delphi - 在启动用户的默认 Web 浏览器时，如何阻止 Chromium 创建 "WebViewHost"主机窗口？

Question

我在 Delphi 6 应用程序中使用 Chromium Web 浏览器控件。

每当用户单击当前显示的网页中不在我的主网站上的 Web 链接时，我都会使用该 URL 启动他们的默认 Web 浏览器，方法是使用带有“的 Windows ShellExecute() 函数打开该 URL”打开'动词。我通过 BeforeBrowse() 事件处理程序执行此操作，同时取消导航。

换句话说，我不在 Chromium 控件中显示外部 URL，而是在用户的默认 Web 浏览器中显示它们。

它工作正常，但有时我也会弹出一个由我的应用程序拥有的独立窗口，它占据了大约一半的完全空白的屏幕(带有我的 Windows 主题的空白白色客户区域)。窗口的 Windows 类名称是“webviewhost”。

谁能告诉我如何抑制这个“幽灵”窗口？

Answer 1

这里的问题是弹出窗口。它们是在 OnBeforeBrowse 之前创建的事件被触发，您取消他们的导航，因此他们看起来像幽灵。

您可以通过设置OnBeforePopup的结果来阻止它们的创建事件为 True，但这将结束导航，因此 OnBeforeBrowse不会被解雇。如果您按照这种方式操作，那么您将必须执行 ShellExecute行动于 OnBeforePopup事件也是如此。

procedure TForm1.Chromium1BeforePopup(Sender: TObject;
  const parentBrowser: ICefBrowser; var popupFeatures: TCefPopupFeatures;
  var windowInfo: TCefWindowInfo; var url: ustring; var client: ICefBase;
  out Result: Boolean);
begin
  // you can set the Result to True here and block the window creation at all,
  // but then you will stop also the navigation and the OnBeforeBrowse event
  // won't be fired, so if you will follow this way then you'll have to perform
  // your ShellExecute action here as well

  if url <> 'http://www.yourdomain.com' then
  begin
    Result := True;
    ShellExecute(Handle, 'open', PChar(url), '', '', SW_SHOWNORMAL);
  end;
end;

另一种方法是设置 m_bWindowRenderingDisabled OnBeforePopup 中标记为 True事件应该阻止创建弹出窗口(如 ceflib.pas 中所述，而不是在官方文档中，恕我直言，窗口已创建但保持隐藏，我希望这不会导致任何泄漏，尚未验证) )并且导航将继续，因此 OnBeforePopup事件将被触发。

procedure TForm1.Chromium1BeforePopup(Sender: TObject;
  const parentBrowser: ICefBrowser; var popupFeatures: TCefPopupFeatures;
  var windowInfo: TCefWindowInfo; var url: ustring; var client: ICefBase;
  out Result: Boolean);
begin
  // you can set the m_bWindowRenderingDisabled flag to True here what should
  // prevent the popup window to be created and since we don't need to take
  // care about substitute parent for popup menus or dialog boxes of this popup
  // window (because we will cancel the navigation anyway) we don't need to set
  // the WndParent member here; but please check if there are no resource leaks
  // with this solution because it seems more that the window is just hidden

  if url <> 'http://www.yourdomain.com' then
    windowInfo.m_bWindowRenderingDisabled := True;
end;

以下代码是您的问题的模拟(以this tutorial为例，页面下部的链接my popup，如果您单击将打开弹出窗口)。

uses
  ShellAPI, ceflib, cefvcl;

const
  PageURL = 'http://www.htmlcodetutorial.com/linking/linking_famsupp_72.html';
  PopupURL = 'http://www.htmlcodetutorial.com/linking/popupbasic.html';

procedure TForm1.FormCreate(Sender: TObject);
begin
  Chromium1.Load(PageURL);
end;

procedure TForm1.Chromium1BeforeBrowse(Sender: TObject;
  const browser: ICefBrowser; const frame: ICefFrame;
  const request: ICefRequest; navType: TCefHandlerNavtype; isRedirect: Boolean;
  out Result: Boolean);
begin
  if request.Url = PopupURL then
  begin
    Result := True;
    ShellExecute(Handle, 'open', PChar(request.Url), '', '', SW_SHOWNORMAL);
  end;
end;

procedure TForm1.Chromium1BeforePopup(Sender: TObject;
  const parentBrowser: ICefBrowser; var popupFeatures: TCefPopupFeatures;
  var windowInfo: TCefWindowInfo; var url: ustring; var client: ICefBase;
  out Result: Boolean);
begin
{
  // Solution 1
  // this will block the popup window creation and cancel the navigation to
  // the target, so we have to perform the ShellExecute action here as well
  if url = PopupURL then
  begin
    Result := True;
    ShellExecute(Handle, 'open', PChar(url), '', '', SW_SHOWNORMAL);
  end;
}
{
  // Solution 2
  // or we can set the m_bWindowRenderingDisabled flag to True and the window
  // won't be created (as described in ceflib.pas), but the navigation continue
  if url = PopupURL then
    windowInfo.m_bWindowRenderingDisabled := True;
}
end;