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Empty-Area Context Menu
- 2 minutes to read
The Tree List shows a context menu when the user right-clicks within the following areas:
- Column Header — the control shows the Column Header Context Menu if the EnableColumnMenu option is enabled. The menu contains commands related to columns: sorting, filtering, etc.
- Node — the control shows the Node Context Menu if the EnableNodeMenu option is enabled. The menu contains commands related to nodes: expand, collapse, create a new node, etc.
- Group Footer, Summary Footer — the control shows the Footer Context Menu if the EnableFooterMenu option is enabled. The menu contains commands related to summaries: sum, min, average, etc.
- Empty Area — the menu invoked with a right-click below the tree list's nodes. The default empty-area context menu does not contain any commands. Use the PopupMenuShowing event to populate the menu.
Populate the Menu
The PopupMenuShowing event raises before a context menu is shown and allows you to customize it. Use the HitInfo event argument to get the clicked visual element: column header, band header, node, footer, empty area, etc.
The code below shows how to add the Collapse All and Expand All commands to the empty-area context menu.
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;
}
}
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