Question

If I have pooling in the connection string set to true the following code works fine. If turned of it fails with: “MSDC is unavailable”.

Is it just pure luck that both DataContext’s picks the same connection from the pool when pooling is on or is there some kind of coordination done by the TransactionScope?

using(var scope = new TransactionScope())
{
    using(var db = new DataContext(connectionString))
    {
        //Do stuff
    }
    using(var db = new DataContext(connectionString))
    {
        //Do stuff
    }
    scope.Complete();
}

In my real code I can’t currently pass a specific connection to the DataContext but have use the connection string. Also I would like to avoid using the Distributed Transaction Coordinator if possible.

Answer 1

You are getting lucky here because both of your connection strings match, so you are getting the same pooled connection when pooling is enabled. However, the results will be undefined if there are multiple concurrent accesses to connections with this connection string, because you may not get the same pooled connection in the second DataContext instance.

If you have to create two DataContext objects within the same transaction, then you will need to use the DTC. If you can’t use the DTC, then you’ll need to find a way to use only one DataContext object within the transaction.