TreeList.PopupMenuShowing Event

Allows you to customize the default menus for column headers, summary footers and nodes.

Namespace: DevExpress.XtraTreeList

Assembly: DevExpress.XtraTreeList.v18.2.dll

Declaration

C#

[DXCategory("Behavior")]
public event PopupMenuShowingEventHandler PopupMenuShowing

VB.NET

<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.
Menu	Gets or sets the control’s popup menu that will be shown.
Point	Gets the position where the menu is to be invoked.

Remarks

The TreeList control supports context menus for column headers, summary footers and nodes. By default, the menus for column headers and summary footers are not empty, while the menu for nodes is empty.

Use the PopupMenuShowing event to customize these menus by adding/removing menu items. It’s also possible to disable the menus via the event’s Allow parameter.

To get the type of the menu, read the e.Menu.MenuType parameter, which is of the TreeListMenuType type.

The TreeList.OptionsMenu property provides options controlling the availability of the context menus for column headers and summary footers.

Example

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.

C#

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;
}

VB.NET

Imports DevExpress.Utils.Menu
Imports DevExpress.XtraTreeList
Imports DevExpress.XtraTreeList.Columns
'...
Private Sub TreeList1_PopupMenuShowing(sender As Object, e As DevExpress.XtraTreeList.PopupMenuShowingEventArgs) Handles TreeList1.PopupMenuShowing
    Dim tL As TreeList = sender
    Dim HitInfo As TreeListHitInfo = tL.CalcHitInfo(e.Point)
    If HitInfo.HitInfoType = HitInfoType.SummaryFooter Then
        Dim menuItem As New DXMenuItem("Clear All", AddressOf Me.clearAllMenuItemClick)
        menuItem.Tag = HitInfo.Column
        e.Menu.Items.Add(menuItem)
    End If
End Sub

Private Sub clearAllMenuItemClick(ByVal sender As Object, ByVal e As EventArgs)
    Dim clickedColumn As TreeListColumn = CType(CType(sender, DXMenuItem).Tag, TreeListColumn)
    If clickedColumn Is Nothing Then Return
    Dim treeList1 As TreeList = clickedColumn.TreeList
    For Each Column In treeList1.Columns
        Column.SummaryFooter = SummaryItemType.None
    Next
End Sub

Example

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.

C#

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;
}

VB.NET

Imports DevExpress.XtraTreeList

Private Sub treeList1_PopupMenuShowing(ByVal sender As Object, ByVal e As PopupMenuShowingEventArgs)
    Dim treeList As TreeList = TryCast(sender, TreeList)
    Dim hitInfo As TreeListHitInfo = treeList.CalcHitInfo(e.Point)

    ' prohibiting summary footer menu for the "Department" column
    If hitInfo.HitInfoType = HitInfoType.SummaryFooter AndAlso hitInfo.Column.Caption = "Department" Then
        e.Allow = False
    End If

    ' removing the "Runtime columns customization" item of the column header menu
    If hitInfo.HitInfoType = HitInfoType.Column Then
        Dim caption As String = TreeListLocalizer.Active.GetLocalizedString(GetMenuColumnCustomizationStringId(treeList))
        e.Menu.Items.Remove(e.Menu.Items.FirstOrDefault(Function(x) x.Caption = caption))
    End If
End Sub

Private Function GetMenuColumnCustomizationStringId(ByVal treeList As TreeList) As TreeListStringId
    If treeList.OptionsView.ShowBandsMode = DefaultBoolean.True OrElse (treeList.OptionsView.ShowBandsMode = DefaultBoolean.Default AndAlso treeList.Bands.Count > 0) Then
        Return TreeListStringId.MenuColumnBandCustomization
    End If
    Return TreeListStringId.MenuColumnColumnCustomization
End Function

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the PopupMenuShowing event.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

VB.NET

how-to-implement-the-cells-multi-selection-feature-in-treelist-e2795/VB/WindowsApplication1/Helper/BlockSelector.vb#L36

AddHandler fList.KeyDown, AddressOf fList_KeyDown
AddHandler fList.PopupMenuShowing, AddressOf fList_PopupMenuShowing
AddHandler fList.EditorKeyDown, AddressOf fList_EditorKeyDown