使用LINQ to SQL定期删除一组记录的最佳方法

This is my first crack at a method that is run periodically during the lifetime of my ASP.NET application to clean up expired sessions stored in my database. It seems to work pretty well, but the software engineer in me doesn't feel "right" about this code. I've been working with LINQ to SQL for a few months now, but I'm not very confident in the following code. I'm worried about a few things:This is my first crack at a method that is run