C # acrobat opened PDF error, prompting Acrobat.acropddocclass not to cast to Acrobat.cacropddoc, using COM component { 9b4cd3e7-4981-101b-9ca8-9240ce2738ae},hresult:0x80004002

To convert the contents of a PDF file to a picture in bulk, two questions were encountered during the writing process.

One, download the SDK, prompt to reference COM component Acrobat, but on my computer is not visible, only see Adobe Acrobat 7.0 browswer Control Type Library 1.0.

My computer, Acrobat XI and Acrobat Reader DC, were all loaded, and I didn't find a lap.

Later, a lower version of the Acrobat DC installer was installed, which can be seen in the COM component after installation.

The reason is that the previously installed Acrobat Xi is a green cracked version, eliminating a lot of installation steps, may not be installed during the registration of COM components caused .

Second, after the reference, in Avdoc.open this place always error, download the SDK is also, hint Acrobat.acropddocclass cannot cast to Acrobat.cacropddoc, use COM component { 9b4cd3e7-4981-101b-9ca8-9240ce2738ae},hresult:0x80004002

This mistake, also looked for a long time, have no result, the official also some people ask https://forums.adobe.com/thread/301879, but there is no solution.

Later I changed a computer, reinstall Acrobat DC, test the program, found no problem, can open the pdf file directly.

The other computer is clean, did not install any version of Acrobat, this thought may be installed in the two version of the conflict caused , so the software uninstall, only installed Acrobat DC, the result is not.

Had to again uninstall Acrobat DC, while searching for Acrobat in the registration table, the search to all deleted, then install Acrobat DC, run the program, found to open, normal execution.

C # acrobat opened PDF error, prompting Acrobat.acropddocclass not to cast to Acrobat.cacropddoc, using COM component { 9b4cd3e7-4981-101b-9ca8-9240ce2738ae},hresult:0x80004002