repeater嵌套，如何找到子repeater单击的控件

问题遇到的现象和发生背景

我想知道如何先找到父repeater在找到子repeater的控件，按照我这样写执行时会报错
我做的是二级评论功能

用代码块功能插入代码，请勿粘贴截图

这是aspx代码

<asp:Repeater ID="Repeater1" runat="server" OnItemCommand="Repeater1_ItemCommand" >
                <ItemTemplate>
                     <li>
                         
                         
                 <h4><%#Eval("UserName") %>h4>
                 <small><%#Eval("Time").ToString() %>small>
                         
                 <div>
                     <%#Eval("Content") %>
                 div>
                         <asp:LinkButton ID="LinkButton1" runat="server" Text=<%#Eval("UserId") %> Visible="False" CommandArgument=<%#Eval("Id") %> CommandName="Delete">LinkButtonasp:LinkButton>
                         <asp:Label ID="Label1" runat="server" Text=<%#Eval("Id") %> Visible="false" >asp:Label>
                         <asp:LinkButton ID="LinkButton2" runat="server" Text="查看回复" CommandName="SRComment">查看回复asp:LinkButton>
                         <asp:LinkButton ID="LinkButton3" runat="server" Text="回复" CommandName="RComment">回复asp:LinkButton>
                          <asp:TextBox ID="RTextBox" runat="server" Width="80%" Height="50px" Visible="false">asp:TextBox>

                          <asp:Button ID="RButton" runat="server" Text="提交" CommandArgument=<%#Eval("Id") %> CommandName="RButton" Visible="false"/>


<asp:Repeater ID="Repeater2" runat="server" Visible="false" OnItemCommand="Repeater2_ItemCommand">
                            <ItemTemplate>
                                <li>
                                     <h4>       <%#Eval("SendName") %>   回复   <%#Eval("ReceiveName") %>  回复内容：<%#Eval("RContent").ToString().Length > 6 ? Eval("RContent").ToString().Substring(0, 6):Eval("RContent")%>... h4>
                                    <small><%#Eval("Time").ToString() %>small>
                                     <div>
                                                <%#Eval("Content") %>
                                     div>        
                                    <asp:LinkButton ID="DLin" runat="server" Text=<%#Eval("SendId") %>  Visible="False" CommandArgument=<%#Eval("Id") %> CommandName="Delete">LinkButtonasp:LinkButton>
                                    <asp:LinkButton ID="LinkButton3" runat="server" Text="回复" CommandName="RComment">回复asp:LinkButton>
                          <asp:TextBox ID="RTextBox" runat="server" Width="80%" Height="50px" Visible="false">asp:TextBox>
                          <asp:Button ID="RButton" runat="server" Text="提交" CommandArgument=<%#Eval("Comment1Id") %> CommandName="RButton" Visible="false"/>
                                li>
                            ItemTemplate>
                         asp:Repeater>
                         
            li>
                    
                ItemTemplate>
           
            asp:Repeater>

这是cs代码里子repeater2的itemcommand方法

 protected void Repeater2_ItemCommand(object source, RepeaterCommandEventArgs e)
    {
       
        if (e.CommandName == "Delete")
        {
            productSrv.DeleteCom2(Convert.ToInt32(e.CommandArgument));
            Bind2();
        }
        if (e.CommandName == "RComment")
        {

            Repeater rp = new Repeater();
            rp = (Repeater)Repeater1.Items[e.Item.ItemIndex].FindControl("Repeater2");

            TextBox rt = new TextBox();
                Button rbt = new Button();
                rt = (TextBox)rp.Items[e.Item.ItemIndex].FindControl("RTextbox");
                rbt = (Button)rp.Items[e.Item.ItemIndex].FindControl("RButton");

                if (rt.Visible == false && rbt.Visible == false)
                {
                    rbt.Visible = true; rt.Visible = true;
                }
                else
                {
                    rbt.Visible = false; rt.Visible = false;
                }
            
            
        }
        if (e.CommandName == "RButton")
        {
            Repeater rp = new Repeater();
            rp = (Repeater)Repeater1.Items[e.Item.ItemIndex].FindControl("Repeater2");

            TextBox rt = new TextBox();
                rt = (TextBox)rp.Items[e.Item.ItemIndex].FindControl("RTextbox");
                productSrv.AddComment22(Convert.ToInt32(e.CommandArgument), Convert.ToInt32(Session["CustomerId"]), Session["CustomerName"].ToString(), rt.Text);

                Bind2();
            }
        }