代替showmodal其他两种方法和showmodal各有什么优缺点？

Henry.6 2013-02-16 04:47:14

代替showmodal其他两种方法



procedure TForm1.Button1Click(Sender: TObject);

begin

enablewindow(handle,false);//窗口一不可用

form2.show;



end;

procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction);

begin

enablewindow(form1.handle,true);//可用

end;

或



var

  Form1: TForm1;

  WindowList: Pointer;





implementation



uses Unit2;



{$R *.DFM}



procedure TForm1.Button1Click(Sender: TObject);

begin

  WindowList:= DisableTaskWindows(self.handle);

  form2.show;



end;



uses Unit1;



{$R *.DFM}



procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction);

begin

     EnableTaskWindows(unit1.WindowList);

end;

...全文

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Henry.6 2013-02-27

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引用 10 楼 sololie 的回复:

引用 6 楼 6rl 的回复:引用 5 楼 yct0605 的回复:showmodal窗体时，主窗体里面创建的线程是可以继续进行的在什么场景下会考虑用enablewindow那两种方法代替showModal? 答好给多分没必要用enablewindow，这个是api函数，showmodal是vcl函数，里面就是调用了eanablewindow。你只需要考虑……

原来EnableTaskWindow里就包装了EnableWindow。

sololie 2013-02-26

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引用 6 楼 6rl 的回复:

引用 5 楼 yct0605 的回复:showmodal窗体时，主窗体里面创建的线程是可以继续进行的在什么场景下会考虑用enablewindow那两种方法代替showModal? 答好给多分

没必要用enablewindow，这个是api函数，showmodal是vcl函数，里面就是调用了eanablewindow。你只需要考虑什么场景用show或showmodal，后者模态窗口，占据在该进程中所有窗口的顶层，模态窗口提示用户介入，当返回后自动销毁窗口。


// ShowModal 源码
function TCustomForm.ShowModal: Integer;
var
  WindowList: TTaskWindowList;
  LSaveFocusState: TFocusState;
  SaveCursor: TCursor;
  SaveCount: Integer;
  ActiveWindow: HWnd;
begin
  CancelDrag;
  if Visible or not Enabled or (fsModal in FFormState) or
    (FormStyle = fsMDIChild) then
    raise EInvalidOperation.Create(SCannotShowModal);
  if GetCapture <> 0 then SendMessage(GetCapture, WM_CANCELMODE, 0, 0);
  ReleaseCapture;
  Application.ModalStarted;
  try
    { RecreateWnd could change the active window }
    ActiveWindow := GetActiveWindow;
    Include(FFormState, fsModal);
    if (PopupMode = pmNone) and (Application.ModalPopupMode <> pmNone) then
    begin
      RecreateWnd;
      HandleNeeded;
      { The active window might have become invalid, refresh it }
      if (ActiveWindow = 0) or not IsWindow(ActiveWindow) then
        ActiveWindow := GetActiveWindow;
    end;
    LSaveFocusState := SaveFocusState;
    Screen.SaveFocusedList.Insert(0, Screen.FocusedForm);
    Screen.FocusedForm := Self;
    SaveCursor := Screen.Cursor;
    Screen.Cursor := crDefault;
    SaveCount := Screen.CursorCount;
    WindowList := DisableTaskWindows(0);
    try
      Show;
      try
        SendMessage(Handle, CM_ACTIVATE, 0, 0);
        ModalResult := 0;
        repeat
          Application.HandleMessage;
          if Application.Terminated then ModalResult := mrCancel else
            if ModalResult <> 0 then CloseModal;
        until ModalResult <> 0;
        Result := ModalResult;
        SendMessage(Handle, CM_DEACTIVATE, 0, 0);
        if GetActiveWindow <> Handle then ActiveWindow := 0;
      finally
        Hide;
      end;
    finally
      if Screen.CursorCount = SaveCount then
        Screen.Cursor := SaveCursor
      else Screen.Cursor := crDefault;
      EnableTaskWindows(WindowList);
      if Screen.SaveFocusedList.Count > 0 then
      begin
        Screen.FocusedForm := TCustomForm(Screen.SaveFocusedList.First);
        Screen.SaveFocusedList.Remove(Screen.FocusedForm);
      end else Screen.FocusedForm := nil;
      { ActiveWindow might have been destroyed and using it as active window will
        force Windows to activate another application }
      if (ActiveWindow <> 0) and not IsWindow(ActiveWindow) then
        ActiveWindow := FindTopMostWindow(0);
      if ActiveWindow <> 0 then
        SetActiveWindow(ActiveWindow);
      RestoreFocusState(LSaveFocusState);
      Exclude(FFormState, fsModal);
    end;
  finally
    Application.ModalFinished;
  end;
end;