querybalance.pas

餐饮管理源代码 使用BDE Administrator在本地机器上添加一个Paradox数据库别名命名为WorkData

unit queryBalance;

interface

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

type
  TfrmQueryBalance = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Label1: TLabel;
    memberId: TEdit;
    Label2: TLabel;
    balance: TEdit;
    Label3: TLabel;
    procedure FormCreate(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
    function isInteger(s:string):boolean;
  public
    { Public declarations }
  end;

var
  frmQueryBalance: TfrmQueryBalance;

implementation

uses dataModule,IdGlobal;

{$R *.dfm}

procedure TfrmQueryBalance.FormCreate(Sender: TObject);
begin
   dm:=Tdm.Create(self);
   activeControl:=memberId;
end;

procedure TfrmQueryBalance.FormClose(Sender: TObject;
  var Action: TCloseAction);
begin
   dm.Free;
end;

procedure TfrmQueryBalance.Button2Click(Sender: TObject);
begin
   {检查"会员编号"}
   if isInteger(memberId.Text)=false then
   begin
      messageDlg('会员编号不合法！',mtWarning,[mbOk],0);
      activeControl:=memberId;
      exit;
   end;
   {查询"结余"}
   with dm.tblMember do
   begin
      open;
      while not eof do
      begin
         {显示"结余"}
         if fieldByName('会员编号').AsString=memberId.Text then
         begin
            balance.Text:=fieldByName('结余').AsString;
            close;
            activeControl:=memberId;
            exit;
         end;
         next;
      end;
      close;
   end;
   {没有找到}
   messageDlg('没有找到相应的会员！',mtWarning,[mbOk],0);
   activeControl:=memberId;
end;

function TfrmQueryBalance.isInteger(s: string): boolean;
var
   i:integer;
begin
   i:=1;
   if length(s)=0 then
   begin
      result:=false;
      exit;
   end;
   while i<=length(s) do
   begin
      if (isNumeric(s[i])=false) then
      begin
         result:=false;
         exit;
      end;
      i:=i+1;
   end;
   result:=true;
end;

end.