unit3.pas

一个简单的图书管理系统

unit Unit3;

interface

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

type
  TForm3 = class(TForm)
    PageControl1: TPageControl;
    TabSheet1: TTabSheet;
    Button1: TButton;
    Label1: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    Button2: TButton;
    Label2: TLabel;
    TabSheet2: TTabSheet;
    Edit3: TEdit;
    Edit4: TEdit;
    Label3: TLabel;
    Label4: TLabel;
    Button3: TButton;
    Button4: TButton;
    Button5: TButton;
    ADODataSet1: TADODataSet;
    ADOCommand1: TADOCommand;
    ADODataSet2: TADODataSet;
    ADOCommand2: TADOCommand;
    procedure Button1Click(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure Button2Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure Edit1Change(Sender: TObject);
    procedure Edit2Change(Sender: TObject);
    procedure Edit4Change(Sender: TObject);
    procedure TabSheet2Exit(Sender: TObject);
    procedure TabSheet1Exit(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form3: TForm3;

implementation

{$R *.dfm}
uses unit1;

procedure TForm3.Button1Click(Sender: TObject);
begin
  close;
end;

procedure TForm3.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  Action := caFree;
  Form_show:=False;

end;

procedure TForm3.Button2Click(Sender: TObject);
begin
  if (Trim(edit1.Text)<>'') and (Trim(edit2.Text)<>'') then
      begin
        //打开数据库检测是否有重名
        Adodataset1.Active:=False;
        Adodataset1.CommandText:='select * from login where id ='''+trim(edit1.Text)+'''';
        Adodataset1.Active:=True;
        //没有同名ID,则写入数据库
        if Adodataset1.RecordCount=0 then
          begin
            adocommand1.CommandText:='insert into login values ('''+Trim(edit1.text)+''','''+Trim(edit2.Text)+''')';
            adocommand1.Execute;
            Messagedlg('操作成功！',mtinformation,[mbOK],0);
            //操作成功则还原成原始状态
            edit1.Text:='';
            edit2.Text:='';
            Button2.Enabled:=False;
            Adodataset1.Active:=False;
          end
        else
            Messagedlg('有相同登陆名！',mtwarning,[mbOK],0);
      end
      else
            Messagedlg('两项基本信息不能为空！',mtwarning,[mbOK],0);



end;

procedure TForm3.FormCreate(Sender: TObject);
begin
  button2.Enabled:=False;
  Form_show:=True;
end;

procedure TForm3.Edit1Change(Sender: TObject);
begin
  //当用户名和密码输入框改变是'写入数据库'才可用
  Button2.Enabled:=True;
end;

procedure TForm3.Edit2Change(Sender: TObject);
begin
   Button2.Enabled:=True;
end;

procedure TForm3.Edit4Change(Sender: TObject);
begin
  button3.Enabled:=True;
end;

procedure TForm3.TabSheet2Exit(Sender: TObject);
begin
  //离开时还原
  edit3.Text:='';
  edit4.Text:='';

  button3.Enabled:=False;
  button4.Enabled:=False;
  button5.Enabled:=False;
 
end;

procedure TForm3.TabSheet1Exit(Sender: TObject);
begin
  edit1.Text:='';
  edit2.Text:='';
  button2.Enabled:=False;
end;

procedure TForm3.Button3Click(Sender: TObject);
begin
  if Trim(Edit4.Text)<>'' then
     begin
       Adodataset2.Active:=False;
       Adodataset2.CommandText:='select * from login where id ='''+Trim(edit4.Text)+'''';
       Adodataset2.Active:=True;
       //showmessage(inttostr(adodataset2.RecordCount));
       //有符合条件的记录则显示
       if adodataset2.RecordCount= 1 then
         begin
           Edit3.Text:=Adodataset2.Fields[1].AsString;
           edit4.Enabled:=False;
           button4.Enabled:=True;
           button5.Enabled:=True;
           Adodataset2.Active:=False;
         end
      else
         messagedlg('没有此登陆名！',mtwarning,[mbOK],0);
     end
end;

procedure TForm3.Button5Click(Sender: TObject);
begin
  //删除当前登陆名对应记录
  Adocommand2.CommandText:='delete * from login where id ='''+trim(edit4.Text)+'''';
  Adocommand2.Execute;
  Messagedlg('操作成功！',mtinformation,[mbok],0);
  //操作完成还原
  edit3.Text:='';
  edit4.Text:='';
  edit4.Enabled:=True;
  button3.Enabled:=False;
  button4.Enabled:=False;
  button5.Enabled:=False;
 

end;

procedure TForm3.Button4Click(Sender: TObject);
begin
  if (messagedlg('你确实要修改吗？',mtwarning,[mbYes,mbNo],0)=mrYes) then
      begin
        if ((trim(edit4.Text)<>'') and (trim(edit3.Text)<>'')) then
          begin
             //重新写入数据库
             adocommand1.CommandText:='UPDATE login SET [password] = '''+Trim(edit3.Text)+''' WHERE id='''+Trim(edit4.Text)+'''';
             adocommand1.Execute;


             //操作完成还原
             edit3.Text:='';
             edit4.Text:='';
             edit4.Enabled:=True;

             button3.Enabled:=False;
             button4.Enabled:=False;
             button5.Enabled:=False;
            

          end
        else
          messagedlg('不能修改成空值!',mtwarning,[mbOK],0);
      end


end;

end.


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