public void listView_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
if (this.IsMouseOverScrollbar)
{
// 4/13/2007 - Set the flag to false when cursor is over scrollbar.
this.canInitiateDrag = false;
return;
}
int index = this.IndexUnderDragCursor;
this.canInitiateDrag = index > -1;
if (this.canInitiateDrag)
{
// Remember the location and index of the ListViewItem the user clicked on for later.
this.ptMouseDown = MouseUtilities.GetMousePosition(this.listView);
this.indexToSelect = index;
}
else
{
this.ptMouseDown = new Point(-10000, -10000);
this.indexToSelect = -1;
}
}
bool IsMouseOver(Visual target)
{
// We need to use MouseUtilities to figure out the cursor
// coordinates because, during a drag-drop operation, the WPF
// mechanisms for getting the coordinates behave strangely.
Rect bounds = VisualTreeHelper.GetDescendantBounds(target);
Point mousePos = MouseUtilities.GetMousePosition(target);
return(bounds.Contains(mousePos));
}
void UpdateDragAdornerLocation()
{
if (this.dragAdorner != null)
{
Point ptCursor = MouseUtilities.GetMousePosition(this.ListView);
double left = ptCursor.X - this.ptMouseDown.X;
// 4/13/2007 - Made the top offset relative to the item being dragged.
ListViewItem itemBeingDragged = this.GetListViewItem(this.indexToSelect);
Point itemLoc = itemBeingDragged.TranslatePoint(new Point(0, 0), this.ListView);
double top = itemLoc.Y + ptCursor.Y - this.ptMouseDown.Y;
this.dragAdorner.SetOffsets(left, top);
}
}
AdornerLayer InitializeAdornerLayer(ListViewItem itemToDrag)
{
// Create a brush which will paint the ListViewItem onto
// a visual in the adorner layer.
VisualBrush brush = new VisualBrush(itemToDrag);
// Create an element which displays the source item while it is dragged.
this.dragAdorner = new DragAdorner(this.listView, itemToDrag.RenderSize, brush);
// Set the drag adorner's opacity.
this.dragAdorner.Opacity = this.DragAdornerOpacity;
AdornerLayer layer = AdornerLayer.GetAdornerLayer(this.listView);
layer.Add(dragAdorner);
// Save the location of the cursor when the left mouse button was pressed.
this.ptMouseDown = MouseUtilities.GetMousePosition(this.listView);
return(layer);
}
