delphi - 模态对话框不会将焦点返回到应用程序

Question

TPanel我有一个从named派生的自定义控件TTestCtrl。它拥有一个TImage32（来自 Graphics32）。

当用户双击图像时，我会显示一条消息。问题是我关闭消息后，焦点没有返回到主应用程序。因此，无论我在主应用程序/主窗体中单击什么，第一次单击都会丢失。

奇怪的事情：如果我Mesaj()不是从主窗体而是从主窗体调用该过程TTestCtrl，它就可以工作（第一次单击不再丢失）：

unit DerivedControl;

interface

uses
  System.SysUtils, System.Classes, Vcl.Controls, Vcl.ExtCtrls, Vcl.Dialogs, Vcl.Forms, GR32, GR32_Image;

type
  TTestCtrl = class(TPanel)
  private
    Img: TImage32;
  protected
    procedure ChromaDblClick(Sender: TObject);
  public
    constructor Create(AOwner: TComponent); override;
  published
  end;

procedure Mesaj(const MessageText, Title: string);

implementation

procedure Mesaj(const MessageText, Title: string);
begin
{$IFDEF MSWINDOWS}
   Application.MessageBox(PChar(MessageText), PChar(Title), 0)  { 'Title' will appear in window's caption }
{$ELSE}
   MessageDlg(MessageText, mtInformation, [mbOk], 0);
{$ENDIF}
end;

constructor TTestCtrl.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Width         := 200;
  Height        := 86;
  Img := TImage32.Create(Self);
  Img.Parent        := Self;
  Img.Align         := alClient;
  Img.OnDblClick    := ChromaDblClick;
end;

procedure TTestCtrl.ChromaDblClick(Sender: TObject);
begin
  Mesaj('Caption', 'From derived control');      // focus lost
end;

end.

---

下面的简单/最小应用程序是测试仪：

unit TesterForm;

interface

uses
  System.SysUtils, System.Classes, Vcl.StdCtrls, Vcl.Samples.Spin, Vcl.Controls, vcl.Forms, DerivedControl;

type
  TfrmTester = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
  public
  end;

var
  frmTester: TfrmTester;

implementation

{$R *.dfm}

var
  Ctrl: TTestCtrl;

procedure TfrmTester.FormCreate(Sender: TObject);
begin
  Ctrl := TTestCtrl.Create(Self);
  Ctrl.Parent := Self;
end;

procedure TfrmTester.Button1Click(Sender: TObject);
begin
  Mesaj('Caption', 'From main form');      // works
end;

end.

Answer 1

尝试这个 ：

procedure TTestCtrl.ChromaDblClick(Sender: TObject);
var F : TcustomForm;
begin
  Mesaj('Caption', 'From derived control');      // focus lost
  F := GetParentForm(Self);
  if Assigned(F) then F.BringToFront;

end;