EntityConnection can only be constructed with a closed DbConnection

Question

"EntityConnection can only be constructed with a closed DbConnection" This is the problem I get when a try to construct an entityconnection providing an open connection. There is a transactionscope open and I don't want to open a new connection or the transaction would be promoted to a dtc transaction as my understanding is that if I use a single SqlConnection over the multiple entityConnections, I don't need DTC.

So, my code is approximately like this.

Thanks in advance...

    using (TransactionScope transactionScope = new TransactionScope())
{

    using (SqlConnection dwConn = GetDWConnection(user)) 
    {
        dwConn.Open();
        // I need to do some SQlConnection specific actions first

        //EntityConnection specific actions next
        Func1(dwConn);
        Func2(dwConn); //similar to Func1()
        Func3(dwConn); //Similar to Func1()

    }

}
    Func1(SqlConnection dwConn)
    {
        using (EntityConnection conn = GetSQLEntityConnection(sqlConnection))
        {
            ObjectContext objectContext = (ObjectContext)Activator.CreateInstance(objectContextType, new object[] { conn });
            //few actions
        }
    }
    private EntityConnection GetSQLEntityConnection(SqlConnection sqlConnection)
        {
        //few steps
            EntityConnection entityConnection = new EntityConnection(entityConnectionStringBuilder.ToString());

            EntityConnection sqlEntityConnection = new EntityConnection(entityConnection.GetMetadataWorkspace(),sqlConnection);
            return sqlEntityConnection;
        }

Lu55 Lu55 · Accepted Answer · 2012-11-14T18:02:15

Jakub is completely right. You can create neither DbContext nor EntityConnection with opened DbConnection passed to them.

According to Diego B Vega’s post this issue will not be fixed until EF 6 release (here you can vote for it)

The workaround is to open already initialized EntityConnection before any operations involving it.

Given ObjectContext you can open EntityConnection like this:

((EntityConnection)objectContext.Connection).Open();

In case of DbContext the EntityConnection is available from underlying ObjectContext. The code might be like this:

class MyDbContext : DbContext
{
    public MyDbContext (DbConnection connection) 
                  : base (connection, contextOwnsConnection: true)
    {
        ((IObjectContextAdapter)this).ObjectContext.Connection.Open();
    }

    // …
}

class Program
{
    public static void Main()
    {
        var connection = new SqlConnection(CONNECTION_STRING);
        using (var database = new MyDbContext(connection))
        {
            Assert.IsTrue(connection.State == ConnectionState.Open);
        }
        Assert.IsTrue(connection.State == ConnectionState.Closed);
    }
}

EntityConnection can only be constructed with a closed DbConnection

2 Answers