TreeList.PopupMenuShowing Event

Allows you to customize the default menus for column headers, row and footer summaries, nodes, and the empty area.

Namespace: DevExpress.XtraTreeList

Assembly: DevExpress.XtraTreeList.v20.1.dll

Declaration

[DXCategory("Behavior")]
public event PopupMenuShowingEventHandler PopupMenuShowing
<DXCategory("Behavior")>
Public Event PopupMenuShowing As PopupMenuShowingEventHandler

Event Data

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

Property Description
Allow Gets or sets if display of the menu is allowed.
HitInfo Provides access to information about the clicked visual element.
Menu Gets or sets the control's popup menu that will be shown.
MenuType Gets the type of the context menu that is about to be shown.
Point Gets the position where the menu is to be invoked.

Remarks

The Tree List shows a context menu when the user right-clicks within the following areas:

Examples

The following sample code handles the TreeList.PopupMenuShowing event for the following two purposes.

  • Disables the summary footer context menu for the "Department" column.
  • Removes the "Runtime columns customization" item of the column header context menu.
using DevExpress.XtraTreeList;

private void treeList1_PopupMenuShowing(object sender, PopupMenuShowingEventArgs e) {
    TreeList treeList = sender as TreeList;
    TreeListHitInfo hitInfo = treeList.CalcHitInfo(e.Point);

    // prohibiting summary footer menu for the "Department" column
    if (hitInfo.HitInfoType == HitInfoType.SummaryFooter &&
      hitInfo.Column.Caption == "Department")
        e.Allow = false;

    // removing the "Runtime columns customization" item of the column header menu
    if (hitInfo.HitInfoType == HitInfoType.Column) {
        string caption = TreeListLocalizer.Active.GetLocalizedString(GetMenuColumnCustomizationStringId(treeList));
        e.Menu.Items.Remove(e.Menu.Items.FirstOrDefault(x => x.Caption == caption));
    }
}

private TreeListStringId GetMenuColumnCustomizationStringId(TreeList treeList) {
    if (treeList.OptionsView.ShowBandsMode == DefaultBoolean.True || (treeList.OptionsView.ShowBandsMode == DefaultBoolean.Default && treeList.Bands.Count > 0))
        return TreeListStringId.MenuColumnBandCustomization;
    return TreeListStringId.MenuColumnColumnCustomization;
}

The following example demonstrates how to add a custom item to a standard context menu and handle the click event for this item. The TreeList.PopupMenuShowing event is handled to add the Clear All item to the summary footer menu. Clicking this item cancels the summary calculations for all Tree List columns.

ContextMenus - CustomItemClick

using DevExpress.Utils.Menu;
using DevExpress.XtraTreeList;
using DevExpress.XtraTreeList.Columns;
//...
private void treeList1_PopupMenuShowing(object sender, DevExpress.XtraTreeList.PopupMenuShowingEventArgs e) {
    TreeList tL = sender as TreeList;
    TreeListHitInfo hitInfo = tL.CalcHitInfo(e.Point);
    if (hitInfo.HitInfoType == HitInfoType.SummaryFooter) {
        DXMenuItem menuItem = new DXMenuItem("Clear All", new EventHandler(this.clearAllMenuItemClick));
        menuItem.Tag = hitInfo.Column;
        e.Menu.Items.Add(menuItem);
    }
}

private void clearAllMenuItemClick(object sender, EventArgs e) {
    TreeListColumn clickedColumn = (sender as DXMenuItem).Tag as TreeListColumn;
    if (clickedColumn == null) return;
    TreeList tl = clickedColumn.TreeList;
    foreach (TreeListColumn column in tl.Columns)
        column.SummaryFooter = SummaryItemType.None;
}

The example below shows how to display a custom context menu with a click on a node indicator. The menu contains the Delete Node command.

The TreeList.PopupMenuShowing event fires when the default menu is about to be shown. The TreeList.CalcHitInfo method in the event handler returns internal information about the clicked visual element. If a node indicator is clicked, the Delete Node command is added to the menu. The DXMenuItem.Click event handler removes the node.

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

private void treeList1_PopupMenuShowing(object sender, DevExpress.XtraTreeList.PopupMenuShowingEventArgs e) {
    // Check if a node's indicator cell is clicked.
    TreeListHitInfo hitInfo = (sender as TreeList).CalcHitInfo(e.Point);
    TreeListNode node = null;
    if (hitInfo.HitInfoType == HitInfoType.RowIndicator) {
        node = hitInfo.Node;
    }
    if (node == null) return;
    // Create the Delete Node command.
    DXMenuItem menuItem = new DXMenuItem("Delete Node", new EventHandler(deleteNodeMenuItemClick));
    menuItem.Tag = node;
    e.Menu.Items.Add(menuItem);
}

private void deleteNodeMenuItemClick(object sender, EventArgs e) {
    DXMenuItem item = sender as DXMenuItem;
    if (item == null) return;
    TreeListNode node = item.Tag as TreeListNode;
    if (node == null) return;
    node.TreeList.DeleteNode(node);
}

The PopupMenuShowing event is raised before a context menu is shown and allows you to customize it. The HitInfo event argument is set to Empty when a user right-clicked the empty area.

The code below shows how to add the Full Collapse and Full Expand 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;
    }
}
See Also