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TreeView::DrawMode Property

 

Gets or sets the mode in which the control is drawn.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

public:
property TreeViewDrawMode DrawMode {
	TreeViewDrawMode get();
	void set(TreeViewDrawMode value);
}

Property Value

Type: System.Windows.Forms::TreeViewDrawMode

One of the TreeViewDrawMode values. The default is TreeViewDrawMode::Normal.

Exception Condition
InvalidEnumArgumentException

The property value is not a valid TreeViewDrawMode value.

The nodes of a TreeView are typically drawn by the operating system. The DrawMode property lets you customize the appearance of the nodes. To do this, set DrawMode to TreeViewDrawMode::OwnerDrawAll or TreeViewDrawMode::OwnerDrawText and provide a handler for the DrawNode event. This is called owner drawing.

The following code example demonstrates how to customize a TreeView control using owner drawing. The TreeView control in the example displays optional node tags alongside the standard node labels. Node tags are specified by using the TreeNode::Tag property. The TreeView control also uses custom colors, which include a custom highlight color.

You can customize most of the TreeView colors by setting color properties, but the selection highlight color is not available as a property. Additionally, the default selection highlight rectangle extends only around a node label. Owner drawing must be used to draw the node tags and to draw a customized highlight rectangle large enough to include a node tag.

For the complete example, see the DrawNode reference topic.

TreeViewOwnerDraw()
{
   tagFont = gcnew System::Drawing::Font( "Helvetica",8,FontStyle::Bold );

   // Create and initialize the TreeView control.
   myTreeView = gcnew TreeView;
   myTreeView->Dock = DockStyle::Fill;
   myTreeView->BackColor = Color::Tan;
   myTreeView->CheckBoxes = true;

   // Add nodes to the TreeView control.
   TreeNode^ node;
   for ( int x = 1; x < 4; ++x )
   {
      // Add a root node to the TreeView control.
      node = myTreeView->Nodes->Add( String::Format( "Task {0}", x ) );
      for ( int y = 1; y < 4; ++y )
      {
         // Add a child node to the root node.
         node->Nodes->Add( String::Format( "Subtask {0}", y ) );
      }
   }
   myTreeView->ExpandAll();

   // Add tags containing alert messages to a few nodes 
   // and set the node background color to highlight them.
   myTreeView->Nodes[ 1 ]->Nodes[ 0 ]->Tag = "urgent!";
   myTreeView->Nodes[ 1 ]->Nodes[ 0 ]->BackColor = Color::Yellow;
   myTreeView->SelectedNode = myTreeView->Nodes[ 1 ]->Nodes[ 0 ];
   myTreeView->Nodes[ 2 ]->Nodes[ 1 ]->Tag = "urgent!";
   myTreeView->Nodes[ 2 ]->Nodes[ 1 ]->BackColor = Color::Yellow;

   // Configure the TreeView control for owner-draw and add
   // a handler for the DrawNode event.
   myTreeView->DrawMode = TreeViewDrawMode::OwnerDrawText;
   myTreeView->DrawNode += gcnew DrawTreeNodeEventHandler( this, &TreeViewOwnerDraw::myTreeView_DrawNode );

   // Add a handler for the MouseDown event so that a node can be 
   // selected by clicking the tag text as well as the node text.
   myTreeView->MouseDown += gcnew MouseEventHandler( this, &TreeViewOwnerDraw::myTreeView_MouseDown );

   // Initialize the form and add the TreeView control to it.
   this->ClientSize = System::Drawing::Size( 292, 273 );
   this->Controls->Add( myTreeView );
}

.NET Framework
Available since 2.0
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