主页面的代码:
  protected void Page_Load(object sender, EventArgs e)
    {



 this.TextBox1.Attributes["onClick"] = "UseOpenner()";
}



//主页面的源中
<SCRIPT LANGUAGE="JavaScript">
<!--
function UserOpenner()
{
 var  returnValue = window.showModalDialog("ShowTree.htm","A","dialogWidth=306px;dialogHeight=345px");
 if (returnValue != "点击")
 document.all.TextBox1.value = returnValue ;
 
}
//-->

</SCRIPT>


//  ShowTree.htm

!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>点击部门名称</title>
</head>
<body>

<iframe name ="treeframe" marginheight=0 marginwidth =0  height ='300' scrolling = auto  frameborder=0   width='300' src ='EM_Showwindow.aspx' ></iframe>
</body>
</html>





//'EM_Showwindow.aspx' 页面中

 protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)
    {
        string cc = this.TreeView1.SelectedNode.Value;
        this.RegisterStartupScript("ST", "<script language='javascript'>\nparent.window.returnValue = '" + cc + "';\nparent.window.close();\n</script>");
    }


 protected void RadioButtonList1_DataBound(object sender, EventArgs e)
    {
        //上级部门名称
        for (int i = 0; i < this.RadioButtonList1.Items.Count; i++)
        {
            this.RadioButtonList1.Items[i].Attributes.Add("onclick", "Show()");
        }
    }



//'EM_Showwindow.aspx' 页面.源中

!--  
    <SCRIPT LANGUAGE="JavaScript">
<!--
function Show()
{
var rdo = document.all.RadioButtonList1;
 for (i=0; i<rdo.length; i++)
    {
        if (rdo[i].checked)
        {
            selectedIndex = i;
            window.returnValue =  rdo[i].value;
     window.close(); 
            break;
        }
    }

}</SCRIPT>
//-->