in wpf and was wondering if any of your guys could help me out..I did see the following post:
Drag WPF Popup control
but that isnt how its supposed to work...? When i click and drag it always resets to a specific point and moreover the commenters said that this is not an efficient approach...?
Does anyone have any alternatives?
Thanks!

Answer 1

We can write a behavior to make any Popup draggable. Here is some sample XAML of a popup associated with a textbox that opens and stays open when the text box is focused:
<Grid>
<StackPanel>
<TextBox x:Name="textBox1" Width="200" Height="20"/>
</StackPanel>
<Popup PlacementTarget="{Binding ElementName=textBox1}" IsOpen="{Binding IsKeyboardFocused, ElementName=textBox1, Mode=OneWay}">
<i:Interaction.Behaviors>
<local:MouseDragPopupBehavior/>
</i:Interaction.Behaviors>
<TextBlock Background="White">
<TextBlock.Text>Sample Popup content.</TextBlock.Text>
</TextBlock>
</Popup>
</Grid>
Here is the behavior that allows us to drag the Popup:
public class MouseDragPopupBehavior : Behavior<Popup>
{
private bool mouseDown;
private Point oldMousePosition;
protected override void OnAttached()
{
AssociatedObject.MouseLeftButtonDown += (s, e) =>
{
mouseDown = true;
oldMousePosition = AssociatedObject.PointToScreen(e.GetPosition(AssociatedObject));
AssociatedObject.Child.CaptureMouse();
};
AssociatedObject.MouseMove += (s, e) =>
{
if (!mouseDown) return;
var newMousePosition = AssociatedObject.PointToScreen(e.GetPosition(AssociatedObject));
var offset = newMousePosition - oldMousePosition;
oldMousePosition = newMousePosition;
AssociatedObject.HorizontalOffset += offset.X;
AssociatedObject.VerticalOffset += offset.Y;
};
AssociatedObject.MouseLeftButtonUp += (s, e) =>
{
mouseDown = false;
AssociatedObject.Child.ReleaseMouseCapture();
};
}
}
If you are not familiar with behaviors, install the Expression Blend 4 SDK and add this namespaces:
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
and add System.Windows.Interactivity to your project.

Answer 2

You could open a child Window with a custom border layout. Then add a MouseDown handler that enables the dragging:
<Window
WindowStyle="None"
ShowInTaskbar="False"
ResizeMode="NoResize"
SizeToContent="Height"
MouseDown="Window_MouseDown">
...
</Window>
In code behind:
private void Window_MouseDown(Object sender, MouseButtonEventArgs e)
{
this.DragMove();
}