CheckBox Controls in Repeater not maintaining state

Question

Bit confused about this. I was under the impression that if you added server controls to the ItemTemplate of a repeater then the ID's assigned to those controls would persist across postbacks and the state would be maintained. But it doesn't seem to be happening. Here's my ItemTemplate:

<asp:HiddenField ID="hidPending" runat="server" value="<%# DataBinder.Eval(Container.DataItem, "Id")%>" />
<td class="leftpadd"><uc:restrictedtext ID="uclblCategory" runat="server" Width="125" /></td>
<td style="border-left:1px solid #528ABD;" class="leftpadd"><%# DataBinder.Eval(Container.DataItem, "SelectedOptions")%></td>
<td style="border-left:1px solid #528ABD;" class="leftpadd"><%# DataBinder.Eval(Container.DataItem, "Price.IncludingTax", "{0:C}")%></td>
<td style="border-left:1px solid #528ABD;" class="leftpadd"><%# DataBinder.Eval(Container.DataItem, "ExtrasCost", "{0:C}")%></td>
<td style="border-left:1px solid #528ABD;" class="leftpadd"><%# DataBinder.Eval(Container.DataItem, "Quantity", "{0:000}")%></td>
<td style="border-left:1px solid #528ABD;" class="leftpadd"><asp:CheckBox ID="chkPendingItems" runat="server" /></td>

Which populates fine. What I'm looking to happen is for the user to be able to select certain items from the repeater using the checkbox and "process" them (i.e. perform some data operations on those items) on clicking a button which is outside the repeater. Here's my button click code:

Private Sub lnkPendingProcessSelected_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles lnkPendingProcessSelected.Click
    For Each rItem As RepeaterItem In rptPendingItems.Items
        If rItem.ItemType = ListItemType.Item Or rItem.ItemType = ListItemType.AlternatingItem Then
            Dim chk As CheckBox = DirectCast(rItem.FindControl("chkPendingItems"), CheckBox)
            If chk.Checked Then
                Dim orderItemId As Integer
                Dim hid As HiddenField = DirectCast(rItem.FindControl("hidPending"), HiddenField)
                orderItemId = CInt(hid.Value)
                My.Application.ManagerFactory.OrderManagerInstance.ChangeOrderItemStatus(orderItemId, Concrete.Cms.DataTransferObjects.OrderItemStatus.Processing)
            End If
        End If
    Next
End Sub

But if you step through this, the checkboxes are found and assigned correctly but their Checked attribute is always False. Anyone have any suggestions as to why state isn't being maintained and what I can do about it?

Yep. Every Page_Load. I think I may need to use some javascript to do this, unfortunately. — Bob Tway
why exactly to you databind on every page_load? my "flow" in this area: first-request databind, receive postback, process the received checkboxes, and after that i can bind the checkboxes. otherwise there will be e.g. a problem if a checkox-value is not present anymore in your datasource ... — karlis

Andrew M Andrew M · Accepted Answer · 2010-11-10T12:43:04

Based on CyberDude's comment, you're probably reseting the values when you databind. If possibly, try using IsPostback to only databind on the first page load.

C#

if(!IsPostBack)
{
    rptPendingItems.DataBind();
}

VB

If Not IsPostBack Then
  rptPendingItems.DataBind()
End If

If that's not possible, or doesn't work, you'll probably have to get and set all of those checkbox values mannually, and persist them against your data set, or in session or summat.

CheckBox Controls in Repeater not maintaining state

2 Answers