using (var db = new MyDbContext())
using (var tran = db.Database.BeginTransaction()){

    //EF
    var hoge = db.HogeTable.FirstOrDefault();
    hoge.Name = "fuga";
    db.SaveChanges();

    //Dapper
    // create query and params
    db.Database.Connection.Execute(query, params, tran.UnderlyingTransaction);
    tran.Commit();
}