Logging every data change with Entity Framework

Question

There is a need from a customer to log every data change to a logging table with the actual user who made the modification. The application is using one SQL user to access t

Answer 1

Simply force an execution of the SET CONTEXT_INFO by using your DbContext or ObjectContext:

...
FileMoverContext context = new FileMoverContext();
context.SetSessionContextInfo(Environment.UserName);
...
context.SaveChanges();

FileMoverContext inherits from DbContext and has a SetSessionContextInfo method. Here is what my SetSessionContextInfo(...) looks like:

public bool SetSessionContextInfo(string infoValue)
{
   try
   {
      if (infoValue == null)
         throw new ArgumentNullException("infoValue");

      string rawQuery =
                   @"DECLARE @temp varbinary(128)
                     SET @temp = CONVERT(varbinary(128), '";

      rawQuery = rawQuery + infoValue + @"');
                    SET CONTEXT_INFO @temp";
      this.Database.ExecuteSqlCommand(rawQuery);

      return true;
   }
   catch (Exception e)
   {
      return false;
   }
}

Now you just set up a database trigger which can access the CONTEXT_INFO() and set a database field using it.