interface DB
{
void ProcessDatabaseTemplateMethod();
}

//------------------------------------------
// Template Method, abstract parent:
abstract class TemplateMethodAbstractClass
{
// abstract methods
  abstract public void Open();
  abstract public void Close();
// The Template method
public void ProcessDatabaseTemplateMethod()
{
  Console.WriteLine(" TemplateMethodAbstractClass.TemplateMethod()");
   Open();
   Close();
}
}
//------------------------------------------
// Factory Method: The database processing
// concrete realization classes
class PostgreDB : TemplateMethodAbstractClass, DB
{
  public override void Open() { Console.WriteLine("PostgreDB.Open()"); }
  public override void Close() { Console.WriteLine("PostgreDB.Close()"); }
}
class SQLiteDB : TemplateMethodAbstractClass, DB
{
  public override void Open() { Console.WriteLine("SQLiteDB.Open()"); }
  public override void Close() { Console.WriteLine("SQLiteDB.Close()"); }
}
//------------------------------------------
// Factory Method: The Fabric class implementation
class FabricDB
{
public DB GetDB (TypeDB typeDB)
{
  DB ret = null;
  switch ( typeDB )
  {
    case TypeDB.SQLite : ret = new SQLiteDB(); break;
    case TypeDB.PostgreSQL : ret = new PostgreDB(); break;
    default : break;
  }
return ret;
}
}
//------------------------------------------
// The client class implementation
  class TemplateMethodClass
{
  public static void Main()
{
// Factory method:
  FabricDB fd = new FabricDB();
  DB postgreDB = fd.GetDB( TypeDB.PostgreSQL );
  DB sqliteDB = fd.GetDB( TypeDB.SQLite );
   sqliteDB.ProcessDatabaseTemplateMethod();
  postgreDB.ProcessDatabaseTemplateMethod();
   Console.Read();
  }
}