一个 MDI子窗口，在运行 MDI 父窗口时，MDI子窗口自动运行，怎样在点击菜单项时才让它运行。(20分)

以下是代码：

unit MAIN;

interface

uses Windows, SysUtils, Classes, Graphics, Forms, Controls, Menus,
StdCtrls, Dialogs, Buttons, Messages, ExtCtrls, ComCtrls, StdActns,
ActnList, ToolWin, ImgList;

type
TMainForm = class(TForm)
MainMenu1: TMainMenu;
File1: TMenuItem;
FileNewItem: TMenuItem;
FileOpenItem: TMenuItem;
FileCloseItem: TMenuItem;
Window1: TMenuItem;
Help1: TMenuItem;
N1: TMenuItem;
FileExitItem: TMenuItem;
WindowCascadeItem: TMenuItem;
WindowTileItem: TMenuItem;
WindowArrangeItem: TMenuItem;
HelpAboutItem: TMenuItem;
OpenDialog: TOpenDialog;
FileSaveItem: TMenuItem;
FileSaveAsItem: TMenuItem;
Edit1: TMenuItem;
CutItem: TMenuItem;
CopyItem: TMenuItem;
PasteItem: TMenuItem;
WindowMinimizeItem: TMenuItem;
StatusBar: TStatusBar;
ActionList1: TActionList;
EditCut1: TEditCut;
EditCopy1: TEditCopy;
EditPaste1: TEditPaste;
FileNew1: TAction;
FileSave1: TAction;
FileExit1: TAction;
FileOpen1: TAction;
FileSaveAs1: TAction;
WindowCascade1: TWindowCascade;
WindowTileHorizontal1: TWindowTileHorizontal;
WindowArrangeAll1: TWindowArrange;
WindowMinimizeAll1: TWindowMinimizeAll;
HelpAbout1: TAction;
FileClose1: TWindowClose;
WindowTileVertical1: TWindowTileVertical;
WindowTileItem2: TMenuItem;
ToolBar2: TToolBar;
ToolButton1: TToolButton;
ToolButton2: TToolButton;
ToolButton3: TToolButton;
ToolButton4: TToolButton;
ToolButton5: TToolButton;
ToolButton6: TToolButton;
ToolButton9: TToolButton;
ToolButton7: TToolButton;
ToolButton8: TToolButton;
ToolButton10: TToolButton;
ToolButton11: TToolButton;
ImageList1: TImageList;
N2: TMenuItem;
procedure FileNew1Execute(Sender: TObject);
procedure FileOpen1Execute(Sender: TObject);
procedure HelpAbout1Execute(Sender: TObject);
procedure FileExit1Execute(Sender: TObject);
procedure N2Click(Sender: TObject);
private
{ Private declarations }
procedure CreateMDIChild(const Name: string);
public
{ Public declarations }
end;

var
MainForm: TMainForm;

implementation

{$R *.dfm}

uses CHILDWIN, about, Unit1;

procedure TMainForm.CreateMDIChild(const Name: string);
var
Child: TMDIChild;
begin
{ create a new MDI child window }
Child := TMDIChild.Create(Application);
Child.Caption := Name;
if FileExists(Name) then Child.Memo1.Lines.LoadFromFile(Name);
end;

procedure TMainForm.FileNew1Execute(Sender: TObject);
begin
CreateMDIChild('NONAME' + IntToStr(MDIChildCount + 1));
end;

procedure TMainForm.FileOpen1Execute(Sender: TObject);
begin
if OpenDialog.Execute then
CreateMDIChild(OpenDialog.FileName);
end;

procedure TMainForm.HelpAbout1Execute(Sender: TObject);
begin
AboutBox.ShowModal;
end;

procedure TMainForm.FileExit1Execute(Sender: TObject);
begin
Close;
end;

procedure TMainForm.N2Click(Sender: TObject);
begin
form1.showmodal; // 此处可行吗？
end;

end.

子窗口不能用ShowModal,会出错，可以控制表单的Visible属性，使用Show可以．

一开始的那个

TO :薛獅
SHOW也不行
TO : yxjdelphi
"一开始的那个" 是什么意思?

打开菜单Project,选其中的Options,打开对话框切换到Forms,把子窗体Form1从
Auto-create forms移到Available forms便可

我的form1是已有的，不是动态建立的

让你子窗体的Visible为False;然后用Show。

在工程的Options-->Forms中将MDI子窗体设置成Available forms，然后在主窗体中创建子窗体：
procedure TMainFrm.BitBtn1Click(Sender: TObject);
begin
with TMDIChildFrm.Create(Application) do
begin
Show;
end;
end;

接受答案了.