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新增一個抽象類別(範本方法)，裡面定義驗算法的骨架TemplateMethod()，包含3個步驟proc1()、proc2()、proc3()；這些步驟實作延遲至繼承的子類別去實作，增加了使用上的彈性。
1: abstract class AbstractClass
2: {3: protected abstract void proc1();
4: protected abstract void proc2();
5: protected abstract void proc3();
6: public void TemplateMethod()
7: { 8: proc1(); 9: proc2(); 10: proc3();11: MessageBox.Show("TemplateMethod");
12: } 13: }
ConcreteClassA和ConcreteClassB分別繼承AbstractClass，因此需要覆寫(override)剛剛父類別的抽象方法:包含3個步驟proc1()、proc2()、proc3()；
ConcreteClassA: 1. 讀入影像 2.彩色轉灰階 3. 灰階轉黑白
1: class ConcreteClassA : AbstractClass
2: {3: protected override void proc1()
4: {5: MessageBox.Show("具體A proc1=imread");
6: //throw new NotImplementedException();
7: }8: protected override void proc2()
9: {10: MessageBox.Show("具體A proc2=rgb2gray");
11: //throw new NotImplementedException();
12: }13: protected override void proc3()
14: {15: MessageBox.Show("具體A proc3=gray2bw");
16: //throw new NotImplementedException();
17: } 18: }ConcreteClassB: 1.讀入影像 2.金字塔縮小 3.金字塔放大
1: class ConcreteClassB : AbstractClass
2: {3: protected override void proc1()
4: {5: MessageBox.Show("具體B proc1=imread");
6: //throw new NotImplementedException();
7: }8: protected override void proc2()
10: MessageBox.Show("具體B proc2=pyrmidDown");
11: //throw new NotImplementedExcepti
9: {on(); 12: }13: protected override void proc3()
14: {15: MessageBox.Show("具體B proc3=pyrmidUp");
16: //throw new NotImplementedException();
17: } 18: }客戶端程式
AbstractClass imgProc;
影像處理1. 讀入影像 2.彩色轉灰階 3. 灰階轉黑白
imgProc = new ConcreteClassA(); <---------多型
或是
影像處理1.讀入影像 2.金字塔縮小 3.金字塔放大
imgProc = new ConcreteClassB();
1: AbstractClass imgProc;2: private void button1_Click(object sender, EventArgs e)
3: {4: imgProc = new ConcreteClassA();
5: imgProc.TemplateMethod(); 6: } 7: 8: private void button2_Click(object sender, EventArgs e)
9: {10: imgProc = new ConcreteClassB();
11: imgProc.TemplateMethod(); 12: }------------------------------------
如果把父類別中proc1()、proc2()、proc3()從abstract變成virtual，則繼承的子類別可以不需要實作(覆寫)全部函式，儘管TemplateMethod中有定義proc3()
1: namespace TemplateCMethodDemo
2: {3: abstract class AbstractClass
4: {5: protected virtual void proc1(){}
6: protected virtual void proc2(){}
7: protected virtual void proc3(){}
8: public void TemplateMethod()
9: { 10: proc1(); 11: proc2(); 12: proc3();13: MessageBox.Show("TemplateMethod");
14: } 15: }16: class ConcreteClassA : AbstractClass
17: {18: protected override void proc1()
19: {20: MessageBox.Show("具體A proc1=imread");
21: //throw new NotImplementedException();
22: }23: protected override void proc2()
24: {25: MessageBox.Show("具體A proc2=rgb2gray");
26: //throw new NotImplementedException();
27: }28: //protected override void proc3()
29: //{
30: // MessageBox.Show("具體A proc3=gray2bw");
31: // //throw new NotImplementedException();
32: //}
33: }34: class ConcreteClassB : AbstractClass
35: {36: protected override void proc1()
37: {38: MessageBox.Show("具體B proc1=imread");
39: //throw new NotImplementedException();
40: }41: protected override void proc2()
42: {43: MessageBox.Show("具體B proc2=pyrmidDown");
44: //throw new NotImplementedException();
45: }46: protected override void proc3()
47: {48: MessageBox.Show("具體B proc3=pyrmidUp");
49: //throw new NotImplementedException();
50: } 51: } 52: }參考資料:
1. 大話設計模式, 作者: 程杰
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