Empty Area Context Menu

• Apr 30, 2020
• 2 minutes to read

The control can show a context menu when a user right-clicks the area below nodes. The default context menu for this area does not contain commands.

Populate the Menu

The PopupMenuShowing event is raised before the control shows a context menu. Handle this event to populate the menu with commands. Use the HitInfo event argument to get the clicked visual element. If this property is set to Empty, a user right-clicked the empty area.

The code below adds the Full Collapse and Full Expand commands to the empty area context menu.

C#

using DevExpress.Utils.Menu;
using DevExpress.Utils.Svg;
using DevExpress.XtraTreeList;
using DevExpress.XtraTreeList.Localization;

treeList1.PopupMenuShowing += OnPopupMenuShowing;

void OnPopupMenuShowing(object sender, PopupMenuShowingEventArgs e) {
    TreeList treeList = sender as TreeList;
    if(e.HitInfo.HitInfoType == HitInfoType.Empty) {
        string expandAllCaption = TreeListLocalizer.Active.GetLocalizedString(TreeListStringId.MenuNodeExpandAll);
        DXMenuItem expandAll = new DXMenuItem(expandAllCaption, (ss, ee) => treeList.ExpandAll());
        expandAll.ImageOptions.SvgImage = CommonSvgImages.Get(CommonSvgImages.Column.ExpandAll);
        e.Menu.Items.Add(expandAll);
        string collapseAllCaption = TreeListLocalizer.Active.GetLocalizedString(TreeListStringId.MenuNodeCollapseAll);
        DXMenuItem collapseAll = new DXMenuItem(collapseAllCaption, (ss, ee) => treeList.CollapseAll());
        collapseAll.ImageOptions.SvgImage = CommonSvgImages.Get(CommonSvgImages.Column.CollapseAll);
        e.Menu.Items.Add(collapseAll);
        e.Allow = true;
    }
}

VB.NET

Imports DevExpress.Utils.Menu
Imports DevExpress.Utils.Svg
Imports DevExpress.XtraTreeList
Imports DevExpress.XtraTreeList.Localization

AddHandler treeList1.PopupMenuShowing, AddressOf OnPopupMenuShowing

Private Sub OnPopupMenuShowing(ByVal sender As Object, ByVal e As PopupMenuShowingEventArgs)
    Dim treeList As TreeList = TryCast(sender, TreeList)
    If e.HitInfo.HitInfoType = HitInfoType.Empty Then
        Dim expandAllCaption As String = TreeListLocalizer.Active.GetLocalizedString(TreeListStringId.MenuNodeExpandAll)
        Dim expandAll As New DXMenuItem(expandAllCaption, Sub(ss, ee) treeList.ExpandAll())
        expandAll.ImageOptions.SvgImage = CommonSvgImages.Get(CommonSvgImages.Column.ExpandAll)
        e.Menu.Items.Add(expandAll)
        Dim collapseAllCaption As String = TreeListLocalizer.Active.GetLocalizedString(TreeListStringId.MenuNodeCollapseAll)
        Dim collapseAll As New DXMenuItem(collapseAllCaption, Sub(ss, ee) treeList.CollapseAll())
        collapseAll.ImageOptions.SvgImage = CommonSvgImages.Get(CommonSvgImages.Column.CollapseAll)
        e.Menu.Items.Add(collapseAll)
        e.Allow = True
    End If
End Sub