delphi - 如何在其所有者表单之上显示模态表单(其所有者是否设置为 fsStayOnTop)，就像 TOpenDialog 一样

Question

总结:

请参阅下面来自 Craig 和 Sertac 的有用评论。

================================================== =======

如下面的最小化代码所示，TForm10 设置为 fsStayOnTop。 TForm10.btnTryDlgClick 调用 dlgOpen1.Execute，显示的对话框符合预期。但是，当我在 TForm10.btnTryFormClick 内调用 TForm11.Create(Self).ShowModal 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 TOpenDialog 可以按预期显示？如有任何评论，我们将不胜感激!

PS:一种解决方法是重写 TForm11 的 CreateParams 过程，并将 Params.wndParent 设置为 0。但在我看来，使用此解决方法会破坏窗口层次结构。

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

PS:Remy 在下面的相关 SO 页面中提到了另一种解决方法:将模态表单的 PopupParent 属性设置为 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

第 10 单元来源:

    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

第 11 单元来源:

    unit Unit11;

    interface

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

    type
      TForm11 = class(TForm)
      end;


    implementation

    {$R *.dfm}

    end.

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

设置模态表单的 PopupParent 属性，就像 Remy 建议的那样。这将使对话框成为 StayOnTop 窗体的父级，这就是对话框的 Execute 方法已经执行的操作。我不确定 Sertac 的注释来自哪里，但使用 PopupParent 可以正确设置窗口层次结构，因此对话框将始终位于 StayOnTop 表单上方。