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TreeNode.Collapse Method

Collapses the tree node.

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

public void Collapse()

The Collapse method collapses the current TreeNode and its child nodes. If you want to collapse only the current TreeNode, use the TreeNode.Collapse(Boolean) overload, passing true to ignore its child nodes.


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.

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.

private void button1_Click(object sender, System.EventArgs e)
   if (treeView1.SelectedNode.IsExpanded)
      MessageBox.Show(treeView1.SelectedNode.Text + 
        " tree node collapsed.");
      MessageBox.Show(treeView1.SelectedNode.Text + 
        " tree node expanded.");

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.