TreeViewNodeCancelEventArgs.Cancel Property
Gets or sets a value indicating whether the action that raised the event should be canceled.
Namespace: DevExpress.Web
Assembly: DevExpress.Web.v24.2.dll
NuGet Package: DevExpress.Web
#Declaration
#Property Value
Type | Description |
---|---|
Boolean |
|
#Remarks
The TreeViewNodeCancelEventArgs object is passed to the events that fire before specific actions. The Cancel property of this object enables you to cancel the action which is about to be performed. Set this property to true to cancel the action that raised the event. This can be used if you want to prohibit performing the corresponding action with respect to specific conditions.
#Example
The sample code below represents an ExpandedChanging event handler. The event handler prevents collapsing nodes if it has selected children in any generation.
<dx:ASPxTreeView ID="ASPxTreeView1" runat="server" DataSourceID="XmlDataSource1" AutoPostBack="True"
AllowSelectNode="True" OnExpandedChanging="ASPxTreeView1_ExpandedChanging" />
<asp:XmlDataSource ID="XmlDataSource1" runat="server" DataFile="~/App_Data/MenuTabbedMenu.xml"
XPath="/mainmenu/item"></asp:XmlDataSource>
protected void ASPxTreeView1_ExpandedChanging(object source, DevExpress.Web.ASPxTreeView.TreeViewNodeCancelEventArgs e) {
if ((e.Node.Expanded) && (ASPxTreeView1.SelectedNode != null)) {
TreeViewNode node = ASPxTreeView1.SelectedNode.Parent;
while (node != null) {
if (e.Node == node) {
e.Cancel = true;
break;
}
node = node.Parent;
}
}
}