我正在使用 Systems.Windows.Forms.Webbrowser
控件,需要覆盖下载管理器。我已经按照 这里 的说明子类化了表单并覆盖了 CreateWebBrowserSiteBase()
方法。
/// <summary>
/// Browser with download manager
/// </summary>
public class MyBrowser : WebBrowser
{
/// <summary>
/// Returns a reference to the unmanaged WebBrowser ActiveX control site,
/// which you can extend to customize the managed <see ref="T:System.Windows.Forms.WebBrowser"/> control.
/// </summary>
/// <returns>
/// A <see cref="T:System.Windows.Forms.WebBrowser.WebBrowserSite"/> that represents the WebBrowser ActiveX control site.
/// </returns>
protected override WebBrowserSiteBase CreateWebBrowserSiteBase()
{
var manager = new DownloadWebBrowserSite(this);
manager.FileDownloading += (sender, args) =>
{
if (FileDownloading != null)
{
FileDownloading(this, args);
}
};
return manager;
}
}
在
DownloadWebBrowserSite
中,我实现了 IServiceProvider
来在请求时提供一个 IDownloadManager
。 /// <summary>
/// Queries for a service
/// </summary>
/// <param name="guidService">the service GUID</param>
/// <param name="riid"></param>
/// <param name="ppvObject"></param>
/// <returns></returns>
public int QueryService(ref Guid guidService, ref Guid riid, out IntPtr ppvObject)
{
if ( (guidService == Constants.IID_IDownloadManager && riid == Constants.IID_IDownloadManager ))
{
ppvObject = Marshal.GetComInterfaceForObject(_manager, typeof(IDownloadManager));
return Constants.S_OK;
}
ppvObject = IntPtr.Zero;
return Constants.E_NOINTERFACE;
}
DownloadManager
是从上面的示例中提取的。/// <summary>
/// Intercepts downloads of files, to add as PDFs or suppliments
/// </summary>
[ComVisible(true)]
[Guid("bdb9c34c-d0ca-448e-b497-8de62e709744")]
[CLSCompliant(false)]
public class DownloadManager : IDownloadManager
{
/// <summary>
/// event called when the browser is about to download a file
/// </summary>
public event EventHandler<FileDownloadEventArgs> FileDownloading;
/// <summary>
/// Return S_OK (0) so that IE will stop to download the file itself.
/// Else the default download user interface is used.
/// </summary>
public int Download(IMoniker pmk, IBindCtx pbc, uint dwBindVerb, int grfBINDF, IntPtr pBindInfo,
string pszHeaders, string pszRedir, uint uiCP)
{
// Get the display name of the pointer to an IMoniker interface that specifies the object to be downloaded.
string name;
pmk.GetDisplayName(pbc, null, out name);
if (!string.IsNullOrEmpty(name))
{
Uri url;
if (Uri.TryCreate(name, UriKind.Absolute, out url))
{
if ( FileDownloading != null )
{
FileDownloading(this, new FileDownloadEventArgs(url));
}
return Constants.S_OK;
}
}
return 1;
}
}
问题在于
pmk.GetDisplayName
返回的是初始URL,而不是要下载的项目的URL。如果URI指向动态页面,例如http://www.example.com/download.php,我将无法获取实际要下载的文件。我需要从标头中获取URL,以便获取我应该下载的实际文件。谷歌表明我必须创建一个实现
IBindStatusCallback
,同时还实现IHttpNegotiate
和IServiceProvider
以响应IID_IHttpNegotiate
,以便我可以看到IHttpNegotiate.OnResponse
。我已经成功实现了这一点,但是QueryService
似乎只会请求IID_IInternetProtocol
而永远不会请求IID_IHttpNegotiate
。任何建议都将非常有用。
IBindStatusCallback
。我已经编辑了问题。我已经实现了 msdn.microsoft.com/en-us/library/ms775054(v=vs.85).aspx 建议的内容。问题在于IBindStatusCallback
的QueryService
从未调用IID_IHttpNegotiate
(以便我可以返回IHttpNegotiate
实现)。它总是调用IID_IInternetProtocol
。当QueryService
要求IID_IInternetProtocol
时,我不知道该返回什么。 - jimbojones