How to: Create a custom context menu

• Nov 28, 2019
• 2 minutes to read

The empty area does not provide a predefined context menu. You can handle the tree list’s PopupMenuShowing or MouseDown event to show a context menu in the empty area. The code below uses the MouseDown event that fires when a mouse button is pressed. The event handler adds the Add Node command that creates a new node. For an example of how to handle the PopupMenuShowing event, see Empty Area Context Menu.

The TreeList.CalcHitInfo method in the event handler returns internal information about the clicked visual element. If the empty area is clicked, the menu is created and the Add Node command is added to the menu. The DXMenuItem.Click event handler creates a new node.

C#

using DevExpress.Utils.Menu;
using DevExpress.XtraTreeList;
using DevExpress.XtraTreeList.Menu;
using DevExpress.XtraTreeList.Nodes;

private void treeList1_MouseDown(object sender, MouseEventArgs e) {
    TreeListHitInfo hitInfo = treeList1.CalcHitInfo(e.Location);
    TreeListNode node = null;
    if (hitInfo.HitInfoType == HitInfoType.Empty) {
        // Create a menu with the Add Node command.
        TreeListMenu menu = new TreeListMenu(sender as TreeList);
        DXMenuItem menuItem = new DXMenuItem("Add Node", new EventHandler(addNodeMenuItemClick));
        menu.Items.Add(menuItem);
        // Show the menu.
        menu.Show(e.Location);
    }
}

private void addNodeMenuItemClick(object sender, EventArgs e) {
    treeList1.Nodes.Add("555", "555", "555", "New Department", "10000", "New Location");
}

VB.NET

Imports DevExpress.Utils.Menu
Imports DevExpress.XtraTreeList
Imports DevExpress.XtraTreeList.Menu
Imports DevExpress.XtraTreeList.Nodes

Private Sub treeList1_MouseDown(ByVal sender As Object, ByVal e As MouseEventArgs) Handles treeList1.MouseDown
    Dim hitInfo As TreeListHitInfo = treeList1.CalcHitInfo(e.Location)
    Dim node As TreeListNode = Nothing
    If hitInfo.HitInfoType = HitInfoType.Empty Then
        ' Create a menu with the Add Node command.
        Dim contextMenu As New TreeListMenu(TryCast(sender, TreeList))
        Dim menuItem As New DXMenuItem("Add Node", New EventHandler(AddressOf addNodeMenuItemClick))
        contextMenu.Items.Add(menuItem)
        ' Show the menu.
        contextMenu.Show(e.Location)
    End If
End Sub

Private Sub addNodeMenuItemClick(ByVal sender As Object, ByVal e As EventArgs)
    treeList1.Nodes.Add("555", "555", "555", "New Department", "10000", "New Location")
End Sub

Tip

The example uses the DevExpress.XtraTreeList.Menu.TreeListMenu type that is a default type for tree list menus. You can also use a PopupMenu object that provides design-time customization capabilities.