System.Web.UI.WebControls.TreeView.CollapseAll C# (CSharp) Method

		public void CollapseAll ()
		{
			foreach (TreeNode node in Nodes)
				node.CollapseAll ();
		}
		

        //protected override void RenderFieldForDisplay(System.Web.UI.HtmlTextWriter output)
        //{
        //    string[] valueArray;
        //    List<SPListItem> objNodeCollectionForDisplay = new List<SPListItem>();
        //    string objNodeTitle = string.Empty;
        //    string objLookupColumn = string.Empty;
        //    StringBuilder Query = new StringBuilder();
        //    SPList objTaskList;


        //    objLookupColumn = objTreeViewControlField.ParentLookup;


        //    if (this.ListItemFieldValue != null)
        //    {
        //        objTaskList = SPContext.Current.Web.Lists[objTreeViewControlField.ListName];
        //        if (objTaskList != null)
        //        {

        //            valueArray = this.ListItemFieldValue.ToString().Split(new string[] { ";#" }, StringSplitOptions.RemoveEmptyEntries);
        //            if (this.ControlMode == SPControlMode.Display)
        //            {
        //                objNodeCollectionForDisplay = CreateNodeCollectionForDisplay(valueArray);
        //            }
        //            List<SPListItem> results = (from SPListItem item in objNodeCollectionForDisplay
        //                                        where (new SPFieldLookupValue(Convert.ToString(item[objTreeViewControlField.ParentLookup])).LookupValue == null)
        //                                        orderby item.ID
        //                                        select item).ToList();

        //            foreach (SPListItem objLstItem in results)
        //            {
        //                CreateTree(objLstItem["Title"].ToString(), null, objNodeCollectionForDisplay, objLstItem[objTreeViewControlField.ValueColumn].ToString());
        //            }
        //            objTreeView.RenderControl(output);

        //        }
        //    }
        //}

        #endregion Overridden RenderFieldForDisplay Method for Display Mode


        #region CreateTree Method

        private void CreateTree(string RootNode, string[] valueArray, List <SPListItem> objNodeCollection, string DisplayValue)
        {
            TreeNode objTreeNode;

            objTreeView.ShowLines = true;

            objTreeNode = new TreeNode(DisplayValue, RootNode);
            objTreeView.Nodes.Add(objTreeNode);
            objTreeNode.SelectAction = TreeNodeSelectAction.None;
            /*******Check for parent node if no child exists Show Checkbox -- Start***************/
            if (this.ControlMode != SPControlMode.Display)
            {
                if (valueArray != null && this.ControlMode == SPControlMode.Edit && valueArray.Contains(objTreeNode.Value))
                {
                    objTreeNode.ShowCheckBox = true;
                    objTreeNode.Checked      = true;
                }
                else
                {
                    objTreeNode.ShowCheckBox = true;
                }
            }
            /*******Check for parent node if no child exists Show Checkbox -- End***************/
            TreeNodeCollection objTreenodeColn = GetChildNode(RootNode, valueArray, objNodeCollection);

            foreach (TreeNode childnode in objTreenodeColn)
            {
                objTreeNode.ChildNodes.Add(childnode);
                childnode.SelectAction = TreeNodeSelectAction.None;
                if (valueArray != null && this.ControlMode == SPControlMode.Edit && valueArray.Contains(objTreeNode.Value))
                {
                    objTreeNode.ShowCheckBox = true;
                    objTreeNode.Checked      = true;
                }
                else if (this.ControlMode == SPControlMode.Display)
                {
                    objTreeNode.ShowCheckBox = false;
                }
                else
                {
                    objTreeNode.ShowCheckBox = true;
                }
            }

            objExpandValue = objTreeViewControlField.ExpandCollapse.ToString();
            if (objExpandValue.Equals("True"))
            {
                objTreeView.ExpandAll();
            }
            else
            {
                objTreeView.CollapseAll();
            }
        }