Question

综述

请参阅以下Craig和Sertac的有用评论。

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如以下最小化代码所示，TForm10设置为fsStayOnTop。 TForm10.btnTryDlgClick致电dlgOpen1.Execute，显示的对话框符合预期。但是，当我在TForm11.Create(Self).ShowModal内调用TForm10.btnTryFormClick时，表单隐藏在TForm10后面。我想知道如何理解这种行为，以及为什么标准的TOpenDialog可以按预期显示？任何评论都表示赞赏！

PS：一种解决方法是覆盖TForm11的CreateParams过程，并将Params.wndParent设置为0.但是在我看来，使用此变通方法将破坏窗口层次结构。

  procedure TForm11.CreateParams(var Params: TCreateParams); // override;
  begin
    inherited;
    params.wndParent := 0;
  end;

PS：Remy在以下相关的SO页面中提到了另一种解决方法：setting the modal Form's PopupParent property to be the StayOnTop Form。但在随后的评论中，Sertac提到这种解决方法也会破坏窗口层次结构。

PS：可能相关的SO页面：
Modal forms hidden by fsStayOnTop forms
How Can I Keep the FindDialog from Staying on Top (Delphi)?
How to make sure a dialog is always front of the main window
Form is hidden behind other forms when ShowModal is called
Make 2 forms able to overlap each other?
Multiple form Delphi applications and dialogs
Newly created modal window loses focus and become inacessible in Windows Vista
Delphi - How to prevent Forms/MsgBoxes to move under prior form?
How to allow Delphi secondary forms behind the main form
Fake modal dialog using Show?
Delphi MainFormOnTaskBar Modal windows bug

Unit10的来源：

    unit Unit10;

    interface

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

    type
      TForm10 = class(TForm)
        btnTryDlg: TButton;
        dlgOpen1: TOpenDialog;
        btnTryForm: TButton;
        procedure FormCreate(Sender: TObject);
        procedure btnTryDlgClick(Sender: TObject);
        procedure btnTryFormClick(Sender: TObject);
      end;

    var
      Form10: TForm10;

    implementation

    {$R *.dfm}

    uses
      Unit11;

    procedure TForm10.FormCreate(Sender: TObject);
    begin
      FormStyle := fsStayOnTop;
    end;

    procedure TForm10.btnTryDlgClick(Sender: TObject);
    begin
      dlgOpen1.Execute;
    //  dlgOpen1.Execute(Self.Handle);
    end;

    procedure TForm10.btnTryFormClick(Sender: TObject);
    begin
      TForm11.Create(Self).ShowModal;
    end;

    end.

Unit10的DFM：

    object Form10: TForm10
      Left = 0
      Top = 0
      Caption = 'Form10'
      ClientHeight = 255
      ClientWidth = 414
      Color = clBtnFace
      Font.Charset = DEFAULT_CHARSET
      Font.Color = clWindowText
      Font.Height = -11
      Font.Name = 'Tahoma'
      Font.Style = []
      OldCreateOrder = False
      OnCreate = FormCreate
      PixelsPerInch = 96
      TextHeight = 13
      object btnTryDlg: TButton
        Left = 32
        Top = 24
        Width = 153
        Height = 201
        Caption = 'Try dialog'
        TabOrder = 0
        OnClick = btnTryDlgClick
      end
      object btnTryForm: TButton
        Left = 224
        Top = 24
        Width = 153
        Height = 201
        Caption = 'btnTryForm'
        TabOrder = 1
        OnClick = btnTryFormClick
      end
      object dlgOpen1: TOpenDialog
        Left = 96
        Top = 168
      end
    end

Unit11的来源：

    unit Unit11;

    interface

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

    type
      TForm11 = class(TForm)
      end;


    implementation

    {$R *.dfm}

    end.

第11单元的DFM：

    object Form11: TForm11
      Left = 0
      Top = 0
      Caption = 'Form11'
      ClientHeight = 183
      ClientWidth = 203
      Color = clBtnFace
      Font.Charset = DEFAULT_CHARSET
      Font.Color = clWindowText
      Font.Height = -11
      Font.Name = 'Tahoma'
      Font.Style = []
      OldCreateOrder = False
      PixelsPerInch = 96
      TextHeight = 13
    end

Answer 1

设置模态窗体的PopupParent属性，与Remy建议的完全一样。这将使对话框的父对象成为StayOnTop表单，这是对话框的Execute方法已经在做的事情。我不确定Sertac的评论来自哪里，但使用PopupParent正确设置窗口层次结构，因此对话框将始终位于StayOnTop表格之上。

如何在其所有者表单上显示模式表单（其所有者设置为fsStayOnTop与否），就像TOpenDialog一样

1 个答案: