delphi - 将变量传递给另一个表单

Question

我得到了带有一些变量的 Form1，我想将其传递给另一个 Form3，我将在其中使用它。所以我有两个问题。

• 如何以另一种形式访问该变量？我想会的类似于

  var newIdList:= Form1.idList
  

• 当 var idList 获取值时

    procedure TForm1.Button1Click(Sender: TObject);begin
    idList:=strtoint(edit1.text);
    end
  

  并且我在另一个表单中显示了新表单，我仍然可以在 idList 中获取值吗？

  procedure TForm1.Button2Click(Sender: TObject); 
  begin
  form1.hide;
  form3.show;
  end
  

<小时/>

    unit Unit1;
    
    interface
    
    uses
      Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
      Dialogs, StdCtrls, ComCtrls;
    
    type
      TForm1 = class(TForm)
        PageControl1: TPageControl;
        TabSheet1: TTabSheet;
        TabSheet2: TTabSheet;
        TabSheet3: TTabSheet;
        Label5: TLabel;
        Edit3: TEdit;
        Edit2: TEdit;
        Button3: TButton;
        Edit4: TEdit;
        Button2: TButton;
        Button1: TButton;
        Edit1: TEdit;
        Label1: TLabel;
        Label3: TLabel;
        Label2: TLabel;
        Edit5: TEdit;
        Label7: TLabel;
        Label6: TLabel;
        Button4: TButton;
        ListBox1: TListBox;
        procedure FormCreate(Sender: TObject);
        procedure Button1Click(Sender: TObject);
        procedure Button2Click(Sender: TObject);
        procedure Edit4Click(Sender: TObject);
        procedure Button3Click(Sender: TObject);
        procedure Edit1Click(Sender: TObject);
        procedure Button4Click(Sender: TObject);
    
      private
        { Private declarations }
      public
        { Public declarations }
        idList,imieList,nazwiskoList,adresList: TStringList;
      end;
    
    var
      Form1: TForm1;
      plik:TStringList;
      tempPlik:TextFile;
      st:string;
      linia_klient,linia_video:array[0..20] of string;
      id:integer;
    
    implementation
    
    uses Unit3;
    
    {$R *.dfm}
    
    .
    .
    .
    
    procedure TForm1.FormCreate(Sender: TObject);
    var i:integer;
    begin
    Edit1.Text:='Witaj, Podaj ID klienta';
    Label1.Caption:='ID Klienta';
    idList:=TStringList.Create;
    imieList:=TStringList.Create;
    nazwiskoList:=TStringList.Create;
    adresList:=TStringList.Create;
    
    if (FileExists('idList.txt')=true) then idList.LoadFromFile('idList.txt') else idList.SaveToFile('idList.txt');
    if (FileExists('imieList.txt')=true) then imieList.LoadFromFile('imieList.txt') else imieList.SaveToFile('imieList.txt');
    if (FileExists('nazwiskoList.txt')=true) then nazwiskoList.LoadFromFile('nazwiskoList.txt') else nazwiskoList.SaveToFile('nazwiskoList.txt');
    if (FileExists('adresList.txt')=true) then adresList.LoadFromFile('adresList.txt') else adresList.SaveToFile('adresList.txt');
    
    AssignFile(tempPlik,'video.txt');
    Reset(tempPlik);
    i:=0;
    While Not Eof(tempPlik) do
      begin
        Readln(tempPlik,linia_video[i]);
        inc(i);
      end;
    
    CloseFile(tempPlik);
    end;
    
    
    
    procedure TForm1.Button4Click(Sender: TObject);
    begin
      //Form1.Hide;
      Form3.Show;
    end;
    
    end.



unit Unit3;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm3 = class(TForm)
    Button1: TButton;
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    procedure Button1Click(Sender: TObject);
    procedure FormShow(Sender: TObject);


  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form3: TForm3;

implementation

uses Unit1;

{$R *.dfm}

procedure TForm3.Button1Click(Sender: TObject);
begin
Form3.Hide;
//Form1.Show;
end;



procedure TForm3.FormShow(Sender: TObject);
begin

Label4.Caption:= intToStr(idList.Count);
end;

end.

Answer 1

(我假设每个表单都驻留在其自己的单元中。)首先，您必须确保其他单元可以访问 idList。例如，

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;

type
  TForm1 = class(TForm)
  private
    { Private declarations }
    idList: integer;
  public
    { Public declarations }
  end;

不会，但是

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;

type
  TForm1 = class(TForm)
  private
    { Private declarations }
  public
    { Public declarations }
    idList: integer;
  end;

没问题。在这种情况下，您在 Unit2 中所需要做的就是将 Unit1 添加到其“使用列表”(按 Alt+F11，或使用 File/'Use Unit.. .'，在 Unit2 中或编辑 Form2 时)。然后，您可以使用 Form1.idList 访问 Unit2 内任何位置的变量。 (Form1是Unit1中TForm1的全局实例变量)。

例如，

unit Unit2;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm2 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form2: TForm2;

implementation

uses Unit1;     // <-- Add manually, or press Alt+F11 (or use File/'Use Unit...')

{$R *.dfm}

procedure TForm2.Button1Click(Sender: TObject);
begin
  ShowMessage(IntToStr(Form1.idList));
end;

end.