TreeView.ExpandAll Method
Definition
Important
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Expands all the tree nodes.
public:
void ExpandAll();public void ExpandAll ();member this.ExpandAll : unit -> unitPublic Sub ExpandAll ()Examples
The following code example expands all the tree nodes in a TreeView control when a CheckBox is checked, and collapses the FirstNode when the CheckBox is cleared. This example requires that you have a Form with a CheckBox, and a TreeView control with a TreeNodeCollection that has several TreeNode objects (preferably with three or more levels).
void myCheckBox_CheckedChanged( Object^ /*sender*/, System::EventArgs^ /*e*/ )
{
// If the check box is checked, expand all the tree nodes.
if ( myCheckBox->Checked == true )
{
myTreeView->ExpandAll();
}
else
{
// If the check box is not checked, collapse the first tree node.
myTreeView->Nodes[ 0 ]->FirstNode->Collapse();
MessageBox::Show( "The first node of CustomerList root node is collapsed" );
}
}
private void myCheckBox_CheckedChanged(object sender, System.EventArgs e)
{
// If the check box is checked, expand all the tree nodes.
if (myCheckBox.Checked == true)
{
myTreeView.ExpandAll();
}
else
{
// If the check box is not checked, collapse the first tree node.
myTreeView.Nodes[0].FirstNode.Collapse();
MessageBox.Show("The first node of CustomerList root node is collapsed");
}
}
Private Sub myCheckBox_CheckedChanged(ByVal sender As Object, _
ByVal e As System.EventArgs) Handles myCheckBox.CheckedChanged
' If the check box is checked, expand all the tree nodes.
If myCheckBox.Checked = True Then
myTreeView.ExpandAll()
Else
' If the check box is not checked, collapse the first tree node.
myTreeView.Nodes(0).FirstNode.Collapse()
MessageBox.Show("The first node of CustomerList root node is collapsed")
End If
End Sub
Remarks
The ExpandAll method expands all the TreeNode objects, which includes all the child tree nodes, that are in the TreeView control.
Note
The state of a TreeNode persists. For example, suppose that you call the ExpandAll method, and then the individual root tree nodes are collapsed. The child tree nodes have not been collapsed, and will appear in their previously-expanded state when the root tree nodes are expanded again. Calling the CollapseAll method ensures that all the tree nodes appear in the collapsed state.
