How to FindControls in repeater control?

asp.net, c#, controls, repeater

Solution

You can toggle the enabled property of the button control using declarative syntax and display and format the `Event_Start_Date` using the Eval methods format parameter. This way there is no need for the CheckEnability method.

<asp:Repeater>
    <table>
         <tr>
            <td align="right" style=" font-weight:bold">Start Date : </td>
            <td><%# Eval("Event_Start_Date", "{0:yyyy-MM-dd}")%></td>
        </tr>
         <asp:Button ID="ParticipateBtn" Enabled='<%# Convert.ToDateTime(Eval("Event_Start_Date") ) < DateTime.Now %>' CommandName="Participate" CommandArgument='<%# Eval("Event_Id") + "|" + Eval("Event_Name") + "|" + Eval("Volume") + "|" + Eval("Tournament_Id") %>' runat="server" Text="Participate" />&nbsp;&nbsp;
    </ItemTemplate>
    <FooterTemplate></FooterTemplate>
    <SeparatorTemplate><hr style="color:Silver; height:1px;" /></SeparatorTemplate>
</asp:Repeater>

Problem

I want to enable or disable 'ParticipateBtn' depending on EventStartDate. I am getting this error:Object reference not set to an instance of an object. Start Date : <%# CheckEnability((DateTime)Eval("Event_Start_Date")) %> ``` <asp:Button runat="server" ID="ParticipateBtn" CommandName="Participate" CommandArgument='<%# Eval("Event_Id") + "|" + Eval("Event_Name") + "|" + Eval("Volume") + "|" + Eval("Tournament_Id") %>' Text="Participate" />&nbsp;&nbsp; </ItemTemplate> <FooterTemplate></FooterTemplate> <SeparatorTemplate> <hr style="color:Silver; height:1px;" /> </SeparatorTemplate> </asp:Repeater> ``` The code behind... ``` //Code behind protected string CheckEnability(DateTime eventstartdate) { if (eventstartdate.Date < DateTime.Now.Date) { Button btn = (Button)Repeater1.FindControl("ParticipateBtn"); btn.Enabled = false; } return eventstartdate.ToString("yyyy-MM-dd"); } ```

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