DataSource Controls :: Use Date Datatype In SQL Server 2008?

I want to filter by database result based on the current date. I have a grid layout which will display the result based on the current date. I am using parameterized query for getting the result but it is not working.given below is the query i am using

<asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>"
SelectCommand="SELECT TestID, Title, Description FROM aspnet_Test WHERE (Date
=@testdate)">
<SelectParameters>
<asp:Parameter Name="testdate" DbType="Date" />
</SelectParameters>
</asp:SqlDataSource>

and the result should filter on the basis of testdate

String testday, testmonth, testyear,testdate;
testday = System.DateTime.Now.Day.ToString();
testmonth = System.DateTime.Now.Month.ToString();
testyear = System.DateTime.Now.Year.ToString();
testdate.Text = testyear.ToString() + "-" + testmonth.ToString() + "-" + testday.ToString();

but this is not working .It is not showing any error but i am not getting any output.