TreeView checkbox选中后取不到值

[robin18]

代码如下：
前台：
<asp:TreeView ID="treeMenu" runat="server" ExpandDepth="0" Font-Names="宋体" Font-Size="12px" ShowCheckBoxes="All" ForeColor="Black">
<LeafNodeStyle CssClass="treeRightCss table" />

CS:
if (node == null)
{
foreach (TreeNode treeNode in this.treeMenu.Nodes)
{
if (treeNode.Checked && treeNode.ChildNodes.Count == 0)
this.Items += treeNode.Text.Trim() + ",";
if (treeNode.ChildNodes.Count > 0)
SaveItemsTreeNode(treeNode);
}
}
else
{
foreach (TreeNode treeNode in node.ChildNodes)
{
if (treeNode.Checked & treeNode.ChildNodes.Count == 0)
this.Items += treeNode.Text.Trim() + ",";

if (treeNode.ChildNodes.Count > 0)
SaveItemsTreeNode(treeNode);
}
}

但是情况是 我checkbox选中了 在CS里面也取不到值，他的checked属性依然是false 这是为什么。。。。怎么解决啊

[wuhan_dotnet]

要确定你是不是重新绑定过一次TreeView