Creating and Using URL Monikers与IDOWNLOADMANAGER::DOWNLOAD

只是学习过程中的记录，不是技术文章，大家要学技术的就不要往下看了，以免耽误你的时间，如果你还能给我点指引，那就更好了。

在研究如何再webbrowser中实现自定义下载的文章中，很多都提到需要通过RegisterBindStatusCallback 来获取下载文件名，又提到通过URL Monikers获取，可我看URL Monikers的介绍：（http://msdn.microsoft.com/en-us/library/aa741006(v=vs.85).aspx）

Creating a URL Moniker

Follow these steps to create a URL moniker for an application:

1. Optional, but recommended. Implement the IBindStatusCallback interface.
2. Optional, but recommended. Create an instance of your IBindStatusCallback interface.
3. Call CreateURLMoniker with the URL and get the IMoniker interface.
4. Call CreateAsyncBindCtx and get the IBindCtx interface.
5. If IBindStatusCallback has been implemented, call RegisterBindStatusCallback with the IBindCtx and IBindStatusCallback interfaces.
6. Call one of the IMoniker binding methods (either IMoniker::BindToStorage or IMoniker::BindToObject) with the IBindCtx interface. In the asynchronous case (where IBindStatusCallback has been implemented), the client application can get a pointer to theIStream orIStorage interface. The client application should call the IUnknown::Release method on the interface and use the interface returned in theIBindStatusCallback::OnDataAvailable call.

7. If IBindStatusCallback has been implemented, the IBindStatusCallback::GetBindInfo method is called by the IMoniker binding method to get the bind information.

   Warning   The size of the BINDINFO structure used by IBindStatusCallback::GetBindInfo has changed in Microsoft Internet Explorer 4.0 and later. Developers must write code that checks the size of theBINDINFO structure that is passed into their implementation of theIBindStatusCallback::GetBindInfo method before writing to members of the structure. For more information, see theHandling BINDINFO Structures section.

8. If IBindStatusCallback has been implemented, the IBindStatusCallback::OnStartBinding method will be called.
9. If IBindStatusCallback has been implemented, the IBindStatusCallback::OnProgress method will be called.
10. If IBindStatusCallback has been implemented, either IBindStatusCallback::OnDataAvailable (if IMoniker::BindToStorage was used) or IBindStatusCallback::OnObjectAvailable (if IMoniker::BindToObject was used) will be called.
11. If IBindStatusCallback has been implemented, steps 9 and 10 are repeated until the binding is completed.
12. If IBindStatusCallback has been implemented, the IBindStatusCallback::OnStopBinding method will be called.

而在 IDOWNLOADMANAGER::DOWNLOAD中也说到：（http://msdn.microsoft.com/en-us/library/aa753612(v=vs.85).aspx）

Parameters

pmk               [in] A pointer to an IMoniker interface that specifies the object to be downloaded. pbc                [in] A pointer to an IBindCtx interface that specifies information used by the moniker in the bind process. dwBindVerb  [in] A value of type DWORD that specifies the action to be performed during the bind process. grfBINDF       [in] A value of type LONG that specifies a combination of values taken from the BINDF enumeration indicating how the bind process is handled. pBindInfo      [in] A pointer to a variable of type BINDINFO that specifies the client application's requirements for binding. pszHeaders  [in] A value of type LPCOLESTR that specifies additional headers to use with IHttpNegotiate. pszRedir       [in] A value of type LPCOLESTR that specifies the URL that the moniker is redirected to. uiCP             [in] A value of type UINT that specifies the code page of the object's display name.

其实，如果实现了IDOWNLOADMANAGER，与 URL Monikers的前4个步骤区别就只差 IBindStatusCallback interface了.不知从 pBindInfo 是否能获得 IBindStatusCallback interface呢？

多谢 蒋晟 提供的代码参考，真的十分感谢 蒋晟 ，离实现自定义下载越来越近了。

RegisterBindStatusCallback return E_FAIL 参见： http://msdn.microsoft.com/en-us/library/aa753618(v=vs.85).aspx

其中说到了关于：_BSCB_Holder_

如果是没有跳转的下载，则在第一次进行RegisterBindStatusCallback就OK了，如果是有跳转的下载，则第一次会返回E_FAIL ，需要按上文说的进行RevokeObjectParam，然后重新进行 RegisterBindStatusCallback。

2014.3.19：哈哈，终于见到要下载的文件名了（可不是普通的下载哦，是有跳转链接的下载哦）。

2014.3.19 15：00 噢耶，搞定。