Everything was rolling along smoothly until a few days ago when UWP all of a sudden stopped building after pulling a new version from VSTS (git) with the errors:
Cannot resolve Assembly or Windows Metadata file 'Type universe cannot resolve assembly: X.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null.'
Could not copy the file "obj\x86\Debug\MainPage.xbf" because it was not found.
Could not copy the file "obj\x86\Debug\App.xbf" because it was not found.
Could not copy the file "obj\x86\Debug\X.Mobile.UWP.xr.xml" because it was not found.
I have a solution structure of the following:
X.Core (.NET Standard class library)
X.Mobile (.NET Standard PCL)
X.Mobile.UWP (UWP specific project)
UWP references Mobile, and Mobile references Core (Core is also referenced by a web API project).
The commit that I pulled from source control did not have any changes to the X.Mobile.UWP .csproj file.
Things I have tried:
The obligatory clean and rebuild.
Delete all obj and bin folders for the entire solution.
Remove and re-add all references in the .UWP project.
Upgrade Xamarin.Forms to the latest stable (3.1.0.637273).
Remove and re-add X.Core reference in the X.Mobile project.
Delete C:\Users\%username%.nuget folder.
Update Microsoft.NETCore.UniversalWindowsPlatform to the latest stable (6.1.5).
Change the target version to all available versions - we've been running on build 16299 for several months.
And I've been beating my head against this problem on and off for days now. Android and iOS projects build just fine, which is ironic considering UWP has been our most stable platform. Anyone have any insight?
EDIT:
After adding a reference to X.Core directly to the X.Mobile.UWP project, I can compile. This shouldn't be the answer though since UWP never directly references Core.
I found the solution.
I had the very same problem because I had added a new (.Net Standard 2.0 Class Library) project into my Xamarin.Forms solution.
In short, initially my solution included the following projects:
BackgroundTaskTest (which have all my Views and ViewModels)
BackgroundTaskTest.Android
BackgroundTaskTest.iOS
BackgroundTaskTest.UWP
Suddenly I decided to add a class library named "BackgroundTaskTest.Common" in the same solution folder:
BackgroundTaskTest.Common (new one)
BackgroundTaskTest (which have all my Views and ViewModels)
BackgroundTaskTest.Android
BackgroundTaskTest.iOS
BackgroundTaskTest.UWP
The Android was working fine with it but the UWP project didn't like that new neighbor (which in your case is named "X.Core"). So I moved my classes from that new project to the "BackgroundTaskTest" again and deleted "BackgroundTaskTest.Common" from my solution with all the references and it has started working.
To finalize and make it short, please compare your X.Mobile.csproj file with X.Mobile.Core.csproj file. you will find the issue in the differences. Plus try to check all your dependencies to the X.Core project to make sure they are the same.
I installed NuGet package "NETStandard.Library" and added a reference to all my .Net Standard libraries to my UWP project. This solved the problem for me!
Related
I am making a crossplatform xamirin forms application that should run on android and pc windows.
During compiling the UWP version I get the exceptions:
Can not resolve Assembly or Windows Metadata file
'Xamarin.Forms.Platform.WP8.dll
and
Type universe can not resolve assembly: Xamarin.Forms.Platform.WP8,
Version = 1.5.0.0, Culture = neutral, PublicKeyToken = null
I read about these exceptions on the internet and from what I could see, it is related to the Xlabs plugin being used in the application. Is this information correct?
If yes, would I have some way to fix it without removing the Xlabs plugin, why am I using it on multiple forms to be able to checkboxes.
I faced this issues because of Nuget package was not up to date in my every project. I tried to fix this issues using below step.
Close the Visual Studio/Xamarin Studio.
Delete the Nuget package folder from root directory.
Delete the all bin, obj and debug folder from every project folder.
Right click on every project of Package folder and try to update.
Clean the all solution and Rebuild all.
I've got a cross platform (iOS and Android) Xamarin solution using .NET Standard 2.0. The solution is being built by Visual Studio 2017 (I've tried both the current and preview versions). The Forms and Android projects build fine. However, the iOS fails to build, with the following error:
1>CSC : error CS1703: Multiple assemblies with equivalent identity have been imported: 'C:\Users\newuser.nuget\packages\system.reflection.emit\4.3.0\ref\netstandard1.1\System.Reflection.Emit.dll' and 'C:\Program Files (x86)\Microsoft Visual Studio\Preview\Enterprise\Common7\IDE\ReferenceAssemblies\Microsoft\Framework\Xamarin.iOS\v1.0\Facades\System.Reflection.Emit.dll'. Remove one of the duplicate references.
I've tried many work arounds as described here:
oren.codes
www.hanselman.com
github.com/NuGet
Unfortunately none of these suggestions work. I have also tried to add the System.Reflection.Emit nuget package directly to the Forms and/or to the iOS projects directly. This doesn't work either. Note that originally, the The System.Reflection.Emit package wasn't referenced directly by anything in the solution. It is being pulled in by the following nuget packages which are being explicitly referenced:
Acr.DeviceInfo (5.0.5)
akavache (6.0.0-alpha0038)
AutoMapper (6.2.2)
Microsoft.Identity.Client (1.1.1-preview0040)
Newtonsoft.Json (10.0.3)
Finally, I have tried the update-package -reinstall command in the package console to reinstall all packages for the iOS project. This doesn't work either.
-- update
Just to make this clear, neither the Xamarin Forms or the Xamarin iOS project directly reference System.Reflection.Emit. That package is being pulled in as a dependency of other nuget packages, just from packages that are installed into the Xamarin Forms project. I have confirmed all of the dependencies that are referenced by Nuget, are using the same version. See these screenshots:
It seems to me that the problem (as the error says) is that there is an old version of System.Reflection.Emit that was installed by Visual Studio. However, I can't find a way of ignoring it and using the version of System.Reflection.Emit instead. As I've said above, I have tried to use a project.json file in the Xamarin.iOS project, and manually ignoring, but this doesn't work.
Does anyone else have any ideas?
As an aside, I notice that this bug is still open for Xamarin.
Xamarin Bugs
Managed to get this resolved thanks to an answer by #DirkWilhem on Xamarin Forums site.
Basically, add this to your Xamarin iOS project's .csproj file, with the other PackageReference nodes:
<PackageReference Include="System.Reflection.Emit">
<Version>4.3.0</Version>
<ExcludeAssets>all</ExcludeAssets>
</PackageReference>
Of course you need to make sure the nuget package has been added to the iOS package first.
Xamarin Forums discussion
After spending hours trying to resolve this myself I may have found a solution. Although it does feel wrong, it has got me past the issue.
Moving/Deleting the Xamarin.iOS version of System.Reflection.Emit.dll has solved the build problem for me and enabled me to deploy and run my app on a device. I don’t know what side effects it might have so will need more testing but I thought I’d share what’s worked for me so you can test it as well.
I was running on macOS Visual Studio 2017 but switched over to Windows to try and fix and first fixed on there then tried same approach on macOS and it worked as well.
On windows, go into the following directory and move the System.Reflection.Emit.dll somewhere else (you could just straight up delete it but I wanted to keep a copy I case this has some undesired effects down the track):
C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\ReferenceAssemblies\Microsoft\Framework\Xamarin.iOS\v1.0\Facades
On mac the following directory has it:
/Library/Frameworks/Xamarin.iOS.framework/Versions/Current/lib/mono/Xamarin.iOS/Facades
Like I say, it feels wrong but for now it’s got me past an issue that’s had me blocked for a couple of days so willing to just move on and hope there’s no side effects. I’d be interested to know your experience with it and if you come across anything else for the future too.
I’ll post this same comment on the Xamarin forums post (https://forums.xamarin.com/discussion/120814/xamarin-ios-project-cs1703-multiple-assemblies-with-equivalent-identity-have-been-imported) as well for future reference.
I had the same issue around a custom Nuget packages that we created and consumed in a separate project. We got around this issue by removing the automatic Nuget building checkbox in the "options" for the project. This does add the extra step of "Create Nuget Package" but one we pushed it to our Nuget repo and consumed it in our project, the errors vanished.
The problem showed up when we updated the sub-projects from PCLs to .netstandards (2.0).
About: I have a ASP.NET website (not Web project) with 3 class library projects in the solution. Earlier I was using SVN but now Git is used source management. I have installed the git locally on a computer (used as server) and using it for merging the source code from other developers. Also, I am using Visual studio 2015 community edition which provides the tools to work with git.
Problem: After cloning the project from the master repository, I build the project to run it. Building the project shows a dialog box saying "Package Restore is in progress". This process creates a folder named "Packages" and that folder includes every package listed in the packages.config file. But after restoration completes, the project throws the following exception:
This exception shows for each package (Autofac here).
The type or namespace name 'Autofac' could not be found (are you missing a using directive or an assembly reference?)
Work around To Solve this problem, I need to uninstall each package and installed it again and problem is solved. This thing I need to do again and again for each developer machine, which is frustrating and time consuming too.
Does anyone has faced the same problem working with Nuget, git and website in ASP.NET.
I faced a problem like this before. In my case, the reason was that I changed the project path (moved the project to another directory), and the path of the packages directory (that contains the NuGet packages) was stored in the csproj file for the old path, that is VS cannot restore NuGet packages. The solution for this was to edit the csproj manually and make it referring to the correct new packages path.
If this doesn't work for you, you can still use your workaround, but using the following PowerShell command (in NuGet Console) for simplicity:
Update-Package -reinstall -Project Your.Project.Name
Note: project name doesn't contain csproj extension, just the project name
It is good practice to not put third party packages into source control. It bloats your repository (even on a large web application, the size of the external packages will massively out weigh your code).
If NuGet package restore is slow, you could look at using a local cache (this can be as simple as a shared folder) or a better internet connection.
That said, you should only have this problem once per machine. While the packages are downloading you could be giving the new team member an overview of the design…
Make sure that all of your projects are using the same target framework, when this isn't done you can often get the
type or namespace [name] could not be found
warning.
To do this, right click each of the projects in the solution explorer > Properties > Application tab > Target Framework. They should all be the same or there will be incompatibilities between the references in your projects. Here's a question regarding this, hopefully this helps.
The main reason is there no Autofac reference in packages.config file.
When you see on the screen Restore packages message box this mean that nuget package manager is trying to install all the packages which are missing in the package folder.
Try to do this step:
In Visual Studio Solution Explorer pick the project and via context menu pick Unload project
After project was unloaded via context menu pick Edit your project
Go to section group and find you Autofac Reference section
If HintPath doesnt looks like ..\packages\Autofac.4.1.1\lib\net45\Autofac.dll (Actual for 4.1.1 version) remove the Autofac reference Item
Save csproj file and reload project
Install Autofac via NuGet Package manager
Commit and push changes to git repository
Had the same problem with VS 2019. In ASP.NET, packages are updated via the .refresh files that appear in your bin folders. If these aren't checked into Git, they wouldn't be copied down to your cloned repro.
I added the .refresh files for all of my package dlls, made sure the versions and paths in the .refresh files were correct, and now everything updates as expected.
My custom class library (targeting .NET 4.5.1) references Newtonsoft.Json 8.0.2 (the latest version to date). I've added this class library as a reference to a new ASP.NET 5 Web API project.
From the Error List output:
Error NU1002 The dependency Newtonsoft.Json 1.0.0 in project MyProject does not support framework DNXCore,Version=v5.0.
That part seems somewhat self-explanatory, however, I couldn't understand why it was changing my referenced version to 1.0.0.
From the References --> DNX 4.5.1 --> MyClassLibrary Node:
NU1007 Dependency specified was Newtonsoft.Json >= 8.0.2 but ended up with Newtonsoft.Json 1.0.0.
I've tried removing/re-adding the references several times, all to no avail. I did notice that several of the ASP.NET libraries use Newtonsoft.Json 6.0.6 -- I'm not sure if this has anything to do with it.
If I navigate to the wrap folder --> Newtonsoft.Json --> json file, and replace "Newtonsoft.Json 1.0.0-*" with "Newtonsoft.Json 8.0.2-*", it fixes the references for the DNX 4.5.1 node.
However, errors still show afterwards saying that Newtonsoft.Json 8.0.2 referenced in my class library does not support DNXCore 50.
I'm at a loss as to what to do. Any help would be greatly appreciated.
Answer to my issue:
Thanks to Oleg's response I was able to make it work -- however there were two hurdles. One was the "wrap" folder that was created for Newtonsoft.Json. In the root of my solution was a "wrap" folder that contained a folder called Newtonsoft.Json. Apparently(?) that folder shouldn't have been created (how it was created I have no idea). Once removing that, I was able to add a reference to my custom class library without any errors referencing Newtonsoft.Json.
However when I began trying to use my custom assembly as in code, I would get an error about DNX50 not being supported -- which sort've makes sense because my custom referenced assembly was a .NET 4.5.1 class library.
This GitHub link has many people experiencing a similar issue
However, I managed to get everything to build and errors to go away by removing targeting for DNXCore50. This worked for me because I was just wanting to share some POCO data models between a Web API and WPF project. I'm not interested in targeting DNXCore at the moment.
I'm looking forward to the future of ASP.NET, but the newness is a bit challenging, at least for me.
All,
I am struggling to get off the ground with SQLite. I cannot seem to find the right search terms to get the answer I need, so have come here.
I simply want to do this: have a single dll (PCL) that contains all my SQLite logic. I have installed the NuGet package SQLitePCL from Microsoft Open Technologies into this PCL project. I have written a single method that opens a connection.
I then have a test harness console application that references my PCL DLL project. That, in its root, has the file SQLite3.dll, that I downloaded from the SQLite site. Obviously, this console application calls my OpenConnection method in the library dll.
I am getting the error:
Additional information: A SQLite Wrapper assembly for the current platform was not found. Ensure that the current project references both SQLitePCL and the following platform-specific assembly: SQLitePCL.Ext
So my questions are:
where do I get that platform specific assembly from?
Is there an article on the web that specifically demonstrates how to do this?
Help gratefully appreciated,
Gray
Ok ... the answer to this was painfully simple. The platform specific assemblies are in the "packages\SQLitePCL.3.8.5.1\build" folder (put there by NuGet, of course). I just copied the dll from the sub folder Netcore451 into the root of my console app.