using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI.WebControls;
/// <summary>
/// Heros TreeView保存和恢復結點展開狀態的輔助類
/// </summary>
public class TreeNodesExpandStateManager : IDisposable
{
TreeView _tree;
List<TreeNode> nodes = new List<TreeNode>();
public static string SessionKey = "TreeNodesExpandState";
public TreeNodesExpandStateManager(TreeView tree)
{
_tree = tree;
}
/// <summary>
/// 保存當前樹的展開狀態
/// </summary>
public void SaveExpandState()
{
foreach (TreeNode node in this._tree.Nodes)
{
SearchExpandedNode(node);
}
}
private void SearchExpandedNode(TreeNode node)
{
if (node == null)
return;
else
{
if (node.Expanded ?? false)
{
nodes.Add(node);
foreach (TreeNode item in node.ChildNodes)
{
SearchExpandedNode(item);
}
}
}
}
/// <summary>
/// 恢復當前樹的展開狀態
/// </summary>
public void RestoreExpandState()
{
foreach (TreeNode node in this._tree.Nodes)
{
SetNodeExpandState(node);
}
}
/// <summary>
/// 用於跨頁操作時,恢復到指定樹
/// </summary>
/// <param name="tree"></param>
public void RestoreExpandStateToTree(TreeView tree)
{
foreach (TreeNode node in tree.Nodes)
{
SetNodeExpandState(node);
}
}
private void SetNodeExpandState(TreeNode node)
{
if (node == null)
return;
else
{
if (this.nodes.Contains(node, new EqualEntity()))
{
node.Expand();
foreach (TreeNode item in node.ChildNodes)
{
SetNodeExpandState(item);
}
}
}
}
/// <summary>
/// 將指定樹展開狀態存入會話,一般在樹的展開和合閉事件中調用
/// </summary>
/// <param name="tree">目標樹</param>
public static void SaveExpandStateInSession(TreeView tree, string sessionKey)
{
if (tree == null)
return;
TreeNodesExpandStateManager manager = new TreeNodesExpandStateManager(tree);
manager.SaveExpandState();
HttpContext.Current.Session[sessionKey] = manager;
}
/// <summary>
/// 將指定樹展開狀態存入默認會話,一般在樹的展開和合閉事件中調用
/// </summary>
/// <param name="tree">目標樹</param>
public static void SaveExpandStateInSession(TreeView tree)
{
SaveExpandStateInSession(tree, SessionKey);
}
/// <summary>
/// 將Session中的結點展開狀態恢復到指定樹,在樹結點添加結束後調用
/// </summary>
/// <param name="tree">目標樹</param>
public static void RestoreExpandStateToTreeFromSession(TreeView tree, string sessionKey)
{
if (HttpContext.Current.Session[sessionKey] == null || tree == null)
return;
TreeNodesExpandStateManager manager = HttpContext.Current.Session[sessionKey] as TreeNodesExpandStateManager;
manager.RestoreExpandStateToTree(tree);
}
/// <summary>
/// 將默認Session中的結點展開狀態恢復到指定樹,在樹結點添加結束後調用
/// </summary>
/// <param name="tree">目標樹</param>
public static void RestoreExpandStateToTreeFromSession(TreeView tree)
{
RestoreExpandStateToTreeFromSession(tree, SessionKey);
}
#region IDisposable 成員
public void Dispose()
{
this.nodes.Clear();
this.nodes = null;
this._tree.Dispose();
}
#endregion
~TreeNodesExpandStateManager()
{
this.Dispose();
}
public class EqualEntity : IEqualityComparer<TreeNode>
{
#region IEqualityComparer<TreeNode> 成員
public bool Equals(TreeNode x, TreeNode y)
{
if (x == null || y == null)
return false;
return x.Value.Equals(y.Value);
}
public int GetHashCode(TreeNode obj)
{
return obj.GetHashCode();
}
#endregion
}
}