query issue within sqldatasource (no replies)

<asp:SqlDataSource ID="SqlDataSource1" runat="server"ConnectionString="<%$ ConnectionStrings:ABCConnectionString %>"

SelectCommand="SELECT * FROM [Data] WHERE ([ActivityName] IN (@ActivityName)) AND ([ID] = @ID)" >

<SelectParameters>
<asp:ControlParameter ControlID="DropDownList_ID" Name="ID"
PropertyName="SelectedValue" Type="Int32" />

<asp:ControlParameter ControlID="LabelHidden" Name="ActivityName"
Type="String" />
</SelectParameters>

</asp:SqlDataSource>

The variable 'LabelHidden' contains a string of values generated from the selected values in the dropdown list: for example: "'PT Support', 'Tools Development'"

Manually, the sql query would run like this, for example:

SELECT * FROM [Data] WHERE ([ActivityName] IN ('PT Support', 'Tools Development')) AND ([ID] = 4)

It runs correctly when I use this query in SQL Management Studio, but will not run correctly from within my SQLDataSource1.

When I do a trace, returns

exec sp_executesql N'SELECT * FROM [Data] WHERE ([ActivityName] IN (@ActivityName)) AND ([ID] = @ID)',N'@ID int,@ActivityName nvarchar(51)',@ID=4,@ActivityName=N'''PT Support'', ''Tools Development'''