I am trying to configure a sqldatasource control using the where clause to grab a single record with a certain UserId. Teh UserId is stored in a variable of type System.Gui and I cant seem to figure out how to do this. Can someone give me a hand please?

I'm assuming that your working with membership , and you want to show the Data related to current user ,

you can  add a where clause to the SqlDataSource  Select Command in Selecting event :

    Protected Sub SqlDataSource1_Selecting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.SqlDataSourceSelectingEventArgs) Handles SqlDataSource1.Selecting
        SqlDataSource1.SelectCommand += String.Format("  WHERE (UserID = {0})", Membership.GetUser().ProviderUserKey.ToString())
    End Sub

Thanks for your help. I am trying to display some information from a different table and a different user. The code you provided helped a lot, but it still is not loading the data into the detailsview control. Here is what i have:

<asp:DetailsView ID="DetailsViewPersonal" runat="server" Height="50px"
                Width="125px" BackColor="White" BorderColor="White"
                BorderStyle="Ridge" BorderWidth="2px" CellPadding="3" CellSpacing="1"
                DataSourceID="SqlDataSourcePersonal" GridLines="None">
                <FooterStyle BackColor="#C6C3C6" ForeColor="Black" />
                <RowStyle BackColor="#DEDFDE" ForeColor="Black" />
                <PagerStyle BackColor="#C6C3C6" ForeColor="Black" HorizontalAlign="Right" />
                <HeaderStyle BackColor="#4A3C8C" Font-Bold="True" ForeColor="#E7E7FF" />
                <EditRowStyle BackColor="#9471DE" Font-Bold="True" ForeColor="White" />
            </asp:DetailsView>

<asp:SqlDataSource ID="SqlDataSourcePersonal" runat="server"
        ConnectionString="<%$ ConnectionStrings:ModelsFinderConnectionString %>"
        SelectCommand="SELECT [Age], [DOB], [Gender], [ChestSize], [CupSize], [Waist], [Height], [Hips], [Weight], [HairColor] FROM [Personal_Stats]"
        onselecting="SqlDataSourcePersonal_Selecting">
    </asp:SqlDataSource>

 protected void SqlDataSourcePersonal_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
    {
        SqlDataSourcePersonal.SelectCommand += String.Format("  WHERE (UserId = {0})", ThisUserId.ToString());
    }

the detailsview shows the headers on the left but does not fill the column on the right with the information. What am i doing wrong?

Geek-O:

 protected void SqlDataSourcePersonal_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
    {
        SqlDataSourcePersonal.SelectCommand += String.Format("  WHERE (UserId = {0})", ThisUserId.ToString());
    }

I don't think this is the way how you should be doing this.

First you need to change the query in your select command directly in the SQL data source declaration:

Geek-O:

SelectCommand="SELECT [Age], [DOB], [Gender], [ChestSize], [CupSize], [Waist], [Height], [Hips], [Weight], [HairColor] FROM [Personal_Stats]"

SelectCommand="SELECT [Age], [DOB], [Gender], [ChestSize], [CupSize], [Waist], [Height], [Hips], [Weight], [HairColor] FROM [Personal_Stats]  where UserId = @UserId"

Then you need to declare this parameter in the select parameter's collection for the data source.

<SelectParameters>
                    <asp:Parameter Name="UserId" Type="String" />
</SelectParameters>

Then in the data source selecting event modify your code like:

  protected void SqlDataSourcePersonal_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
    {
        e.Command.Parameters["@UserId"].Value = ThisUserId.ToString();
    }

There are of course other ways of using the parameters in your data source commands ( select, insert, update, delete ) for that you may refer to the MSDN.