LinqDataSource and DateTime Format - asp.net

Question

I'm trying to create a LinqDataSource to bind to a DropDownList in an ASP.NET form. I only want to show the elements according to a date (which is one of the fields in the database).
Basically, the elements I want to show are the ones that will happen in the futures (i.e. after DateTime.Now).
I was trying the following markup :
<asp:DropDownList runat="server" ID="DropDownList1"
AppendDataBoundItems="True" DataSourceID="LinqDataSource1"
DataTextField="TextField" DataValueField="ValueField">
</asp:DropDownList>
<asp:LinqDataSource ID="LinqDataSource1" runat="server"
ContextTypeName="DataContext1" TableName="Table"
Where="DateField >= #DateField">
<WhereParameters>
<asp:Parameter DefaultValue="DateTime.Now" Name="DateField"
Type="DateTime" />
</WhereParameters>
</asp:LinqDataSource>
I'm getting a format exception saying that "The string was not recognized as a valid DateTime" when I try to run it. However, the dates in my database seem to be fine, because a DateTime.Parse works perfectly on them. The DateField is of type datetime in SQL.
What am I missing here?
Thanks!

Answer 1

The DefaultValue was what was wrong with the code as was suggested by the others.
However, setting the DefaultValue to
"<%# DateTime.Now %>"
like Andomar suggested (which would make the markup look something like this :
<WhereParameters>
<asp:Parameter DefaultValue="<%# DateTime.Now %>" Name="DateField" Type="DateTime" />
</WhereParameters>
will not work either because DataBinding expressions are only supported on objects that have a DataBinding Event, and neither Parameter or ControlParameter have one.
For a String, it's fairly easy to create a TextBox or Label and put the <%# %> expression in the value of that new field (more details here), but it was a bit more complicated with a DateTime value, as comparing an SQL DateTime with a .NET DateTime caused an exception.
It can be done quite easily in the Page_Load event by using
DataContext DataContext1 = new DataContext();
var c = from a in DataContext1.Field
where a.DateField >= DateTime.Now
select a;
DropDownList.DataSource = c;
DropDownList.DataBind();

Answer 2

I suspect it is failing on the DefaultValue.

Answer 3

Try:
DefaultValue="<%# DateTime.Now %>"