How to create C++ Custom 'promise' from WinRT to use in javascript

Question

I'd like to implement custom promise objects using custom WinRT\C++ code (just like 'StorageFile.RenameAsync()' and many other Async method do). From the documentation it looks these objects need to implement IAsyncAction\IAsyncInfo but I havent found any C++ samples depicting the exact flow and usage of these interfaces. 

 

Is there a sample or some reference documentation on how to expose custom WinRT objects (using IAsyncAction\IAsyncInfo) to JavaScript as 'promises'?

Answer 1

I am not aware of any C++ samples.  Here is a C# implementation you can use as a baseline for C++ however: http://social.msdn.microsoft.com/Forums/en-US/winappswithhtml5/thread/a038defe-2594-4c1a-85ef-7a98a0a409b2

If you have troubles translating this to C++ you can hit up the Metro C++ forum for assistance.

-Jeff

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Jeff Sanders (MSFT)

Answer 2

Take a look at this:

http://blogs.msdn.com/b/nativeconcurrency/archive/2011/10/27/try-it-now-use-ppl-to-produce-windows-8-asynchronous-operations.aspx

Raman