TreeViewEventArgs::Action Property
.NET Framework (current version)
Gets the type of action that raised the event.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
Property Value
Type: System.Windows.Forms::TreeViewActionThe type of TreeViewAction that raised the event.
The following example illustrates a customized TreeView. By inheriting the TreeView class, this custom version has all the functionality of a normal TreeView. Changing various property values in the constructor provides a unique appearance. Because the ShowPlusMinus property is set to false, the customized control also overrides the OnAfterSelect method so nodes can be expanded and collapsed when they are clicked.
A control that is customized in this way can be used throughout an organization, making it easy to provide a consistent interface without requiring the control properties to be specified in each individual project.
public ref class CustomizedTreeView: public TreeView { public: CustomizedTreeView() { // Customize the TreeView control by setting various properties. BackColor = System::Drawing::Color::CadetBlue; FullRowSelect = true; HotTracking = true; Indent = 34; ShowPlusMinus = false; // The ShowLines property must be false for the FullRowSelect // property to work. ShowLines = false; } protected: virtual void OnAfterSelect( TreeViewEventArgs^ e ) override { // Confirm that the user initiated the selection. // This prevents the first node from expanding when it is // automatically selected during the initialization of // the TreeView control. if ( e->Action != TreeViewAction::Unknown ) { if ( e->Node->IsExpanded ) { e->Node->Collapse(); } else { e->Node->Expand(); } } // Remove the selection. This allows the same node to be // clicked twice in succession to toggle the expansion state. SelectedNode = nullptr; } };
.NET Framework
Available since 1.1
Available since 1.1
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