我调用模板的页面包含一个自定义控件，自定义控件里有 DropDownList1，表单提交后怎么也得不到DropDownList1的值？

自定义控件页面的代码  NewAddControl.ascx
if (!IsPostBack)
        {
            int nid = Convert.ToInt32(Request.QueryString["nid"]);
            string strsql = "select Cid,Ccaption from navFrist";
            NewsClass ns = new NewsClass();
            DataTable ds = ns.GetMessageList(strsql);
            DropDownList1.DataSource = ds;
            DropDownList1.DataTextField = "Ccaption";
            DropDownList1.DataValueField = "cid";
            DropDownList1.DataBind();
            DropDownList1.Items.Insert(0, new ListItem("请选择栏目", "0"));
}
自定义控件里还有一个按钮单击按钮得不到cDropDownList1的值
    protected void Button1_Click(object sender, EventArgs e)
    {
        NewsClass nad = new NewsClass();
        nad.content = DropDownList1.SelectedValue;    }
而且如果不加!IsPostBack  DropDownList1.SelectedValue的值始终为0 加上就没有任何值，我的页面是调用模板运行的
跟踪运行DropDownList1当提交以后就没有任何值了，不知道是在什么时候丢失的值？
帮我看看是什么问题谢谢！

解决方案 »

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你有没有关viewstate?
我试过是行的//WEB控件代码
  protected void Button1_Click(object sender, EventArgs e)
    {
        string a=this.DropDownList1.SelectedValue;
    }
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            SqlConnection conn = new SqlConnection("*******");
            SqlCommand cmd = new SqlCommand("select * from c_propertytype", conn);
            System.Data.DataTable dt = new System.Data.DataTable();
            using (SqlDataAdapter da = new SqlDataAdapter(cmd))
            {
                conn.Open();
                da.Fill(dt);
                conn.Close();
            }
            this.DropDownList1.DataTextField= "propertytypename";
            this.DropDownList1.DataValueField = "propertytypeid";
            this.DropDownList1.DataSource = dt;
            this.DropDownList1.DataBind();
            this.DropDownList1.Items.Insert(0, new ListItem("请选择栏目", "0"));         }
//页面中没有写任何代码.如果你的页面的viewstate关闭了的话是不行的.
我是用模板套的下面是我的页面帮忙看看
MasterPage.master
-------------------------------------------------------
<%@ Master Language="C#" AutoEventWireup="true" CodeFile="MasterPage.master.cs" Inherits="manage_master_MasterPage" %>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>无标题页 </title>
</head>
<body style="margin-top:0; margin-left:0;">
    <div>
        <table border="0" cellpadding="0" cellspacing="0" style="width: 100%; height: 100%">
            <tr>
                <td style="height: 214px" valign=top>
                    <div class="" id="rightChannel">
                        <form id="form1" runat="server">
                        <asp:contentplaceholder id="ContentPlaceHolder1" runat="server">
                        </asp:contentplaceholder>
                        </form>
                    </div>
                </td>
            </tr>
            <tr>
                <td colspan="2" style="height: 200px">
                </td>
            </tr>
        </table>
    </div>
</body>
</html> 调用页面admin_navmoid.aspx
<%@ Page Language="C#" MasterPageFile="~/manage/master/MasterPage.master" AutoEventWireup="true" CodeFile="admin_navmoid.aspx.cs" Inherits="manage_master_admin_navmoid" Title="Untitled Page" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
<ul>
    <li class="title sysColor_bg1 sysTitle" style="height:30px;" >栏目管理 </li> <li class="item" style="width:200px; float:left; text-align:left">
        <div>现栏目名称： </div>
        <div> <asp:ListBox ID="ListBox1" runat="server" Height="300px" Width="200px" AutoPostBack="true" OnSelectedIndexChanged="ListBox1_SelectedIndexChanged1"> </asp:ListBox> </div>
    </li>
    <li class="item" style="width:200px; float:left; text-align:left">
        <div>修改栏目名称： </div>
        <div class="sysColor_bg4 nav" style=" width:100%; height:300px; border:1px solid #959595;">
            <table width="388" border="0" cellpadding="0" cellspacing="0">
              
              <tr>
                <td height="25" valign="top" style="width: 118px; font-size:12px;" align="right">栏目名称: </td>
              <td valign="top" style="width: 259px"> <asp:TextBox ID="Ccaption" runat="server"> </asp:TextBox>   </td>
              </tr>
              <tr>
                <td height="25" valign="top" style="width: 118px;font-size:12px;" align="right">栏目配图: </td>
                <td valign="top" style="width: 259px">
                    <asp:FileUpload ID="FileUpload1" runat="server" />   </td>
              </tr>
              <tr>
                <td height="25" valign="top" style="width: 118px" align="right">   </td>
                <td valign="top" style="width: 259px">   <asp:Button ID="Button1" runat="server" Text="修改" /> </td>
              </tr>
              <tr>
                <td valign="top" style="width: 118px; height: 25px;font-size:12px;" align="right">录入时间: </td>
                <td valign="top" style="width: 259px; height: 25px;font-size:12px;"> </td>
              </tr>
              <tr>
                <td height="25" valign="top" style="width: 118px;font-size:12px;" align="right">现有栏目配图: </td>
                <td valign="top" style="width: 259px;font-size:12px;"> </td>
              </tr>
            </table>
        </div>
    </li>
</ul>
</asp:Content>
是viewstate的问题十分感谢