Aspnetcore: [assembly: Microsoft.AspNetCore.Identity.UI.UIFrameworkAttribute("Bootstrap4")] causing The type or namespace name 'UI' does not exist in the namespace 'Microsoft.AspNetCore.Identity'

[kofifus]

Since upgrading to VS19 16.6.0 Preview 1.0 with latest .NET Core 3.1.2 this morning my project does not build.

I get an error in myproj.AssemblyInfo.cs in

[assembly: Microsoft.AspNetCore.Identity.UI.UIFrameworkAttribute("Bootstrap4")]

Error CS0234 The type or namespace name 'UI' does not exist in the namespace 'Microsoft.AspNetCore.Identity' (are you missing an assembly reference?)

In Manage NuGet Packages I see I have installed Microsoft.AspNetCore.Identity.UI 5.0.0-preview.1.20124.5

csproj:

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <RuntimeIdentifier>win7-x64</RuntimeIdentifier>
    <IsTransformWebConfigDisabled>true</IsTransformWebConfigDisabled>    
    <UserSecretsId>...</UserSecretsId>
    <AspNetCoreHostingModel>inprocess</AspNetCoreHostingModel>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore" Version="3.1.2" />
    <PackageReference Include="Microsoft.AspNetCore.Hosting.WindowsServices" Version="3.1.2" />
    <PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="5.0.0-preview.1.20124.5" />
    <PackageReference Include="Microsoft.AspNetCore.Identity.UI" Version="5.0.0-preview.1.20124.5" />
    <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="5.0.0-preview.1.20124.5" />
    <PackageReference Include="Microsoft.AspNetCore.SignalR.Protocols.NewtonsoftJson" Version="5.0.0-preview.1.20124.5" />
    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="5.0.0-preview.2.20120.8" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="5.0.0-preview.2.20120.8" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="5.0.0-preview.2.20120.8" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="5.0.0-preview.2.20120.8" />
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="3.1.1" ExcludeAssets="All" />
    <PackageReference Include="NETStandard.Library" Version="2.0.3" />
    <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
    <PackageReference Include="Serilog.AspNetCore" Version="3.3.0-dev-00152" />
    <PackageReference Include="System.Data.SqlClient" Version="4.8.1" />
    <PackageReference Include="System.IO.FileSystem.Primitives" Version="4.3.0" />
    <PackageReference Include="System.Text.Encoding.Extensions" Version="4.3.0" />
    <PackageReference Include="System.Runtime.Handles" Version="4.3.0" />
    <PackageReference Include="Serilog.Sinks.File" Version="5.0.0-dev-00864" />
  </ItemGroup>

</Project>

Any help please ?

[javiercn]

@kofifus thanks for contacting us.

Seems to me that you have mismatched versions of packages. You should be using 3.1.X packages that are RTM with netcoreapp3.1, not 5.0.0-preview1-XXXX packages.

[kofifus]

Thanks @javiercn , I confused here .. it seems that since the latest update, when you tick "Include prerelease" in "Manage NuGet Packages for Solution" it beings the 5.0.0-preview1-XXXX ... does that mean there are no longer prereleases on the 3.1.x ??

[javiercn]

3.1 has been RTM since november of last year.

[kofifus]

OK thanks.. does that means I should not have "Include prerelease" ticked when using .NET Core ?

[blowdart]

Only if you want to experiment with 5 :)