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Created attachment 9219 [details]
I am following "Creating Mobile Apps with Xamarin.Forms" book by Charles Petzold for learning Xamarin.Forms
In chapter 3, Version 6 of the App, when the async methods were tried to created in the interface to be used for DependencyService for PCL project, the error encoutered.
Basically the problem is that when the return type of the Method is set to be Task (for async methods) in the interface, and then the class in platform projects the class implements the interface, the windows phone project works just fine, but the android and iOS projects
Error CS0738 'FileHelper' does not implement interface member 'IFileHelper.ExistsAsync(string)'. 'FileHelper.ExistsAsync(string)' cannot implement 'IFileHelper.ExistsAsync(string)' because it does not have the matching return type of 'Task<bool>'.
But you can clearly see in the Attached screenshot that Task<bool> is the return type of the ExistsAsync method in the Android Project (the one in the center)
The same error is reported 3 times, one for each method.
We have checked this issue and unable to reproduce this issue .
Could you please provide us sample project and build info ,so that we can able to reproduce this issue at our end.?
You can copy build info from here
In VS ->Help ->About Microsoft visual studio and copy info.
Created attachment 9268 [details]
Adding Dependency assembly on the top gets me a few errors, applying this quick fix creates the actual error that I actually posted about.
Created attachment 9269 [details]
Created attachment 9271 [details]
A Project in which the quick fix is applied, and hence the System.Runtime Library is added.
I have added some more attachments.
I have actually resolved the issue, but prior to building the solution, Visual Studio keeps on showing that there are errors in the Code.
Can you clear out about what can be done about it?
By the way, thank you very much for the response from your side, it made me once again open my project after so many days and start pondering on it again, and hence helping me out to resolve the issue :D
I have checked this issue and able to reproduce this issue with the help of bug description and comment 4.
Screencast : http://www.screencast.com/t/jdVh3i2T
Ide log : https://gist.github.com/RamChBachkheti/a602327b8be49fafec63
Error : https://gist.github.com/RamChBachkheti/7ee89af4da87ea34247b
Microsoft Visual Studio Professional 2013
Version 12.0.30723.00 Update 3
Microsoft .NET Framework
Installed Version: Professional
Xamarin 18.104.22.168 (10cfd178d55287f09c85f5a1e604dfe20889a40f)
Visual Studio extension to enable development for Xamarin.iOS and Xamarin.Android.
Xamarin.Android 22.214.171.124 (ba9bbbdd44cfdc4bf485e8885bd2ad24fba525f7)
Visual Studio plugin to enable development for Xamarin.Android.
Xamarin.iOS 126.96.36.199 (840a925103a0bf4a856507f13d5eaee3c1579c2f)
Visual Studio extension to enable development for Xamarin.iOS.
Xamarin.iOS Unified Migration 1.0
Automated migration for Xamarin iOS Classic projects to Unified
Reproduced this issue.
Class in Android project implements interface from PCL project.
Microsoft Visual Studio Ultimate 2015 Preview
Version 14.0.22310.1 DP
Microsoft .NET Framework Version 4.5.53349
Installed Version: Ultimate
How did you resolve the issue?
By removing the System.Runtime Library's Reference from the Projects.
Though is shows that the error is there while writing code, but it builds without any errors.
Any update on this bug? This is a serious bug for us and we are hoping that it gets fixed as soon as possible.
I have got no idea about the next steps.
The team was able to reproduce the issue and have marked its status as CONFIRMED. Most probably they are working on it now.
It is fixed in Xamarin Forms version 1.3.4
No longer happens with latest Xamarin + X.F.