Single transaction over multiple contexts in Entity Framework 6

Question

We have a scenario to save two entities from two contexts in single transaction.

Step 1 - SetTransaction(firstContext, true);

Step 2 - Save first entity using firstContext.

Step 3 - SetTransaction(secondContext, false);

Step 4 - Save second entity using secondContext

Step 5 - finally commit the transaction.

void function SetTransaction(context, startNewTransaction)
{    
   var currentContext = firstContext;

   if (startNewTransaction)
   {
      var connection = currentContext.GetConnection();
      connection.Open();
      this.dbTransaction = connection.BeginTransaction();
   }

   if (this.dbTransaction != null)
   {
       currentContext.UseTransaction(dbTransaction);
   }
}

While executing Step 3, currentContext.UseTransaction(dbTransaction); line throws the exception as "The transaction passed in is not associated with the current connection. Only transactions associated with the current connection may be used"

Please suggest how to resolve.

Venkat.

Maarten · Accepted Answer · 2016-05-05 07:01:59Z

43

Use the TransactionScope. EF will automatically enlist in a running transaction-scope.

It will require that your connectionstrings are identical.

using (var scope = new TransactionScope()) {
    // Save entity in context A
    using (var contextA = new ContextA()) {
        contextA.Save(...);
        contextA.SaveChanges;
    }
    // Save entity in context B
    using (var contextB = new ContextB()) {
        contextB.Save(...);
        contextB.SaveChanges;
    }
    // Commit tx-scope
    scope.Complete();
}

edited May 5, 2016 at 7:01

answered Aug 14, 2014 at 12:02

Maarten

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5 Comments

MeTitus Over a year ago

identical just in respect to the way transactions should be managed.

broadband Over a year ago

I suppose you meant scope.Complete() instead of scope.Commit(), according to msdn documentation. Commit method doesn't exist.

Seafish Over a year ago

@marco or maarten Could you elaborate on what way the connection strings need to be identical?

Andrew J Over a year ago

It must be the same, otherwise you could (and most likely will) be promoted to DTC.

cdlm Over a year ago

Will this still work if the contexts are created in different methods (and therefore, different scopes)?

Mohammad Reza Sadreddini · Accepted Answer · 2019-01-04 09:35:29Z

1

Using TransactionScope is not recommanded from EF 6 onward. So use:

using (var conn = new SqlConnection("..."))
        {
           conn.Open();

           using (var sqlTxn = conn.BeginTransaction(System.Data.IsolationLevel.ReadCommitted))
           {
               try
               {
                   using (var contextA = new ContextA(conn, contextOwnsConnection: false))
                    {
                        contextA.Database.UseTransaction(sqlTxn);
                        contextA.Save(...);
                        contextA.SaveChanges();
                    }

                    using (var contextB = new ContextB(conn, contextOwnsConnection: false))
                    {
                        contextB.Database.UseTransaction(sqlTxn);
                        contextB.Save(...);
                        contextB.SaveChanges();
                    }

                    sqlTxn.Commit();
                }
                catch (Exception)
                {
                    sqlTxn.Rollback();
                }
            }
        }
    }

Edit: If your dbContext does not have required constructor, You can add another constructor as follow:

public ContextA(): base("name=ConnectionString")
{

}

public ContextA(DbConnection connection) : base(connection, false)
{

}

edited Jan 4, 2019 at 9:35

answered Oct 25, 2018 at 6:14

Mohammad Reza Sadreddini

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3 Comments

joedotnot Over a year ago

This may be well and good, BUT in my Context i could not find a constructor with the overload ContextA(conn, contextOwnsConnection: false)); the only constructor I have is parameterless. I am using EF6 !

joedotnot Over a year ago

thanks BUT not as simple as you suggested. RUNTIME ERROR IS (too long... part 1) Additional information: The context is being used in Code First mode with code that was generated from an EDMX file for either Database First or Model First development. This will not work correctly. To fix this problem do not remove the line of code that throws this exception. If you wish to use Database First or Model First, then make sure that the Entity Framework connection string is included in the app.config or web.config of the start-up project. If you are creating your own DbConnection, then

joedotnot Over a year ago

ERROR part 2: If you are creating your own DbConnection, then make sure that it is an EntityConnection and not some other type of DbConnection, and that you pass it to one of the base DbContext constructors that take a DbConnection. To learn more about Code First, Database First, and Model First see the Entity Framework documentation here: go.microsoft.com/fwlink/?LinkId=394715

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