Asp.net VB Test value in GridView - asp.net

Question

I have found heaps of solutions for this in C# but when you are dealing with FindControls and trying to pull a value out of the GridView the C# doesn't help and the translated code doesn't work.
I have this gridview:
<asp:GridView ID="WIPListGrid" runat="server" DataSourceID="WIPDataSource"
CssClass="site" AutoGenerateColumns="False"
Width="95%" DataKeyNames="Masterid_Action" onrowdatabound="WIPListGrid_RowDataBound">
<Columns>
<asp:BoundField DataField="Action Due Date" HeaderText="Action Due Date"
SortExpression="Action Due Date" />
</Columns>
</asp:GridView>
and I have this in vb:
Protected Sub WIPListGrid_RowDataBound(sender As Object, e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles WIPListGrid.RowDataBound
Dim DueDate As Label = DirectCast(e.Row.FindControl("Action Due Date"), Label)
'do what ever you want to do here using the value of your label
MsgBox("Due Date = " & DirectCast(e.Row.FindControl("Action Due Date"), Label))
End Sub
Error message is Operator & is not defined for types 'String' and 'System.Web.UI.WebControls.Label'
This is a remedial example of what I ~really~ want to do. Above I just want to display what is contained in DueDate to see what format it is in so I can test it against other values. but it won't work. It appears the the contents of Action Due Date is not a string... so, what am I missing?
I have tried to set the value equal to a string but got the same problem, the Label isn't a string...
How do I find out what's in there in order to evaluate it?
17/01/2013 edit: Keeping this active as I still do not have my issue resolved.
18/01/2013 edit:
vb.net code is now
Protected Sub WIPListGrid_ROWDataBound(sender as Object,
e As System.Web.UI.Webcontrols.GridViewRowEventArgs) Handles WIPListGrid.RowDataBound
Dim DueDate As Label = DirectCast(e.Row.FindControl("Action Due Date"), Label)
'do what ever you want to do here using the value of your label
MsgBox("Due Date = " & DueDate.Text)
End Sub
But now I get an error that the Object isn't instantiated and its pointing to the msgbox line in the code. I thought that I instantiated it when I dim it as a Label...
The official error is:
"Object reference not set to an instance of an object."
the troubleshooting tips say to
1) Use the "new" keyword to create an object instance
2) Check to determine if the object is null before calling the method
I tried the "new" option and got an error that says the variable has already been declared.
So now I want to check to determine if the object is null and can't figure out how.
I've tried testing: DirectCast(e.Row.FindControl("action due date"), Label) <> ""
but got an error: Overload resolution failed because no accessible '<>' can be called with these arguments.
How do I test to see if the object is null?
The value shouldn't be null (the database doesn't allow it to be null), BUT this could be the crux of my issue...
Any help?

Answer 1

When working with controls, you have to point out that you want that value inside your control.
In your case, you're just going for the label-control itself (not the text inside).
For example:
Dim myControl As Label = DirectCast(e.Row.FindControl("myControl"), Label)
MsgBox("MyText = " & myControl.Text)
Hope this helps.

Answer 2

The problem is you are using a BoundField so there is no control to find. Change it to a templatefield and this will work.
<asp:GridView ID="WIPListGrid" runat="server" DataSourceID="WIPDataSource"
CssClass="site" AutoGenerateColumns="False"
Width="95%" DataKeyNames="Masterid_Action" onrowdatabound="WIPListGrid_RowDataBound">
<Columns>
<asp:TemplateField HeaderText="Action Due Date">
<ItemTemplate>
<asp:Label ID="lblActionDueDate" runat="server" Text='<%# Bind("[Action Due Date]") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
For Your Row DataBound Event use
Dim DueDateLabel As Label = DirectCast(e.Row.FindControl("lblActionDueDate"), Label)
'Check Label Exists
If DueDateLabel IsNot Nothing Then
Dim DueDateText As String = DueDateLabel.Text
MsgBox(String.Format("Due Date {0}", DueDateText))
End If