unit1.pas

本光盘是《Delphi 7应用教程》一书的配套光盘

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Memo1: TMemo;
    Label1: TLabel;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    OpenDialog1: TOpenDialog;
    Button4: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation
   var
     F1: TextFile;//定义一个文本文件变量
{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
   OpenDialog1.Execute ;//弹出打开对话框
   edit1.Text :=OpenDialog1.FileName; //显示要打开的文件名
end;

procedure TForm1.Button2Click(Sender: TObject);//打开文件并把文件内容显示在Memo1中
var
  Line:string;
begin
  If length(Edit1.Text)<>0 then //输入了文件名
     begin
         AssignFile(F1,Edit1.Text );
         Reset(F1);
         Memo1.Lines.Clear ;
         while not eof(F1)  do //不是文件的结尾
            Begin
               readln(F1,line); //读取一行
               Memo1.Lines.Add(Line);//把该行显示在Memo1中
            end;
     end
     else
        ShowMessage('必须输入文件名');

end;

procedure TForm1.Button3Click(Sender: TObject);
Var
  i:integer;
begin
  if Memo1.Modified   then //如果Memo1中的内容已经修改
      begin
          Rewrite(f1); //创建打开文件
          for i:=0 to Memo1.Lines.Count -1 do //把Memo1中的内容写到文件中去
                Writeln(f1,Memo1.lines[i]);
      end;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
  CloseFile(f1);Application.Terminate;  //关闭文件
end;

end.