Question

When I make the same query twice, the second time it does not return new rows form the database (I guess it just uses the cache).

This is a Windows Form application, where I create the dataContext when the application starts.

How can I force Linq to SQL not to use the cache?

Here is a sample function where I have the problem:

public IEnumerable<Orders> NewOrders() {     return from order in dataContext.Orders            where order.Status == 1            select order;  } 

Answer 1

The simplest way would be to use a new DataContext – given that most of what the context gives you is caching and identity management, it really sounds like you just want a new context. Why did you want to create just the one and then hold onto it?

By the way, for simple queries like yours it’s more readable (IMO) to use ‘normal’ C# with extension methods rather than query expressions:

public IEnumerable<Orders> NewOrders() {     return dataContext.Orders.Where(order => order.Status == 1); } 

EDIT: If you never want it to track changes, then set ObjectTrackingEnabled to false before you do anything. However, this will severely limit it’s usefulness. You can’t just flip the switch back and forward (having made queries between). Changing your design to avoid the singleton context would be much better, IMO.