Visual Basic (Declaration) | |
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Public Sub StartFeedGetInformation( _ ByVal totalPages As Boolean, _ ByVal pageNumber As Integer _ ) |
Visual Basic (Usage) | Copy Code |
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C# | |
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public void StartFeedGetInformation( bool totalPages, int pageNumber ) |
Managed Extensions for C++ | |
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public: void StartFeedGetInformation( bool totalPages, int pageNumber ) |
C++/CLI | |
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public: void StartFeedGetInformation( bool totalPages, int pageNumber ) |
Parameters
- totalPages
- true to query the file for total number of pages, false otherwise.
- pageNumber
- 1-based index to the page number to query.
Visual Basic | Copy Code |
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RasterCodecs.FeedGetInformation |
C# | Copy Code |
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RasterCodecs.FeedGetInformation |
You must call the FeedGetInformation method to supply buffered data, and you must call StopFeedGetInformation when the process is complete.
This file information process is useful when receiving transmitted images, such as those on the Internet. It works the same way as the GetInformation method, except that your code supplies the image data. The file information process works as follows:
You call the StartFeedGetInformation method to initialize the file information process. You create a buffer, and each time you fill it with information, you call the FeedGetInformation method, which sends the data to the file information process just as if the data were being read from a file on disk.
If the FeedGetInformation returns true, this means the frameworks does not have enough data to get the information required; you must read more data and call the FeedGetInformation again. When FeedGetInformation returns false, the framework has gathered enough data and you can break out of the loop.
At any time after calling StartFeedGetInformation, you can call CancelFeedGetInformation to gracefully abort the feed operation. This allows you to end the feed process without throwing an exception. To end the file information process, you call the StopFeedGetInformation method, which cleans up the process, and returns an instance of the CodecsImageInfo class if successful. If you call this method before enough image data is passed to gather the information, it will successfully clean up the process, but will throw an exception. You should catch the exception if the process is canceled purposely.
This method cannot be used in combination with StartRedirecting.
Specifying true for totalPages can cause the process to be slow for files with large number of pages.
Target Platforms: Microsoft .NET Framework 2.0, Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family