LINQ to SQL maps "out" parameters in SPROCs as reference parameters (ref keyword), and for value types declares the parameter as nullable.

For example, consider the below "GetCustomerDetails" SPROC which takes a CustomerID as an input parameter, and which returns the company name as an output parameter in addition to its order history as a query result:

Figure 15

If we drag the above SPROC onto our "Order" class in the LINQ to SQL designer, we could then write the below code to call it:

VB:

Figure 16

C#:

Figure 17

Notice in the code above how the SPROC helper method returns back a sequence of Order objects - but also then returns the CompanyName as an output parameter to the helper method.