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 程式師世界 >> 編程語言 >> 更多編程語言 >> Delphi >> Delphi 2009 泛型容器單元(Generics.Collections)[4]: TDictionary

Delphi 2009 泛型容器單元(Generics.Collections)[4]: TDictionary

編輯:Delphi

TDictionary 類似哈希表.

  本例效果圖:

Delphi 2009 泛型容器單元(Generics.Collections)[4]: TDictionary

  代碼文件:unit Unit1;
interface
uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs, StdCtrls;
type
 TForm1 = class(TForm)
  Memo1: TMemo;
  Edit1: TEdit;
  Edit2: TEdit;
  Button1: TButton;
  Button2: TButton;
  Button3: TButton;
  Button4: TButton;
  procedure FormCreate(Sender: TObject);
  procedure FormDestroy(Sender: TObject);
  procedure Button1Click(Sender: TObject);
  procedure Button2Click(Sender: TObject);
  procedure Button3Click(Sender: TObject);
  procedure Button4Click(Sender: TObject);
 end;
var
 Form1: TForm1;
implementation
{$R *.dfm}
uses Generics.Collections; {Delphi 2009 新增的泛型容器單元}
var
 Dictionary: TDictionary<Cardinal,string>; 
 {定義一個泛型 TDictionary 類, 指定有 Cardinal、string 構成}
{建立}
procedure TForm1.FormCreate(Sender: TObject);
begin
 Dictionary := TDictionary<Cardinal,string>.Create;
 Memo1.Clear;
 Button1.Caption := Button1.Caption + ' 添加';
 Button2.Caption := Button2.Caption + ' 刪除';
 Button3.Caption := Button3.Caption + ' 嘗試取值';
 Button4.Caption := Button4.Caption + ' 清空';
 Edit1.Clear;
 Edit2.Clear;
 Edit1.NumbersOnly := True;
end;
{釋放}
procedure TForm1.FormDestroy(Sender: TObject);
begin
 Dictionary.Free;
end;
{添加}
procedure TForm1.Button1Click(Sender: TObject);
var
 key: Cardinal;
 value: string;
 str: string;
 k,v: Boolean;
begin
 key := StrToIntDef(Edit1.Text, 0);
 value := Edit2.Text;
 if value = '' then value := 'Null';
 k := Dictionary.ContainsKey(key);   {Key 是否存在}
 v := Dictionary.ContainsValue(value); {Value 是否存在}
 
 if not k then
 begin
  Dictionary.Add(key, value);
  Memo1.Lines.Add(Format('%d=%s', [key, value])); {同步顯示}
 end;
 if k and not v then
 begin
  str := Format('key 已存在: %d=%s; 是否修改其值?', [key, Dictionary[key]]);
  if MessageBox(0, PChar(str), '提示', MB_OKCANCEL or MB_ICONQUESTION) = mrOk then
  begin
   //Dictionary[key] := value; {Dictionary[key] = Dictionary.Item[key]}
   Dictionary.AddOrSetValue(key, value);    {也可使用上一句}
   Memo1.Lines.Values[IntToStr(key)] := value; {同步顯示}
  end;
 end;
 if k and v then
 begin
  str := Format('%d=%s 已存在, 不能重復添加', [key, value]);
  MessageBox(0, PChar(str), '錯誤', MB_OK + MB_ICONHAND);
 end;
 Text := IntToStr(Dictionary.Count);
end;
{刪除: Remove}
procedure TForm1.Button2Click(Sender: TObject);
var
 key: Integer;
 i: Integer;
begin
 key := StrToIntDef(Edit1.Text, 0);
 if not Dictionary.ContainsKey(key) then 
 begin
  ShowMessageFmt('key: %d 不存在', [key]);
  Exit;
 end;
  
 Dictionary.Remove(key);
 Text := IntToStr(Dictionary.Count);
 
 {同步顯示}
 i := Memo1.Lines.IndexOfName(IntToStr(key));
 if i > -1 then Memo1.Lines.Delete(i);
end;
{嘗試取值: TryGetValue}
procedure TForm1.Button3Click(Sender: TObject);
var
 key: Integer;
 value: string;
begin
 key := StrToIntDef(Edit1.Text, 0);
 if Dictionary.TryGetValue(key, value) then
  ShowMessageFmt('key: %d 已存在, 其值是: %s', [key, value])
 else
  ShowMessageFmt('key: %d 不存在', [key])
end;
{清空: Clear}
procedure TForm1.Button4Click(Sender: TObject);
begin
 Dictionary.Clear;
 Text := IntToStr(Dictionary.Count);
 Memo1.Clear; {同步顯示}
end;
end.
窗體文件:object Form1: TForm1
 Left = 0
 Top = 0
 Caption = 'Form1'
 ClIEntHeight = 165
 ClIEntWidth = 275
 Color = clBtnFace
 Font.Charset = DEFAULT_CHARSET
 Font.Color = clWindowText
 Font.Height = -11
 Font.Name = 'Tahoma'
 Font.Style = []
 OldCreateOrder = False
 Position = poDesktopCenter
 OnCreate = FormCreate
 OnDestroy = FormDestroy
 PixelsPerInch = 96
 TextHeight = 13
 object Memo1: TMemo
  Left = 0
  Top = 0
  Width = 133
  Height = 165
  Align = alLeft
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -13
  Font.Name = 'CourIEr New'
  Font.Style = []
  Lines.Strings = (
   'Memo1')
  ParentFont = False
  ScrollBars = ssBoth
  TabOrder = 0
  ExplicitHeight = 176
 end
 object Button1: TButton
  Left = 139
  Top = 40
  Width = 128
  Height = 25
  Caption = 'Button1'
  TabOrder = 1
  OnClick = Button1Click
 end
 object Button2: TButton
  Left = 139
  Top = 71
  Width = 128
  Height = 25
  Caption = 'Button2'
  TabOrder = 2
  OnClick = Button2Click
 end
 object Button3: TButton
  Left = 139
  Top = 102
  Width = 128
  Height = 25
  Caption = 'Button3'
  TabOrder = 3
  OnClick = Button3Click
 end
 object Edit1: TEdit
  Left = 139
  Top = 8
  Width = 40
  Height = 21
  TabOrder = 4
  Text = 'Edit1'
 end
 object Edit2: TEdit
  Left = 185
  Top = 8
  Width = 81
  Height = 21
  TabOrder = 5
  Text = 'Edit2'
 end
 object Button4: TButton
  Left = 139
  Top = 133
  Width = 128
  Height = 25
  Caption = 'Button4'
  TabOrder = 6
  OnClick = Button4Click
 end
end


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