TreeViewControl.ShowNodeMenu Event

Occurs before a user opens a node’s context menu and allows you to customize this menu.

Namespace: DevExpress.Xpf.Grid

Assembly: DevExpress.Xpf.Grid.v21.2.dll

NuGet Package: DevExpress.Wpf.Grid.Core

Declaration

C#

public event TreeViewShowNodeMenuEventHandler ShowNodeMenu

VB.NET

Public Event ShowNodeMenu As TreeViewShowNodeMenuEventHandler

Event Data

The ShowNodeMenu event's data class is TreeViewNodeMenuEventArgs. The following properties provide information specific to this event:

Property	Description
Customizations	Gets a collection of actions for the context menu.
Handled	Gets or sets a value that indicates the present state of the event handling for a routed event as it travels the route. Inherited from RoutedEventArgs.
Items	Gets a collection of context menu items.
Node	Gets a node for which the context menu is shown.
OriginalSource	Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs.
RoutedEvent	Gets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs.
Source	Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs.
TargetElement	Gets a UI element for which the context menu is shown.

The event data class exposes the following methods:

Method	Description
InvokeEventHandler(Delegate, Object)	When overridden in a derived class, provides a way to invoke event handlers in a type-specific way, which can increase efficiency over the base implementation. Inherited from RoutedEventArgs.
OnSetSource(Object)	When overridden in a derived class, provides a notification callback entry point whenever the value of the Source property of an instance changes. Inherited from RoutedEventArgs.

Remarks

Use the NodeMenuCustomizations property to add items to a node’s context menu.

The following code sample removes the Delete Node item from the context menu for root nodes:

XAML

<Window
        xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid" 
        xmlns:dxb="http://schemas.devexpress.com/winfx/2008/xaml/bars"
        ... >
  <dxg:TreeViewControl ...
                      ShowNodeMenu="treeview_ShowNodeMenu">
      <dxg:TreeViewControl.NodeMenuCustomizations>
          <dxb:BarButtonItem Name="deleteNode" Content="Delete Node"/>
          <dxb:BarButtonItem Name="copyNodeData" Content="Copy Node Data"/>
      </dxg:TreeViewControl.NodeMenuCustomizations>
  </dxg:TreeViewControl>

C#

void treeview_ShowNodeMenu(object sender, DevExpress.Xpf.Grid.TreeList.TreeViewNodeMenuEventArgs e) {
    if (e.Node.Level == 0) e.Customizations.Add(new RemoveAction { ElementName = "deleteNode"} );
}

VB.NET

Private Sub treeview_ShowNodeMenu(ByVal sender As Object, ByVal e As DevExpress.Xpf.Grid.TreeList.TreeViewNodeMenuEventArgs)
    If e.Node.Level = 0 Then e.Customizations.Add(New RemoveAction With {
        .ElementName = "deleteNode"
    })
End Sub