creditoolunit.pas

一个功能完美的学生成绩管理系统 使用ACCESS数据库在DATA文件夹中 功能强大

unit crediToolUnit;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls, Buttons, Grids, DBGrids;

type
  TCreditToolForm = class(TForm)
    Panel1: TPanel;
    Panel2: TPanel;
    Label1: TLabel;
    Edit1: TEdit;
    Panel3: TPanel;
    ComboBox1: TComboBox;
    Label2: TLabel;
    Label3: TLabel;
    Edit2: TEdit;
    Label4: TLabel;
    Edit3: TEdit;
    DBGrid1: TDBGrid;
    BitBtn1: TBitBtn;
    BitBtn2: TBitBtn;
    procedure FormCreate(Sender: TObject);
    procedure BitBtn1Click(Sender: TObject);
    procedure BitBtn2Click(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);

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

var
  CreditToolForm: TCreditToolForm;

implementation
uses datamoduleunit;

{$R *.dfm}

procedure TCreditToolForm.FormCreate(Sender: TObject);
begin
with datamodule1.tabletype do
 begin
   open;
   while not eof do
      begin
      combobox1.Items.Add(fieldbyname('TypeName').AsString);
      next;
      end;
   close;
 end;

with datamodule1.queryall do
   begin
     close;
     SQL.Clear;
     sql.Add('select sno,course.cname,credit,grade from grade,course,coursetype ');
     sql.Add('where course.cname=grade.cname and');
     sql.Add('course.typeno=coursetype.typeno and');
     sql.Add('sno=:sno and');
     sql.Add('typename=:typename'); 
   end;
end;

procedure TCreditToolForm.BitBtn1Click(Sender: TObject);
var pass,notpass:real;
begin
pass:=0;
notpass:=0;
if (edit1.Text='') or  (combobox1.Text='') then
  begin
    messagebox (handle,'条件不能为空，请输入！','警告',mb_ok) ;
    exit;
  end;
with datamodule1.queryall do
   begin
     close;
     Parameters.ParamByName('sno').Value:=edit1.Text;
     Parameters.ParamByName('typename').Value:=combobox1.Text;
     prepared;
     open;
     while not eof do
       begin
         if not datamodule1.passed(fieldbyname('grade').AsString) then
         notpass:=notpass+fieldbyname('credit').AsFloat
         else
           pass:=pass+ fieldbyname('credit').AsFloat;
         next;
       end;
   end;
panel3.Visible:=true;
edit2.Text:=floattostr(pass);
edit3.Text:=floattostr(notpass);
end;

procedure TCreditToolForm.BitBtn2Click(Sender: TObject);
begin
panel3.Visible:=false;
edit1.Text:='';
combobox1.ItemIndex:=-1;
datamodule1.queryall.Close;
end;

procedure TCreditToolForm.FormClose(Sender: TObject;
  var Action: TCloseAction);
begin
datamodule1.queryall.Close;
end;

end.