cannot resolve assembly or windows metadata file "Mono.Android.dll"

2
votes

I have been using Xamarin's cross platform capabilities in Visual Studio and am using the UWP to debug. I have been working for a while and this error suddenly appeared.

Type universe cannot resolve assembly: Mono.Android, Version=0.0.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065.
Cannot resolve Assembly or Windows Metadata file 'Mono.Android.dll'

I have reinstalled visual studio and closed/ reopened the project. I have also cleared the nugget cache. I have even downloaded the android sdk and installed as many packages as possible. I have been opening the file where this error occurs but I don't see the problem. I think I have somehow missed a package but I don't know what to do.

.csproj code

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
  <PropertyGroup>
    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
    <Platform Condition=" '$(Platform)' == '' ">x86</Platform>
    <ProjectGuid>{FAEE398B-7B29-4F06-9680-AC61EAC98C26}</ProjectGuid>
    <OutputType>AppContainerExe</OutputType>
    <AppDesignerFolder>Properties</AppDesignerFolder>
    <RootNamespace>ApPOYNTments.UWP</RootNamespace>
    <AssemblyName>ApPOYNTments.UWP</AssemblyName>
    <DefaultLanguage>en-US</DefaultLanguage>
    <TargetPlatformIdentifier>UAP</TargetPlatformIdentifier>
    <TargetPlatformVersion>10.0.15063.0</TargetPlatformVersion>
    <TargetPlatformMinVersion>10.0.10586.0</TargetPlatformMinVersion>
    <MinimumVisualStudioVersion>14</MinimumVisualStudioVersion>
    <EnableDotNetNativeCompatibleProfile>true</EnableDotNetNativeCompatibleProfile>
    <FileAlignment>512</FileAlignment>
    <ProjectTypeGuids>{A5A43C5B-DE2A-4C0C-9213-0A381AF9435A};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
    <PackageCertificateKeyFile>ApPOYNTments.UWP_TemporaryKey.pfx</PackageCertificateKeyFile>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|ARM'">
    <DebugSymbols>true</DebugSymbols>
    <OutputPath>bin\ARM\Debug\</OutputPath>
    <DefineConstants>DEBUG;TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
    <NoWarn>;2008</NoWarn>
    <DebugType>full</DebugType>
    <PlatformTarget>ARM</PlatformTarget>
    <UseVSHostingProcess>false</UseVSHostingProcess>
    <ErrorReport>prompt</ErrorReport>
    <Prefer32Bit>true</Prefer32Bit>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|ARM'">
    <OutputPath>bin\ARM\Release\</OutputPath>
    <DefineConstants>TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
    <Optimize>true</Optimize>
    <NoWarn>;2008</NoWarn>
    <DebugType>pdbonly</DebugType>
    <PlatformTarget>ARM</PlatformTarget>
    <UseVSHostingProcess>false</UseVSHostingProcess>
    <ErrorReport>prompt</ErrorReport>
    <Prefer32Bit>true</Prefer32Bit>
    <UseDotNetNativeToolchain>true</UseDotNetNativeToolchain>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x64'">
    <DebugSymbols>true</DebugSymbols>
    <OutputPath>bin\x64\Debug\</OutputPath>
    <DefineConstants>DEBUG;TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
    <NoWarn>;2008</NoWarn>
    <DebugType>full</DebugType>
    <PlatformTarget>x64</PlatformTarget>
    <UseVSHostingProcess>false</UseVSHostingProcess>
    <ErrorReport>prompt</ErrorReport>
    <Prefer32Bit>true</Prefer32Bit>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x64'">
    <OutputPath>bin\x64\Release\</OutputPath>
    <DefineConstants>TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
    <Optimize>true</Optimize>
    <NoWarn>;2008</NoWarn>
    <DebugType>pdbonly</DebugType>
    <PlatformTarget>x64</PlatformTarget>
    <UseVSHostingProcess>false</UseVSHostingProcess>
    <ErrorReport>prompt</ErrorReport>
    <Prefer32Bit>true</Prefer32Bit>
    <UseDotNetNativeToolchain>true</UseDotNetNativeToolchain>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x86'">
    <DebugSymbols>true</DebugSymbols>
    <OutputPath>bin\x86\Debug\</OutputPath>
    <DefineConstants>DEBUG;TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
    <NoWarn>;2008</NoWarn>
    <DebugType>full</DebugType>
    <PlatformTarget>x86</PlatformTarget>
    <UseVSHostingProcess>false</UseVSHostingProcess>
    <ErrorReport>prompt</ErrorReport>
    <Prefer32Bit>true</Prefer32Bit>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
    <OutputPath>bin\x86\Release\</OutputPath>
    <DefineConstants>TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
    <Optimize>true</Optimize>
    <NoWarn>;2008</NoWarn>
    <DebugType>pdbonly</DebugType>
    <PlatformTarget>x86</PlatformTarget>
    <UseVSHostingProcess>false</UseVSHostingProcess>
    <ErrorReport>prompt</ErrorReport>
    <Prefer32Bit>true</Prefer32Bit>
    <UseDotNetNativeToolchain>true</UseDotNetNativeToolchain>
  </PropertyGroup>
  <ItemGroup>
    <!-- A reference to the entire .Net Framework and Windows SDK are automatically included -->
    <None Include="project.json" />
  </ItemGroup>
  <ItemGroup>
    <Compile Include="App.xaml.cs">
      <DependentUpon>App.xaml</DependentUpon>
    </Compile>
    <Compile Include="MainPage.xaml.cs">
      <DependentUpon>MainPage.xaml</DependentUpon>
    </Compile>
    <Compile Include="Properties\AssemblyInfo.cs" />
    <Compile Include="UnitTest.cs" />
  </ItemGroup>
  <ItemGroup>
    <AppxManifest Include="Package.appxmanifest">
      <SubType>Designer</SubType>
    </AppxManifest>
    <None Include="ApPOYNTments.UWP_TemporaryKey.pfx" />
  </ItemGroup>
  <ItemGroup>
    <Content Include="Properties\Default.rd.xml" />
    <Content Include="Assets\LockScreenLogo.scale-100.png" />
    <Content Include="Assets\LockScreenLogo.scale-125.png" />
    <Content Include="Assets\LockScreenLogo.scale-150.png" />
    <Content Include="Assets\LockScreenLogo.scale-200.png" />
    <Content Include="Assets\LockScreenLogo.scale-400.png" />
    <Content Include="Assets\SplashScreen.scale-100.png" />
    <Content Include="Assets\SplashScreen.scale-125.png" />
    <Content Include="Assets\SplashScreen.scale-150.png" />
    <Content Include="Assets\SplashScreen.scale-200.png" />
    <Content Include="Assets\SplashScreen.scale-400.png" />
    <Content Include="Assets\Square150x150Logo.scale-200.png" />
    <Content Include="Assets\Square44x44Logo.scale-100.png" />
    <Content Include="Assets\Square44x44Logo.scale-125.png" />
    <Content Include="Assets\Square44x44Logo.scale-150.png" />
    <Content Include="Assets\Square44x44Logo.scale-200.png" />
    <Content Include="Assets\Square44x44Logo.scale-400.png" />
    <Content Include="Assets\Square44x44Logo.targetsize-16_altform-unplated.png" />
    <Content Include="Assets\Square44x44Logo.targetsize-24_altform-unplated.png" />
    <Content Include="Assets\Square44x44Logo.targetsize-32_altform-unplated.png" />
    <Content Include="Assets\Square44x44Logo.targetsize-48_altform-unplated.png" />
    <Content Include="Assets\Square44x44Logo.targetsize-256_altform-unplated.png" />
    <Content Include="Assets\StoreLogo.png" />
    <Content Include="Assets\Wide310x150Logo.scale-100.png" />
    <Content Include="Assets\Wide310x150Logo.scale-125.png" />
    <Content Include="Assets\Wide310x150Logo.scale-150.png" />
    <Content Include="Assets\Wide310x150Logo.scale-200.png" />
    <Content Include="Assets\Wide310x150Logo.scale-400.png" />
  </ItemGroup>
  <ItemGroup>
    <ApplicationDefinition Include="App.xaml">
      <Generator>MSBuild:Compile</Generator>
      <SubType>Designer</SubType>
    </ApplicationDefinition>
    <Page Include="MainPage.xaml">
      <Generator>MSBuild:Compile</Generator>
      <SubType>Designer</SubType>
    </Page>
  </ItemGroup>
  <ItemGroup>
    <Reference Include="PoyntSDK1.2.107">
      <HintPath>..\..\..\..\..\Documents\Poynt Output-Build\PoyntSDK1.2.107.dll</HintPath>
    </Reference>
  </ItemGroup>
  <PropertyGroup Condition=" '$(VisualStudioVersion)' == '' or '$(VisualStudioVersion)' &lt; '14.0' ">
    <VisualStudioVersion>14.0</VisualStudioVersion>
  </PropertyGroup>
  <Import Project="..\ApPOYNTments\ApPOYNTments.projitems" Label="Shared" Condition="Exists('..\ApPOYNTments\ApPOYNTments.projitems')" />
  <Import Project="$(MSBuildExtensionsPath)\Microsoft\WindowsXaml\v$(VisualStudioVersion)\Microsoft.Windows.UI.Xaml.CSharp.targets" />
  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
       Other similar extension points exist, see Microsoft.Common.targets.
  <Target Name="BeforeBuild">
  </Target>
  <Target Name="AfterBuild">
  </Target>
  -->
</Project>

UPDATE: I found this error, it seems to be an internal problem

1>C:\Users\dedawg\Documents\Visual Studio 2017\ArchitectureExplorer\MSBuild\Microsoft\WindowsXaml\v15.0\8.2\Microsoft.Windows.UI.Xaml.Common.targets(354,5): Xaml Internal Error error WMC9999: Type universe cannot resolve assembly: Mono.Android, Version=0.0.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065.

Here is the certain part that the file is pointing to.

 <CompileXaml
            LanguageSourceExtension="$(DefaultLanguageSourceExtension)"
            Language="$(Language)"
            RootNamespace="$(RootNamespace)"
            XamlPages="@(Page)"
            XamlApplications="@(ApplicationDefinition)"
            SdkXamlPages="@(SdkXamlItems)"
            PriIndexName="$(PriIndexName)"
            ProjectName="$(MsBuildProjectName)"
            IsPass1="False"
            DisableXbfGeneration="$(DisableXbfGeneration)"
            CodeGenerationControlFlags="$(XamlCodeGenerationControlFlags)"
            ClIncludeFiles="@(ClInclude)"
            CIncludeDirectories="$(XamlCppIncludeDirectories)"
            LocalAssembly="$(LocalAssembly)"
            ProjectPath="$(MSBuildProjectFullPath)"
            OutputPath="$(XamlGeneratedOutputPath)"
            OutputType="$(OutputType)"
            ReferenceAssemblyPaths="@(ReferenceAssemblyPaths)"
            ReferenceAssemblies="@(XamlReferencesToCompile)"
            ForceSharedStateShutdown="False"
            CompileMode="RealBuildPass2"
            XAMLFingerprint="$(XAMLFingerprint)"
            FingerprintIgnorePaths="$(XAMLFingerprintIgnorePaths)"
            VCInstallDir="$(VCInstallDir)"
            WindowsSdkPath="$(WindowsSdkPath)"
            SavedStateFile="$(XamlSavedStateFilePath)"
            RootsLog="$(XamlRootsLog)"
            SuppressWarnings="$(SuppressXamlWarnings)"
            TargetPlatformMinVersion="$(TargetPlatformMinVersion)"
            BuildConfiguration="$(Configuration)"
            DisableXbfLineInfo="$(DisableXbfLineInfo)">
      <Output Condition=" '$(ManagedAssembly)'!='false' " ItemName="Compile"   TaskParameter="GeneratedCodeFiles" />
      <Output Condition=" '$(ManagedAssembly)'=='false' " ItemName="XamlGFiles" TaskParameter="GeneratedCodeFiles" />

      <!--
      FileWrites is used in Microsoft.Common.Targets for "Clean" build 
      -->
      <Output ItemName="FileWrites" TaskParameter="GeneratedCodeFiles" />
      <Output ItemName="FileWrites" TaskParameter="GeneratedXamlFiles" />
      <Output ItemName="FileWrites" TaskParameter="GeneratedXbfFiles" />
      <Output ItemName="_GeneratedCodeFiles" TaskParameter="GeneratedCodeFiles" />
      <Output ItemName="_GeneratedXamlFiles" TaskParameter="GeneratedXamlFiles" />
      <Output ItemName="_GeneratedXbfFiles" TaskParameter="GeneratedXbfFiles" />
    </CompileXaml>
1
c#androidvisual-studioxamarin
It seems your UWP project has a MonoAndroid reference, try removing this reference from your UWP.csproj file. - Eren Shen
I have just opened up my UWP file and there is no reference. However I believe you're answer is correct, let me keep searching. @YorkShen-MSFT - DanielKBoyer
Would you mind share a basic demo that can reproduce the problem through online repo ? To make sure we are verifying the exact same thing you are using. - Eren Shen
The problem is I cannot publicly show this project, but I have found a link to a similar problem and I believe the solution is what you're saying. - DanielKBoyer
Please post your UWP.csproj code. - Eren Shen

1 Answers

1
votes

Following this links instructions should solve the problem for most people looking here. I figured out the error. In my reference I have added a Poynt library. Although this isn't Mono.Android it contained the reference. Removing that library fixed the issue, however I do need that library but that is another question.