how to make a label in a nested repeater visible programmatically - asp.net

Question

I have two repeaters, one nested in the other. I'm outputting a list of course titles in the parent repeater and the dates of those courses in the child repeater. This part is working fine. But, not all the course titles necessarily have dates available at any given time, so I want to be able to put a message up under each Course title that currently has no dates saying to check back regularly, blah, blah, blah. I've put the label in the footer template of the nested repeater with visibility=false and am trying to set the visibility=true at the appropriate time in the ItemDataBound Sub. Unfortunately, this is not working. I'm not getting any errors, the label just isn't showing up. I'm really hoping someone can help me out with my code or suggest an alternate way to do this. I'm kinda new to asp.net(VB) and am still struggling a bit. I've never tried nesting repeaters before. Here is my code:
.aspx
<asp:Repeater ID="rptTech" runat="server" >
<HeaderTemplate>
<table class="tableCourses">
</HeaderTemplate>
<ItemTemplate>
<tr>
<td>
<strong><asp:Label runat="server" ID="lblCourseName" Text='<%# Eval("CourseName") %>'></asp:Label></strong>
<br />
<asp:Label runat="server" ID="lblCourseSummary" Text='<%# Eval("Summary") %>'></asp:Label>
<br />
<asp:HyperLink ID="hpCourseMaterial" Visible='<%# CheckCourseMaterial(Eval("CourseMaterial")) %>' NavigateUrl='<%# "/files/Portal_Course_Material/" & Eval("CourseMaterial")%>' Text="Download Course Material" runat="server"></asp:HyperLink>
</td>
</tr>
<tr>
<td>
<asp:Repeater ID="rptTechDates" DataSource='<%#Eval("relCourses") %>' runat="server" >
<HeaderTemplate>
<table>
</HeaderTemplate>
<ItemTemplate>
<tr>
<td>
<strong><asp:Label runat="server" ID="lblDate" Text='<%# CDate(Eval("dteDate")).ToString("dd/MM/yyyy") %>'></asp:Label></strong><br />
<asp:Label runat="server" ID="dteTime" Text='<%# "Time: " & CDate(Eval("dteTime2")).ToString("HH:mm") & " EST" %>'></asp:Label><br />
<asp:HyperLink ID="Register" NavigateUrl='<%# "/Test.aspx?intMeetingID2=" & Eval("pkWebinarID")%>' Text="Register" runat="server"></asp:HyperLink>
</td>
</tr>
</ItemTemplate>
<FooterTemplate>
<tr>
<td>
<asp:Label ID="lblNoCourses" Text="There are no course dates available at this time. Please check back regularly to see any updates." runat="server" Visible="False"></asp:Label>
</td>
</tr>
</table>
</FooterTemplate>
</asp:Repeater>
</td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
And Codebehind:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim curDate As Date = CDate(Now)
'Create the connection
Dim connstring As String
connstring = ConfigurationManager.ConnectionStrings("LPISQLConn").ConnectionString
Using conn As New SqlConnection(connstring)
Dim cmd As New SqlCommand("SELECT foo1, foo2, foo3 FROM tblFoo", conn)
cmd.CommandType = CommandType.Text
Dim ad As New SqlDataAdapter(cmd)
Dim ds As New DataSet()
ad.Fill(ds)
ds.Relations.Add(New DataRelation("relCourses", ds.Tables(0).Columns("fkcrsID"), ds.Tables(1).Columns("webinarID"), False))
rptTech.DataSource = ds.Tables(0)
rptTech.DataBind()
End Using
End Sub
Protected Sub rptTech_ItemDataBound(ByVal sender As Object, ByVal e As RepeaterItemEventArgs)
If e.Item.ItemType = ListItemType.Item OrElse e.Item.ItemType = ListItemType.AlternatingItem Then
Dim drv As DataRowView = TryCast(e.Item.DataItem, DataRowView)
Dim rptTechDates As Repeater = TryCast(e.Item.FindControl("rptTechDates"), Repeater)
rptTechDates.DataSource = drv.CreateChildView("relCourses")
If rptTechDates.Items.Count < 1 And rptTechDates IsNot Nothing Then
If e.Item.ItemType = ListItemType.Footer Then
Dim lblNoCourses As Label = TryCast(e.Item.FindControl("lblNoCourses"), Label)
If lblNoCourses IsNot Nothing Then
lblNoCourses.Visible = True
End If
End If
Else
rptTechDates.DataBind()
End If
End If
End Sub

Answer 1

I would do the following:
Change your ItemDataBoundEvent for the parent repeater to:
Protected Sub rptTech_ItemDataBound(ByVal sender As Object, ByVal e As RepeaterItemEventArgs)
If e.Item.ItemType = ListItemType.Item OrElse e.Item.ItemType = ListItemType.AlternatingItem Then
Dim drv As DataRowView = TryCast(e.Item.DataItem, DataRowView)
Dim rptTechDates As Repeater = TryCast(e.Item.FindControl("rptTechDates"), Repeater)
rptTechDates.DataSource = drv.CreateChildView("relCourses")
rptTechDates.DataBind()
End If
End Sub
Add this to the markup of your child repeater:
OnItemDataBound="rptTechDates_ItemDataBound"
Now add this:
Protected Sub rptTechDates_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.RepeaterItemEventArgs)
If e.Item.ItemType = ListItemType.Footer Then
If DirectCast(DirectCast(e.Item.NamingContainer, Repeater).DataSource, DataTable).Rows.Count = 0 Then
DirectCast(e.Item.FindControl("lblNoCourses"), Label).Visible = True
End If
End If
So, if the number of rows in the child repeater's datasource is 0, then show the label.
EDIT After comment from OP
Protected Sub rptTechDates_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.RepeaterItemEventArgs)
If e.Item.ItemType = ListItemType.Footer Then
If DirectCast(DirectCast(e.Item.NamingContainer, Repeater).DataSource, DataView).Count = 0 Then
DirectCast(e.Item.FindControl("lblNoCourses"), Label).Visible = True
End If
End If

Answer 2

You want to search rptTechDates repeater for the lblNoCourses control. The e.Item.FindControl("lblNoCourses") is searching the rptTech repeater which doesn't exist. See this question to search the control in the rptTechDates footer.
Also, you'll want to call Databind() on the repeater after setting it's DataSource
rptTechDates.DataSource = drv.CreateChildView("relCourses")
rptTechDates.Databind()