Xamarin UWP - Fingerprint reader - Digital Persona U.are.U

Jerry Johansson 1

I'm having trouble connecting to my attached (USB) Digital Persona Crossmatch fingerprint reader in UWP. (Using Win Forms - ok).

I've added the dependent dll: DPUruNet.dll as a reference.

When I run my small code sample:

     *using DPUruNet; 
      ... ` 
      var readers = ReaderCollection.GetReaders(); **// fail***

I get the exception "Unable to load DLL 'dpfpdd.dll' or one of its dependencies. Access is denied".

I can't add the dpfpdd.dll as a reference. VS2019 is not allowing the dll.
Is the depending dpfpdd.dll a "not trust" or not allowed x86 dll?
Is there some way I can allow/access dependent dll's in my UWP Xamarin Forms app?

The code works in a Win Forms project, can read my fingerprint etc... Kind regards, Jerry

Jerry Johansson 1 Reputation point

2021-03-22T02:56:13.347+00:00
I have checked/ticked off:

Remote System

Removable Storage (USB etc)

Low Level

Low Level Devices

in Cababilities in Package.appmanifest to allow for connected devices.
The problem seems related to dependent, not allowed dll's etc.
/ Jerry
Roy Li - MSFT 33,586 Reputation points Microsoft Vendor

2021-03-22T06:10:00.91+00:00

Currently, Microsoft Q&A supports the products listed over here: supported topics (more to be added later on).

Your question about using a third-party dll is not supported. You might need to contact the author of the dll to check this issue.

By the way, there is a NuGet version of this library and maybe you could try that.

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