C# 如何持久化用户控件值？

我想保留用户控件值

如果我再添加一行，前面的控件值就不存在了

我浏览了一些网站，但我不能清楚地理解

代码：

这里我添加了用户控件

   protected void addnewtext_Click(object sender, EventArgs e)
    {
        int i = controlCount++;

        for (int j = 0; j <= i; j++)
        {
            AddVisaControl ac = (AddVisaControl)Page.LoadControl("AddVisaControl.ascx");
            Label lb = new Label();
            string z = Convert.ToString(j + 1);
            lb.Text = "Visa " + z;
            rpt1.Controls.Add(lb);
            lb.Attributes.Add("class", "style8");
            rpt1.Controls.Add(ac);
            rpt1.Controls.Add(new LiteralControl("<BR>"))    
        }  
    }

protectedvoid addnewtext\u单击（对象发送方，事件参数e）
{
int i=控制计数++；
对于（int j=0；j，必须在每次回发时添加动态控件，以便ViewState可以保持其值。有关详细信息，请阅读ASP.NET页面生命周期

   protected void addnewtext_Click(object sender, EventArgs e)
    {
        int i = controlCount++;

        for (int j = 0; j <= i; j++)
        {
            AddVisaControl ac = (AddVisaControl)Page.LoadControl("AddVisaControl.ascx");
            Label lb = new Label();
            string z = Convert.ToString(j + 1);
            lb.Text = "Visa " + z;
            rpt1.Controls.Add(lb);
            lb.Attributes.Add("class", "style8");
            rpt1.Controls.Add(ac);
            rpt1.Controls.Add(new LiteralControl("<BR>"))    
        }  
    }

 <%@ Control Language="C#" AutoEventWireup="true" CodeBehind="AddVisaControl.ascx.cs" EnableViewState="false" Inherits="Pyramid.AddVisaControl" %>
<div id="divreg" runat="server">
<table id="tbl" runat="server">
    <tr>
    <td>
        <asp:Label ID="lbl2" runat="server"></asp:Label>
    </td>
</tr>
<tr>
<td> Visa Number:</td>
<td><asp:TextBox ID="txtUser" Width="160px" runat="server"/></td>
<td> Country Name:</td>
<td><asp:DropDownList ID="dropCountry" Width="165px" runat="server"></asp:DropDownList></td>
</tr>
<tr>
<td> Type of Visa:</td>
<td><asp:DropDownList ID="dropVisa" Width="165px" runat="server"></asp:DropDownList></td>
<td> Type of Entry:</td>
<td><asp:DropDownList ID="dropEntry" Width="165px" runat="server"></asp:DropDownList></td>
</tr>
<tr>
<td> Expiry Date</td>
<td>

</td>
</tr>
</table>
</div>