Question

I followed this question stuck on changing each row color during run-time in listview in asp.net based on database entries and tried to do the same in VB but i am getting some unexplained errors, like Object reference not set to an instance of an object
most likely for this row =>
Dim cell As HtmlTableRow = DirectCast(e.Item.FindControl(“MainTableRow”), mlTableRow)

Please let me know if there is any better way / correct way to do this in VB?

Protected Sub ListView2_ItemDataBound1(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewItemEventArgs) _
Handles ListView2.ItemDataBound
    If e.Item.ItemType = ListViewItemType.DataItem Then
        Dim dataitem As ListViewDataItem = DirectCast(e.Item, ListViewDataItem)
        Dim mstorename As String = DataBinder.Eval(dataitem.DataItem, "Store")
        If mstorename = "A1" Then
            Dim cell As HtmlTableRow = DirectCast(e.Item.FindControl("MainTableRow"), mlTableRow)
            cell.BgColor = #E0E0E0
        End If
    End If
End Sub

Many thanks for your help.

dk

Answer 1

For this to work, you must ensure that you provide MainTableRow id to tr element and mark it as runat="server" i.e. make sure that your mark-up (html) is something like

<ItemTemplate>
   <tr id="MainTableRow" runat="server">
   ...

A different (and IMO, simpler) approach will be using data-binding expressions. For example, in your markup, use

<ItemTemplate>
       <tr class='<%# GetRowStyle(Container.DataItem) #>'>

And in code-behind, have a protected function to provide CSS class based on data (a example c# function will be)

protected string GetRowStyle(object item)
{
   var store = DataBinder.Eval(item, "Store");
   if (store == "A1")
   {
      return "altRow";
   }
   else
   {
     return "row";
   }
}

And lastly, define those css classes (row, altRow) as per your needs.