If you ever get an unspecified error when modifying a dbml file for a linq to sql class one of the possible problems is that you specified using statements outside the name space. ie. the following code will cause the error:
using log4net;
namespace DQR
{
using ValidationUtility;
using System.Linq;
using System;
partial class tblTimeFrame
{
The fix is to move the using statements inside the namespace:
namespace DQR
{
using ValidationUtility;
using System.Linq;
using System;
using log4net;
partial class tblTimeFrame
{
Believe it or not. This fixes the problem and you can click the “View Code” link inside the dbml and be presented with the class. Its not a major flaw, but, it is annoying when you have several classes in the dbml and navigating through the cs file becomes tedious.