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How to stop drag drop a document tab to specified position?
1 min read
In DockingManager, the following code example describes you how to stop a drag drop document tab on desire position. For Example, here you can avoid dropping on 0th position. In PreviewDrop event of document container, check the Index of the target item, if the target item is 0, then handle the event.
XAML
<syncfusion:DockingManager Name="dockingmanager" UseDocumentContainer="True"> <ContentControl Content="Document" syncfusion:DockingManager.State="Document" syncfusion:DockingManager.Header="Document1"> </ContentControl> <ContentControl Content="Document" syncfusion:DockingManager.State="Document" syncfusion:DockingManager.Header="Document2"> </ContentControl> <ContentControl Content="Document" syncfusion:DockingManager.State="Document" syncfusion:DockingManager.Header="Document3"> </ContentControl> </syncfusion:DockingManager>
C#
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
(dockingmanager.DocContainer as DocumentContainer).PreviewDrop += MainWindow_PreviewDrop;
}
void MainWindow_PreviewDrop(object sender, DragEventArgs e)
{
DocumentTabControl tabcontrol = VisualUtils.FindDescendant(sender as Visual, typeof(DocumentTabControl)) as DocumentTabControl;
if (tabcontrol != null)
{
TabItemExt tabitem = VisualUtils.FindAncestor(e.OriginalSource as Visual, typeof(TabItemExt)) as TabItemExt;
if (tabitem != null)
{
int location = tabcontrol.Items.IndexOf(tabitem);
// Check the index position based on our requirement
if (location == 0)
{
// Getting Find Decendant to collapsed the adorner after handling the drop
InsertionAdorner adorner = FindDescendant(tabcontrol, typeof(InsertionAdorner)) as InsertionAdorner;
if (adorner != null)
{
adorner.Visibility = Visibility.Collapsed;
(sender as DocumentContainer).ShowDragAdorner = false;
}
e.Handled = true;
}
}
}
}
public static Visual FindDescendant(Visual startingFrom, Type typeDescendant)
{
Visual visual = null;
bool result = false;
int iCount = VisualTreeHelper.GetChildrenCount(startingFrom);
for (int i = 0; i < iCount; ++i)
{
Visual child = VisualTreeHelper.GetChild(startingFrom, i) as Visual;
if (typeDescendant.IsInstanceOfType(child) && (child as UIElement) != null && (child as UIElement).Visibility==Visibility.Visible)
{
visual = child;
result = true;
}
if (!result)
{
if (child != null)
{
visual = FindDescendant(child, typeDescendant);
if (visual != null)
{
break;
}
}
}
else
{
break;
}
}
return visual;
}
}