Question

I have a user control that contains a repeater. The repeater contains some control, including a dropDownList with id ‘ddlPallet’. The repeater is bound to a dataset in the user controls’ Page_Load event.

I’m using the ItemDataBound event of the repeater to change the SelectedValue of the dropdownlist based on a value from the dataset.

The problem I’m having is that when the page renders, ALL of the dropdownlists’ selectedValue are set to the last selectedValue specified – i.e. If there are 8 rows in the dataset and row 8 is ‘N’ then the selected index of all instances of ‘ddlPallet’ will have a selectedValue of ‘N’

Here’s my ItemDataBound code:

Protected Sub rptCavities_ItemDataBound(sender As Object, e As System.Web.UI.WebControls.RepeaterItemEventArgs) Handles rptCavities.ItemDataBound
    If e.Item.ItemType = ListItemType.Item Or e.Item.ItemType = ListItemType.AlternatingItem Then
        Dim ddl As DropDownList
        ddl = e.Item.FindControl("ddlPallet") 'get the dropdown
        ddl.Items.AddRange(Me._arrPallets) 'add items
        Dim drv As DataRowView = CType(e.Item.DataItem, DataRowView) 'get the data row being bound
        Dim sv As String = "" 'get the value of the 'pallet' column from the dataset
        If Trim(drv("Pallet").ToString()) <> "" Then
            sv = drv("Pallet").ToString()
        Else
            sv = "N"
        End If
        ddl.SelectedValue = sv 'set the selected value of the dropdown list for this item
        'debug
        System.Diagnostics.Debug.WriteLine("----")
        System.Diagnostics.Debug.WriteLine("Control ID: " & ddl.ID)
        System.Diagnostics.Debug.WriteLine("Control Client ID: " & ddl.ClientID)
        System.Diagnostics.Debug.WriteLine(ddl.SelectedIndex.ToString() & " - " & ddl.SelectedItem.ToString() & " - " & ddl.SelectedValue)
        System.Diagnostics.Debug.WriteLine("")
    End If
End Sub

The debug output shows that the appropriate SelectValue is being set per item/per dropDownList:

---

Control ID: ddlPallet
Control Client ID: Cure1_rptCavities_ctl01_ddlPallet
4 – FL – FL

---

Control ID: ddlPallet
Control Client ID: Cure1_rptCavities_ctl02_ddlPallet
3 – EP – EP

---

Control ID: ddlPallet
Control Client ID: Cure1_rptCavities_ctl03_ddlPallet
0 – N – N

..etc.

This is driving me nuts. I assume I have some kind of scoping error that is causing the last-set index value to apply to all instances of the dropDownList in the repeater, but I’m having no luck figuring out where or why. If I bind the same data to a label in the ASCX file using “Text='<%#Container.DataItem(“Pallet”)%>'” the correct data is displayed.

Answer 1

It may be because you’re adding the same items to the drop down list in every case, rather than binding the dropdownlist to the source data. This way, they all share a common set of items, and if you set Selected = true to one item, it’ll be true for every dropdownlist that contains that item.

Potentially an interesting technique, but probably not what you want.