网页对话框传值问题

1。父页面脚本

<SCRIPT>
     var win=window.showModalDialog("test.aspx");
     Form1.TextBox1.value = win;
</SCRIPT>

2。父页面按钮代码

StringBuilder str = new StringBuilder();
str.Append("<script language=javascript>win=window.showModalDialog(\"test.aspx\");</script>");

3。子页面按钮代码

string hhe = this.TextBox1.Text;
   string str = "<script language=javascript>\n";
   str += "window.returnValue=\"";
   str += hhe;
   str += "\";\nwindow.close();\n";
   str += "</script>";
   Page.RegisterClientScriptBlock("clientScript",str);