#717 – Drag-and-Drop with Touch on Windows 7

You can implement drag-and-drop on a touch-based system in a similar way to how you implement drag-and-drop using the mouse.

You start by defining a handler for the TouchDown event of the control that serves as a drag source.  You then define a handler for the Drop event of the control that is the drop target.

    <StackPanel>
        <Label Content="Benjamin Disraeli"
               Background="AliceBlue" Margin="15" Padding="30,20" HorizontalAlignment="Center"
               TouchDown="Label_TouchDown"/>
        <Label Content="Drag to here"
               Background="Bisque" Margin="15" Padding="30,20" HorizontalAlignment="Center"
               AllowDrop="True" Drop="Label_Drop"/>
    </StackPanel>

In the code-behind, you call the DoDragDrop method to initiate drag-and-drop.

        // Drag source
        private void Label_TouchDown(object sender, TouchEventArgs e)
        {
            Label l = e.Source as Label;
            DragDrop.DoDragDrop(l, l.Content + " was Dragged!", DragDropEffects.Copy);
        }

        // Drag target
        private void Label_Drop(object sender, DragEventArgs e)
        {
            string draggedText = (string)e.Data.GetData(DataFormats.StringFormat);
            Label l = e.Source as Label;
            l.Content = draggedText;
        }

You can now touch and hold your finger down to drag.

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