Check for expired date in Gridview - asp.net

Question

I'm fairly new to programming and adjusting some code already written for me. I would like to check if a date in a Gridview(named: playDate) is older than the current date and if so the registration page icon will have it's visibility set to false.
But I'm getting the error:
BC30311: Value of type 'System.Web.UI.Control' cannot be converted to 'Date'
The error appears to be on this line:
playDate = r.Cells(1).FindControl("playDate")
Here's the Front end code:
<asp:SqlDataSource ID="DSCompetitions" runat="server" ConnectionString="<%$ ConnectionStrings:DBConnectionString %>" SelectCommand="SELECT TOP (100) PERCENT tblCompetitions.compID, tblCompetitions.compName, tblCompetitions.playDate, tblCompetitions.venue, tblCompetitions.entryPrice, tblCompetitions.rules, tblCompetitions.maxPlayers
FROM tblCompetitions
ORDER BY tblCompetitions.playDate DESC"></asp:SqlDataSource>
<asp:Gridview ID="gdvCompetitions" width="100%" runat="server" AllowPaging="True" AutoGenerateColumns="False" CssClass="mGrid" DataKeyNames="compID" DataSourceID="DSCompetitions" PageSize="20" AllowSorting="True">
<AlternatingRowStyle CssClass="alt" />
<Columns>
<asp:BoundField DataField="compName" HeaderText="Event" />
<asp:BoundField DataField="playDate" DataFormatString = "{0:dd/MM/yyyy}" HeaderText="Date" />
<asp:BoundField DataField="venue" HeaderText="Venue" />
<asp:BoundField DataField="entryPrice" HeaderText="Entry Fee £" />
<asp:TemplateField ShowHeader="False">
<ItemTemplate>
<asp:HyperLink ID="hypView" runat="server" NavigateUrl='<%# "~/competition-view.aspx?compID=" & Eval("compID").ToString & "&round=1" %>'><asp:Image ID="ImgView" Width="30px" runat="server" ImageUrl="~/files/images/icons/view-icon.png" /></asp:HyperLink>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField ShowHeader="False">
<ItemTemplate>
<asp:HyperLink ID="hypBook" runat="server" NavigateUrl='<%# "~/competition-book.aspx?compID=" & Eval("compID").ToString %>'><asp:Image ID="ImgRegister" Width="30px" runat="server" ImageUrl="~/files/images/icons/register-icon.png" /></asp:HyperLink>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Here's My VB Code:
For Each r As GridViewRow in gdvCompetitions.Rows
If r.RowType = DataControlRowType.DataRow Then 'Execute the code only for datarow, excluding footer and header
Dim playDate As Date
playDate = r.Cells(1).FindControl("playDate")
Dim hypBook As Hyperlink
hypBook = r.Cells(5).FindControl("hypBook")
If date.now > playDate Then
hypBook.visible=false
End If
End If
Next r

Answer 1

You defined playDate as Date then initiated it with Control by playDate = r.Cells(1).FindControl("playDate") , it is not correct.
FindControl will find a control, as you know we can't initiate datetime variable with ASP.Net controls so
Change your code to :
For Each r As GridViewRow in gdvCompetitions.Rows
If r.RowType = DataControlRowType.DataRow Then 'Execute the code only for datarow, excluding footer and header
Dim playDate As Date
playDate = Convert.ToDateTime(r.Cells(1).Text)
Dim hypBook As Hyperlink
hypBook = r.Cells(5).FindControl("hypBook")
If date.now > playDate Then
hypBook.visible=false
End If
End If
Next r
I am not VB.Net programmer, But I am sure my explanation are right and changed code also works.

Answer 2

You'll need to take the value of your control, attempt to convert it to a date ("attempt" because you never know if a non-date could make its way into this column), and then do the comparison.
var playDate = DateTime.Parse(r.Cells(1).Text); // this could throw an error, research DateTime.TryParse()
if (DateTime.Now > playDate)
{
// then...
}
Sorry. Just realized your question is VB. Telerik's code converter is amazing for going from C# to VB, and vice versa.

Answer 3

Instead of
playDate = r.Cells(1).FindControl("playDate")
Use
playDate = r.Cells(1).Text;
FindControl will only work if you have any asp control in grid. For boundfield, you need to get the value of cell.