unit MainForm;

interface

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

type
  Tmain = class(TForm)
    MainMenu1: TMainMenu;
    N1: TMenuItem;
    N2: TMenuItem;
    N3: TMenuItem;
    N4: TMenuItem;
    N5: TMenuItem;
    N6: TMenuItem;
    N7: TMenuItem;
    N8: TMenuItem;
    N9: TMenuItem;
    N10: TMenuItem;
    N11: TMenuItem;
    StatusBar1: TStatusBar;
    procedure N2Click(Sender: TObject);
    procedure N3Click(Sender: TObject);
    procedure N4Click(Sender: TObject);
    procedure N6Click(Sender: TObject);
    procedure N7Click(Sender: TObject);
    procedure N8Click(Sender: TObject);
    procedure N10Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    function FindForm(caption: string): bool;
  end;

var
  main: Tmain;

implementation

{$R *.dfm}
uses ClassInfoForm,StudentInfoForm,CourseInfoForm,CourseElectForm,ScheduleForm,ScoreForm,PrintScoreForm;
//-----------通過用戶定義的函數，判斷窗體是否已存在--------------------
function TMain.FindForm(caption: string): bool;
var
i:integer;
begin
 for i:=0 to main.MDIChildCount do
  begin
   // 通過對窗體標題判斷窗體是否存在
    if main.MDIChildren[i].Caption=caption then
     begin
      //如果窗體已存在，則恢復窗體，并返回true
      SendMessage(mdichildren[i].Handle, WM_SYSCOMMAND, SC_RESTORE, 0);
      mdichildren[i].Enabled:=true;
      mdichildren[i].Show;
      mdichildren[i].SetFocus;
      result:=true;
      break;
     end
     else
     //如窗體不存在，則返回false，程序將創建窗體
      result:=false;
  end
end;

//--------------顯示【班級信息維護】窗體-------------------
procedure TMain.N2Click(Sender: TObject);
var
newform:TClassInfo;
begin
 if FindForm('班級信息維護')=false then
  newform:=TClassInfo.Create(application);
  newform.Caption:='班級信息維護';
end;

//--------------顯示【學生信息維護】窗體-------------------
procedure Tmain.N3Click(Sender: TObject);
var
newform:TStudentInfo;
begin
 if FindForm('學生信息維護')=false then
  newform:=TStudentInfo.Create(application);
  newform.Caption:='學生信息維護';
end;
//--------------顯示【課程信息維護】窗體-------------------
procedure Tmain.N4Click(Sender: TObject);
var
newform:TCourseInfo;
begin
 if FindForm('課程信息維護')=false then
  newform:=TCourseInfo.Create(application);
  newform.Caption:='課程信息維護';
end;
//--------------顯示【學生選課】窗體-------------------
procedure Tmain.N6Click(Sender: TObject);
var
newform:TCourseElect;
begin
 if FindForm('學生選課')=false then
  newform:=TCourseElect.Create(application);
  newform.Caption:='學生選課';
end;
//--------------顯示【課表查詢】窗體-------------------
procedure Tmain.N7Click(Sender: TObject);
var
newform:TSchedule;
begin
 if FindForm('課表查詢')=false then
  newform:=TSchedule.Create(application);
  newform.Caption:='課表查詢';
end;
//--------------顯示【成績輸入】窗體-------------------
procedure Tmain.N8Click(Sender: TObject);
var
newform:TScore;
begin
 if FindForm('成績輸入')=false then
  newform:=TScore.Create(application);
  newform.Caption:='成績輸入';
end;
//--------------顯示【打印成績單】窗體-------------------
procedure Tmain.N10Click(Sender: TObject);
var
newform:TPrintScore;
begin
 if FindForm('打印成績單')=false then
  newform:=TPrintScore.Create(application);
  newform.Caption:='打印成績單';
end;

end.