Trying to convert an IEnumerable<Guid?> to a IList<Guid> but cannot find proper documentation. RRS feed

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  • Greetings Joey.

    I don't understand the question. There's nothing on that line that tries to convert an IEnumerable to an IList. What exactly is the error you are getting?

    Tuesday, July 9, 2019 11:20 PM
  • Hi Joey,

    Thank you for posting here.

    Since this thread is related to Azure, we don't support it. I suggest that you could send the feedback in the link you provided.

    The Visual C# forum discusses and asks questions about the C# programming language, IDE, libraries, samples, and tools.

    Best Regards,


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    Wednesday, July 10, 2019 5:47 AM
  • Hello,

    all you have is to use Select method to project the result in List<Guid> :

    var ids = faceIds
       .Where(r => r.HasValue) // here we filter the list based on the HasValue property    
       .Select(r => r.Value).ToList<Guid>(); 
    var results = await faceClient.Face.IdentifyAsync(ids, personGroupId);

    Best regards;

    Wednesday, July 10, 2019 8:40 AM
  • So `FaceClient.Face.IdentifyAsync` requires an IList<Guid> as the first parameter but your `faceIds` variable is of type `IEnumerable<Guid>`? To convert an `IEnumerable<Guid>` to `List<Guid>` (which implements `IList<Guid>`) use the `ToList` method from LINQ.

    var results = await faceClient.Face.IdentifyAsync(faceIds.ToList(), personGroupId);
    Note that you should only use `ToList` when you need an actual list and/or you need to force enumeration of the results (aka coming back from a database call).

    Michael Taylor http://www.michaeltaylorp3.net

    Wednesday, July 10, 2019 2:08 PM
  • My apologies the question was a little ambiguous,

    The identifyAsync() requires faceIds to be an IList<Guid>, however the tutorial autotypes faceIds to an Guid?[]. I get an error when I try to run this code. What suggestions do y'all have to fix this? 

    I tried the above suggestion from Cherkaoui.Mouad and It is still giving me an error, for it is not letting me add the <Guid> to ToList(), for it takes the same type it was applied to. 

    Wednesday, July 10, 2019 2:10 PM
  • I got everything working. Thanks to everyone for the help!
    Wednesday, July 10, 2019 2:22 PM
  • Hi, 

    I think that you should add using for :

    using System.Linq;
    using System.Collections.Generic;

    anyway it should work with ToList() since the projected value is a Guid.

    Good Coding;

    Wednesday, July 10, 2019 3:12 PM