How to pass Dapper TransactionScope across multiple method

Question

Say I have 2 methods (A and B)

public void A()
{
   using (var connection = Database.GetConnectionString())
   using (var tran = new TransactionScope())
   {
       //do "A"
       tran.Complete()
   }
}

public void B()
{
   using (var connection = Database.GetConnectionString())
   using (var tran = new TransactionScope())
   {
       A(); //call "A"
       //do "B"
       tran.Complete()
   }
}

As you can see, method B need to call A , but both A and B already has its own TransactionScope , in this case, what's the correct way to pass the TransactionScope ?

My Expectation is when method A is called, it will
-. BEGIN TRAN
-. DO "A"
-. COMMIT TRAN

when method B is called, it will
-. BEGIN TRAN
-. DO "A"
-. DO "B"
-. COMMIT TRAN

Any help will be appreciated

Answer 1

TransactionScope is ambient and supports logical nesting by default (aka TransactionScopeOption.Required ); so usually you don't really need to pass it anywhere - as long as you (or Dapper) open(s) the connection inside the scope: it should be included. When two such TransactionScope are nested: committing the inner one effectively does nothing (aborting an inner one dooms the entire transaction) - committing the outer transaction commits the entire thing.

However, frankly I'd usually advise using explicit ADO.NET transactions instead of TransactionScope , and in that case you do need to pass it in; optional parameters are your friend there.

Additionally: note that TransactionScope is almost completely separate to BEGIN TRAN / COMMIT TRAN ; it is an entirely different way of representing transactions (since it needs to support distributed transactions over different systems - typically via either LTM or DTC).