public static void OnMouseDown(TreeViewItemEx tvItem, MouseButtonEventArgs e)
{
if (e.ButtonState == MouseButtonState.Pressed &&
(e.ChangedButton == MouseButton.Left || e.ChangedButton == MouseButton.Right))
{
dragInfo = new DragInfo(tvItem, e);
}
}
public static void OnMouseMove(TreeViewEx treeView, MouseEventArgs e)
{
if (dragInfo == null)
{
return;
}
if (dragInfo.ShouldCancel(e))
{
dragInfo = null;
}
else if (dragInfo.SouldStartDrag(e))
{
dragInfo.GatherSelectedItems(treeView);
if (dragInfo.CanStartDrag())
{
var dataObject = DataObjectGenerator.Genrate(dragInfo.SourceItems, includeObject: true);
if (dragInfo.DirectVisualSourceItem.Item.IsInEditMode)
{
dragInfo.DirectVisualSourceItem.Item.CommitEdit();
}
try
{
System.Diagnostics.Debug.WriteLine($"StartDrag: {dragInfo.DirectVisualSourceItem.Item}");
dragInfo.IsDragInProgress = true;
var result = System.Windows.DragDrop.DoDragDrop(treeView, dataObject, DragDropEffects.Move | DragDropEffects.Copy);
dragInfo.IsDragInProgress = false;
if (result != DragDropEffects.None)
{
HandleDropForSource(result);
}
}
finally
{
Cancel();
}
}
}
}
private static void Cancel()
{
dropInfo?.DropTargetAdorner?.Detach();
dropInfo = null;
dragInfo = null;
}