Hi

error occurs: Control 'Rpttran' referenced by the ControlToValidate property of 'R10M' cannot be validated.

I use repeater in my page below are codes:

<div id="Dsep131">
    <div class="dropdown">
        <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown"
            aria-haspopup="true" aria-expanded="false" style="width: 90px !important;height:30px;">نوع واگذاری
        </button>
        <div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
            <asp:Repeater ID="Rpttran" runat="server">
                <ItemTemplate>
                    <li><a target="_blank" class="dropdown-item" ID="btnsystem" runat="server" CommandArgument='<%# Eval("Transfer") %>'> <%# Eval("Transfer") %></a></li>
                </ItemTemplate>
            </asp:Repeater>
         </div>
      </div>
   </div>

and I want to use RequiredFieldValidator  for repeater so I use below code:

<asp:RequiredFieldValidator Display="Dynamic" ID="R10M" runat="server" ControlToValidate="Rpttran" InitialValue="0"></asp:RequiredFieldValidator>

how I can use validation for a repeater?

Best regards

Neda