Delphi中的泛型

别和我逼逼 發表於 2021-7-20 13:31:00

-------------Delphi7没有泛型
开发环境是Delphi XE  （是XE，不是XE2，不是XE10）
-------------------
 
--------------Unit 开始-
<div class="cnblogs_code">
<pre>1 unit Unit1;
2
3 interface
4
5 uses
6 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
7 Dialogs, StdCtrls, ExtCtrls, TypInfo; //,Generics.Collections
8
9 type
 10 TForm1 = class(TForm)
 11 Button1: TButton;
 12 Button2: TButton;
 13 Button3: TButton;
 14 Bevel1: TBevel;
 15 Button4: TButton;
 16 Button5: TButton;
 17 procedure Button1Click(Sender: TObject);
 18 procedure Button2Click(Sender: TObject);
 19 procedure Button3Click(Sender: TObject);
 20 procedure Button4Click(Sender: TObject);
 21 procedure Button5Click(Sender: TObject);
 22 private
 23 { Private declarations }
 24 public
 25 { Public declarations }
 26 end;
 27
 28 Tmycalss=class
 29 private
 30 type
 31 TMyRecord=record
 32 s:string;
 33 end;
 34 public
 35 Myr:TmyreCord;
 36 end;
 37 {
 38 泛型：声明定义的时候看上去就是把类型当成形参一样的东西用T表示，当然也可以用其他的字符代替;
 39 在使用的时候把<T> 中的T看成是实参，实参是类型
 40 比如:
 41 var
 42 ss:TMygeneric<String> ;
 43 }
 44 TMygeneric<T> =array[0..9] ofT ; //TMygeneric<sss> =array ofsss;这个也可以的
 45
 46 TmyGenericClass<T>=class(Tobject)
 47 private
 48 FIDCode:T;
 49 public
 50 end;
 51
 52 TmyGenericClass_A<T:Class> =class(TmyGenericClass<T>)
 53 private
 54 FIDCode_A:T;
 55 end;
 56 var
 57 Form1: TForm1;
 58
 59 implementation
 60
 61 {$R *.dfm}
 62
 63 procedure TForm1.Button1Click(Sender: TObject);
 64 var
 65 ss:TMygeneric<String>; //泛型
 66 i:Integer;
 67 begin
 68 fori:=0 to 9 do
 69 begin
 70 ss:=IntToStr(i);
 71 end;
 72 end;
 73
 74 procedure TForm1.Button2Click(Sender: TObject);
 75 var
 76 Myc:Tmycalss;
 77 begin
 78 Myc:=Tmycalss.Create;
 79 Myc.Myr.s:='8888';
 80 ShowMessage(Myc.Myr.s);//看下类中类
 81 FreeAndNil(Myc);
 82 end;
 83
 84 procedure TForm1.Button3Click(Sender: TObject);
 85 var
 86 MyArrayc:TMygeneric<Tmycalss>;//泛型
 87 i:Integer;
 88 begin
 89 fori:=0 to 9 do
 90 begin
 91 MyArrayc:=Tmycalss.Create;
 92 MyArrayc.Myr.s:='498789';
 93 end;
 94 fori:=0 to 9 do
 95 begin
 96 FreeAndNil(MyArrayc);
 97 end;
 98 end;
 99
100 procedure TForm1.Button4Click(Sender: TObject);
101 var
102 vClass:TmyGenericClass<String>;
103 begin
104 vClass:=TmyGenericClass<String>.Create;
105 vClass.FIDCode:='978978';
106 ShowMessage(vClass.FIDCode );
107 FreeAndNil(vClass);
108 end;
109
110 procedure TForm1.Button5Click(Sender: TObject);
111 var
112 vClass_A:TmyGenericClass_A<Tmycalss> ;
113 begin
114 vClass_A:=TmyGenericClass_A<Tmycalss>.Create;
115 vClass_A.FIDCode_A:=Tmycalss.Create;
116 vClass_A.FIDCode_A.Myr.s:='456465';
117 ShowMessage(vClass_A.FIDCode_A.Myr.s);
118 FreeAndNil(vClass_A.FIDCode_A);
119 FreeAndNil(vClass_A);
120 end;
121
122 end.</pre>
</div>
 
-------------Unit结束-----
 
--------Form 开始--------
<div class="cnblogs_code">
<pre> 1 object Form1: TForm1
 2 Left = 754
 3 Top = 463
 4 BorderStyle = bsDialog
 5 Caption = 'Form1'
 6 ClientHeight = 185
 7 ClientWidth = 308
 8 Color = clBtnFace
 9 Font.Charset = DEFAULT_CHARSET
10 Font.Color = clWindowText
11 Font.Height = -11
12 Font.Name = 'Tahoma'
13 Font.Style = []
14 OldCreateOrder = False
15 Position = poDesigned
16 PixelsPerInch = 96
17 TextHeight = 13
18 object Bevel1: TBevel
19 Left = 152
20 Top = 8
21 Width = 9
22 Height = 159
23 end
24 object Button1: TButton
25 Left = 48
26 Top = 24
27 Width = 75
28 Height = 25
29 Caption = 'Button1'
30 TabOrder = 0
31 OnClick = Button1Click
32 end
33 object Button2: TButton
34 Left = 48
35 Top = 72
36 Width = 75
37 Height = 25
38 Caption = 'Button2'
39 TabOrder = 1
40 OnClick = Button2Click
41 end
42 object Button3: TButton
43 Left = 48
44 Top = 119
45 Width = 75
46 Height = 25
47 Caption = 'Button3'
48 TabOrder = 2
49 OnClick = Button3Click
50 end
51 object Button4: TButton
52 Left = 192
53 Top = 24
54 Width = 75
55 Height = 25
56 Caption = 'Button4'
57 TabOrder = 3
58 OnClick = Button4Click
59 end
60 object Button5: TButton
61 Left = 192
62 Top = 64
63 Width = 75
64 Height = 25
65 Caption = 'Button5'
66 TabOrder = 4
67 OnClick = Button5Click
68 end
69 end</pre>
</div>
 
-------Form 结束---------
 
 
 
 
 
--------------------------------------------其他--------------------------------------------
 
<img src="https://img2023.cnblogs.com/blog/811422/202301/811422-20230113143138793-671881149.png">
 
 
 
<div class="cnblogs_code">
<pre> 1 unit Unit1;
 2
 3 interface
 4
 5 uses
 6 Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
 7 Vcl.Controls, Vcl.Forms, Vcl.Dialogs, System.Generics.Collections, Generics.Defaults,
 8 Vcl.StdCtrls;
 9
10 type
11 TForm1 = class(TForm)
12 Button1: TButton;
13 Button2: TButton;
14 Memo1: TMemo;
15 procedure Button1Click(Sender: TObject);
16 procedure Button2Click(Sender: TObject);
17 private
18 { Private declarations }
19 public
20 { Public declarations }
21 end;
22 TMyDenerics<T>=class
23 private
24 FMyString:string;
25 FMyValue:T;
26 function GetMyValue: T;
27 procedure SetMyValue(const Value: T);
28 public
29 property Myvalue:T read GetMyValue write SetMyValue;
30 end;
31 var
32 Form1: TForm1;
33
34 implementation
35
36 {$R *.dfm}
37
38 procedure TForm1.Button1Click(Sender: TObject);
39 var
40 vMyGenerics:TMyDenerics<string>;
41 begin
42 vMyGenerics:=TMyDenerics<string>.Create;
43 vMyGenerics.FMyString:='aaaaaaaa';
44 vMyGenerics.Myvalue:='bbbb';
45 ShowMessage(vMyGenerics.Myvalue);
46 FreeAndNil(vMyGenerics);
47 end;
48
49 { TMyDenerics<T> }
50
51 function TMyDenerics<T>.GetMyValue: T;
52 begin
53 Result:=FMyValue;
54 end;
55
56 procedure TMyDenerics<T>.SetMyValue(const Value: T);
57 begin
58 FMyValue:= Value;
59 end;
60
61 procedure TForm1.Button2Click(Sender: TObject);
62 var
63 arr: TArray<Integer>;
64 num: Integer;
65 begin
66
67 SetLength(arr, 5);
68 arr[0] := 2;
69 arr[1] := 4;
70 arr[2] := 3;
71 arr[3] := 1;
72 arr[4] := 5;
73 TArray.Sort<Integer>(arr, TComparer<Integer>.Construct(
74 function (const a,b: Integer): Integer
75 begin
76 Result := b - a; //以小到大a-b、以大到小 b - a
77 end
78 ));
79 Memo1.Clear;
80 for num in arr do Memo1.Lines.Add(IntToStr(num)); //5 4 3 2 1
81 end;
82
83 end.</pre>
</div>
 
<div class="cnblogs_code">
<pre> 1 object Form1: TForm1
 2 Left = 0
 3 Top = 0
 4 BorderStyle = bsDialog
 5 Caption = 'Form1'
 6 ClientHeight = 213
 7 ClientWidth = 339
 8 Color = clBtnFace
 9 Font.Charset = DEFAULT_CHARSET
10 Font.Color = clWindowText
11 Font.Height = -11
12 Font.Name = 'Tahoma'
13 Font.Style = []
14 OldCreateOrder = False
15 PixelsPerInch = 96
16 TextHeight = 13
17 object Button1: TButton
18 Left = 232
19 Top = 32
20 Width = 75
21 Height = 25
22 Caption = 'Button1'
23 TabOrder = 0
24 OnClick = Button1Click
25 end
26 object Button2: TButton
27 Left = 232
28 Top = 95
29 Width = 75
30 Height = 25
31 Caption = 'Button2'
32 TabOrder = 1
33 OnClick = Button2Click
34 end
35 object Memo1: TMemo
36 Left = 24
37 Top = 8
38 Width = 185
39 Height = 161
40 Lines.Strings = (
41 'Memo1')
42 ScrollBars = ssBoth
43 TabOrder = 2
44 end
45 end</pre>
</div>
 
 
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来源：https://www.cnblogs.com/dmqhjp/p/15034422.html

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Delphi中的泛型