private void TVI_DragLeave(object sender, DragEventArgs e)
{
this.adorner?.Remove();
adorner = null;
e.Handled = true;
Debug.WriteLine("TVI DragLeave");
}
private void TVI_DragEnter(object sender, DragEventArgs e)
{
if (DragDropController?.CanDrop == null)
{
return;
}
var tvi = sender as TreeViewItem;
var ti = tvi.DataContext as TreeItem;
if (this.adorner == null)
{
var mousePos = e.GetPosition(tvi);
var header = tvi.Template.FindName("PART_Header", tvi) as FrameworkElement;
var heightHeader = header?.ActualHeight ?? tvi.ActualHeight;
var draggedTreeItem = e.Data.GetData(typeof(TreeItem));
var yPercentage = mousePos.Y * 100 / heightHeader;
this.adorner = new TreeItemDragOverAdorner(header, yPercentage);
}
Debug.WriteLine($"DragEnter {ti.Data}, Effects: {e.Effects}");
// keine weitere Aktion
e.Handled = true;
}
private void TVI_MouseMove(object sender, MouseEventArgs e)
{
if (DragDropController?.CanDrag == null)
{
return;
}
TreeViewItem tvi = sender as TreeViewItem;
// Ist die Maus vielleicht bereits auf ein anderes Item gerutscht?
if (tvi != treeViewItemToDrag)
{
return;
}
isDragging = e.GetPosition(this) != startposition;
var ti = tvi.DataContext as TreeItem;
// Rahmenbedingungen für DragDrop-Start prüfen
if (e.LeftButton == MouseButtonState.Pressed && isDragging && DragDropController.CanDrag(ti))
{
Debug.WriteLine($"DragDrop starting: {ti}");
ScrollUpBtn.Visibility = Visibility.Visible;
ScrollDownBtn.Visibility = Visibility.Visible;
// DoDragDrop kehrt erst nach Abschluss der Aktion wieder zurück
DragDrop.DoDragDrop(tvi, ti, DragDropEffects.All);
// fertig
ScrollUpBtn.Visibility = Visibility.Collapsed;
ScrollDownBtn.Visibility = Visibility.Collapsed;
this.adorner?.Remove();
adorner = null;
customCursor = null;
Debug.WriteLine($"DragDrop completed: {ti}");
}
}
private void TVI_Drop(object sender, DragEventArgs e)
{
if (DragDropController?.Drop == null)
{
return;
}
var tvi = sender as TreeViewItem;
var ti = tvi.DataContext as TreeItem;
var mousePos = e.GetPosition(tvi);
var header = tvi.Template.FindName("PART_Header", tvi) as FrameworkElement;
var heightHeader = header?.ActualHeight ?? tvi.ActualHeight;
this.adorner?.Remove();
adorner = null;
customCursor = null;
var draggedTreeItem = e.Data.GetData(typeof(TreeItem));
DragDropController.Drop(draggedTreeItem, ti, mousePos.Y * 100 / heightHeader);
e.Handled = true;
}
