Here is a sample in VB.NET:

<asp:SqlDataSource ConnectionString="<%$ ConnectionStrings:myConn %>" ID="SqlDataSource1"runat="server" SelectCommand="SELECT ContactID, ContactName from Contacts" InsertCommand="INSERT INTO Contacts (ContactName) VALUES (@contactName);SELECT @contactID = Scope_Identity()"
OnInserted="SqlDataSource1_Inserted" >


<InsertParameters>
<asp:Parameter Name="contactName" Type="String" />
<asp:Parameter Direction="Output" Name="contactID" Type="Int32" />
</InsertParameters>


</asp:SqlDataSource>

 Protected Sub SqlDataSource1_Inserted(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.SqlDataSourceStatusEventArgs)
       

 Response.Write("Record Inserted: " + Server.HtmlEncode(e.Command.Parameters("@ContactID").Value.ToString()) + "<br/>")

  End Sub