TreeNode.Expand Method

Definition

Expands the tree node.

public:
 void Expand();
public void Expand ();
member this.Expand : unit -> unit
Public Sub Expand ()

Examples

The following code example toggles the selected node when a button is clicked. If the selected node is collapsed, it is expanded, if it is expanded by calling the Expand method, it is collapsed by calling the Collapse method. This example requires that you have a Form with a TreeView control that has at least one TreeNode with at least one child TreeNode.

void button1_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
{
   if ( treeView1->SelectedNode->IsExpanded )
   {
      treeView1->SelectedNode->Collapse();
      MessageBox::Show( String::Concat( treeView1->SelectedNode->Text, " tree node collapsed." ) );
   }
   else
   {
      treeView1->SelectedNode->Expand();
      MessageBox::Show( String::Concat( treeView1->SelectedNode->Text, " tree node expanded." ) );
   }
}
private void button1_Click(object sender, System.EventArgs e)
{
   if (treeView1.SelectedNode.IsExpanded)
   {
      treeView1.SelectedNode.Collapse();
      MessageBox.Show(treeView1.SelectedNode.Text + 
        " tree node collapsed.");
   }
   else
   {
      treeView1.SelectedNode.Expand();
      MessageBox.Show(treeView1.SelectedNode.Text + 
        " tree node expanded.");
   }
}
Private Sub button1_Click(sender As Object, _
  e As System.EventArgs) Handles button1.Click
   If treeView1.SelectedNode.IsExpanded Then
      treeView1.SelectedNode.Collapse()
      MessageBox.Show(treeView1.SelectedNode.Text & _ 
        " tree node collapsed.")
   Else
      treeView1.SelectedNode.Expand()
      MessageBox.Show(treeView1.SelectedNode.Text & _
        " tree node expanded.")
   End If
End Sub 

Remarks

The Expand method expands the current TreeNode down to the next level of nodes.

Note

The state of a TreeNode is persisted. For example, if the next level of child nodes was not collapsed previously, when the Expand method is called, the child nodes appear in their previously expanded state.

Applies to

See also