選擇類別庫, 名稱: MyToolkit
點選MyToolkit方案按下滑鼠右鍵 <加入>< 新增項目>
選擇: <類別>, 輸入GenericTool.cs
加入保留字<public>, 以便其他專案加入參考後看得到
1: namespace MyToolkit
2: {3: public class GenericTool
4: {5: public static int Finder<T>(T[] items, T item)
6: {7: for (int i = 0; i < items.Length; i++)
8: {9: if(items[i].Equals(item))
10: {11: return i;
12: } 13: }14: return -1;
15: } 16: } 17: }
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加入另一個新的專案, 測試剛才寫好函式庫中的 Finder泛型函式
針對int型別
1: int ind;
2: int[] a = new int[8] { 1, 23, 24, 5, 2, 4, 33, 4 };
3: int b = 5;
4: ind = GenericTool.Finder<int>(a, b);
5: MessageBox.Show( b.ToString() + "在a[]中 第 " + ind.ToString() + " 位置" );
執行結果:
針對char型別
1: char[] c = new Char[5] { 'a', 'b', 'c', 'd', 'e' };
2: char d = 'e';
3: ind = GenericTool.Finder<char>(c, d);
4: MessageBox.Show(d + "在c[]中 第 " + ind.ToString() + " 位置");
1: string[] f = new string[3] { "你", "我", "他" };
2: string g = "我";
3: ind = GenericTool.Finder<string>(f, g);
4: MessageBox.Show(d + "在f[]中 第 " + ind.ToString() + " 位置");
1: DateTime[] h = new DateTime[3] { new DateTime(2015, 2, 14), new DateTime(2015, 2, 15), new DateTime(2015, 2, 16) };
2: DateTime i = new DateTime(2015,2,15);
3: ind = GenericTool.Finder<DateTime>(h, i);4: MessageBox.Show(i.ToShortDateString() + "在h[]中 第 " + ind.ToString() + " 位置");
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public class [類別名稱]<類型參數T>
{
public T 欄位名稱1
public T 欄位名稱2
… …
}
開啟GenericTool.cs, 加入一個泛型類別 Employee
1: #region 員工基本資料類別
2: public class Employee<T>
3: {4: public T num;
5: public T name;
6: public T sex;
7: public T age;
8: public T birthday;
9: public T salary;
10: }11: #endregion
完成如下
更新編譯函式庫MyToolkit
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撰寫一個範例測試, 並加入參考MyToolkit
以Employee.num為例, 等號右邊型別為int, 因此原本employ.num為object型態可以動態更新成int型態
同理, birthday等號右邊為DateTime, 所以employee.birthday就會變成DateTime型態
心得:定義Employ為泛型類別, 這樣有個好處是時不用擔心到時候實體化之後傳入內容資料型態,
是否與當初設計的資料型態相吻合, 有可能設計時num欄位時想的是int就夠用, 結果使用時該死傳入double就掛點啦!!!
泛型可以在等號右邊傳入時候, 才決定其真正的資料型態
1: Employee<object> employee = new Employee<object>(); //實例化泛型類物件
2: employee.num = 1;3: employee.name = "小王";
4: employee.sex = "渣啵";
5: employee.age = 25;6: employee.birthday = Convert.ToDateTime("1995/11/02");
7: employee.salary = 1000F;8: //-------------------------------------
9: textBox1.Text = employee.num.ToString(); 10: textBox2.Text = employee.name.ToString(); 11: textBox3.Text = employee.sex.ToString(); 12: textBox4.Text = employee.age.ToString(); 13: textBox5.Text = employee.birthday.ToString(); 14: textBox6.Text = employee.salary.ToString();
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繼承泛型類別
假設Employee想要增加3個欄位 住址, E-mail, 小孩個數,
直覺的想法是直接修改Employee類別,
不過這樣原本專案中有用到Employee類別也同時多了一些沒用到的欄位,
更好的最法可以新增一個類別EmployeInfo繼承Employee,
這樣新的專案就可以依照需求選擇合適的類別
1: #region 員工基本資料和更新資訊類別
2: public class EmployeeInfo<T> : Employee<T>
3: {4: public T address; // 地址
5: public T eMail; // 電子信箱
6: public T children; // 小孩個數
7: }8: #endregion
更新編譯函式庫MyToolkit
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撰寫一個範例測試, 並加入參考MyToolkit
1: EmployeeInfo<object> employeeInfo = new EmployeeInfo<object>(); //實例化繼承泛型類物件
2: employeeInfo.num = 1;3: employeeInfo.name = "小王";
4: employeeInfo.sex = "渣啵";
5: employeeInfo.age = 25;6: employeeInfo.birthday = Convert.ToDateTime("1995/11/02");
7: employeeInfo.salary = 1000F;8: employeeInfo.address = "台北市中山區南京東路二段98號";
9: employeeInfo.eMail = "me1237guy@yahoo.com.tw";
10: employeeInfo.children = 2;11: //-----------------------------------------------
12: textBox1.Text = employeeInfo.num.ToString(); 13: textBox2.Text = employeeInfo.name.ToString(); 14: textBox3.Text = employeeInfo.sex.ToString(); 15: textBox4.Text = employeeInfo.age.ToString(); 16: textBox5.Text = employeeInfo.birthday.ToString(); 17: textBox6.Text = employeeInfo.salary.ToString(); 18: textBox7.Text = employeeInfo.address.ToString(); 19: textBox8.Text = employeeInfo.eMail.ToString(); 20: textBox9.Text = employeeInfo.children.ToString();執行如下:
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