Simple Factory mode (Introduction to design mode)

Before you learn a formal design pattern, start with an appetizer, the simple factory model. The following will design a calculator applet using the Simple factory model:

First, the operational base class (operation)

1      Public Abstract classOperation2     {3          Public DoubleNumA {Set;Get; }4          Public DoubleNumB {Set;Get; }5          Public Virtual DoubleGetResult ()6         {7             return 0;8         }9}

Second, the method of operation (+,-)

1      Public classoperationadd:operation2     {3          Public Override DoubleGetResult ()4         {5             Doubleres =0;6res =Base. NumA +Base. NumB;7             returnRes;8         }9     }Ten  One      Public classoperationsub:operation A     { -          Public Override DoubleGetResult () -         { the             Doubleres =0; -res =Base. NumA-Base. NumB; -             returnRes; -         } +}

Iii. Object Creation Classes

1      Public classoperationfactory2     {3          PublicOperation CreateOperation (stringop)4         {5Operation res =NULL;6             Switch(OP)7             {8                  Case "+":9res =NewOperationadd ();Ten                      Break; One                  Case "-": Ares =Newoperationsub (); -                      Break; -             } the             returnRes; -         } -}

Iv. implementation

1     /// <summary>2     ///Simple Factory mode-place the selection of the instance in the factory class3     /// </summary>4      Public classDosimplefactory:designpattern5     {6          Public Override voidExefun ()7         {8Console.WriteLine ("Please enter operator: + 、-、 *,/");9Operation OT =Newoperationfactory (). CreateOperation (Console.ReadLine ());TenOt. NumA =2; OneOt. NumB =4; A             Doubleres =ot. GetResult (); -Console.Write (string. Format ("The result is: {0}", Res)); -         } the}

Simple Factory mode (Introduction to design mode)