Get the value of HiddenField inside asp.net repeater

Question

when I try to use a hidden field inside repeater inside repeater

<repeater>
   <repeater>
     <hiddenfield>

I tried this code to enter to the value

if (shiftrepeater.Items.Count > 0)
{
    for(int shiftcount = 0 ; shiftcount<shiftrepeater.Items.Count ; shiftcount++)
    {
        Repeater temp = (Repeater)shiftrepeater.Items[shiftcount].FindControl("saturdayrepeater");

        for (int count = 0; count < temp.Items.Count; count++)
        {
            DropDownList ds = (DropDownList)temp.FindControl("userdropdown");
            HiddenField hf = (HiddenField)temp.FindControl("hiddenid");
            SarcShiftUser user = new SarcShiftUser();
            user.id = int.Parse(hf.Value);
            user.workzone_id=1;
            user.xdate = saturday.Text;
            user.table_id = id;
            user.shift_id = shiftcount+1;

            user.user_id  = int.Parse(ds.SelectedValue);
            user.level_id= 1;
            user.team_id=1;


        }
    }
}

the asp.net code :

<asp:Repeater ID="saturdayrepeater" runat="server" DataSourceID="saturdayrepeaterds">
    <HeaderTemplate>
        <table width="100%" cellpadding="0" cellspacing="0">
    </HeaderTemplate>
    <ItemTemplate>
        <tr>
        <td>
            <asp:HiddenField ID="hiddenid" runat="server" Value='<%#Eval("id") %>'  />
            <asp:DropDownList ID="userdropdown" CssClass="select" runat="server" DataSourceID="userdropdownds" DataTextField="name" DataValueField="id" AppendDataBoundItems="true">
                <asp:ListItem Text="" Value="" Selected="True"></asp:ListItem>
             </asp:DropDownList>
        </td></tr>
    </ItemTemplate>
    <FooterTemplate>
        </table>
    </FooterTemplate>
</asp:Repeater>

every thing is ok ... but I got this error :

Object reference not set to an instance of an object.

at this line :

user.id = int.Parse(hf.Value);

Why do I get the error?

Answer 1

Looks like hf is null because you're trying to find the HiddenField using temp.FindControl instead of temp.Items[count].FindControl.

Change the following

DropDownList ds = (DropDownList)temp.FindControl("userdropdown");
HiddenField hf = (HiddenField)temp.FindControl("hiddenid");

to this

DropDownList ds = (DropDownList)temp.Items[count].FindControl("userdropdown");
HiddenField hf = (HiddenField)temp.Items[count].FindControl("hiddenid");

UPDATE

This line will throw an error if ds.SelectedValue is an empty string or contains non numeric characters

user.user_id  = int.Parse(ds.SelectedValue);

You need to change it to this

int userID = 0;
if (int.TryParse(ds.SelectedValue, out userID))
{
    user.user_id  = userID;
}
else
{
    // do something when ds.SelectedValue is non numeric
}

Answer 2

Try This

foreach (RepeaterItem items in temp.Items)
        {
            DropDownList ds = (DropDownList)items.FindControl("userdropdown");
            HiddenField hf = (HiddenField)items.FindControl("hiddenid");

          //your code
        }