.NET Core 3.0 Preview Known Issues

This document lists known issues for .NET Core 3.0 Preview releases which may be encountered during usage.

ASP.NET Core

Preview 3

Updates to .razor files fail to show up in subsequent builds: Updates to Razor Component (.razor) in Visual Studio may fail to show up in subsequent builds. To work around this issue add the following item group to the project file:
```
<ItemGroup>
    <UpToDateCheckInput Include="@(Content->WithMetadataValue('Extension', '.razor'))" />
</ItemGroup>
```
Updates to Razor Components in .razor files fail to show up in IntelliSense: Updates to Razor Components defined in .razor files may fail to show up in IntelliSense in Visual Studio. To workaround this issue rebuild the project.

Single Page Applications with authentication enabled throws method not found exception when visiting the register or login pages: The exception message is the one below. Method not found: 'Microsoft.EntityFrameworkCore.Metadata.Builders.IndexBuilder Microsoft.EntityFrameworkCore.Metadata.Builders.EntityTypeBuilder``1.HasIndex(System.Linq.Expressions.Expression``1<System.Func``2<!0,System.Object>>)'. To workaround this issue follow these steps:

Replace the following package references with the ones below in your csproj folder:

<PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="3.0.0-preview3-19153-02" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="3.0.0-preview3.19153.1" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="3.0.0-preview3.19153.1" />

<PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="3.0.0-preview-18579-0056" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="3.0.0-preview.19080.1" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="3.0.0-preview.19080.1" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="3.0.0-preview.19080.1" />
<PackageReference Include="Microsoft.EntityFrameworkCore" Version="3.0.0-preview.19080.1" />

Add the following snippet to your csproj file:

<PropertyGroup>
  <NoWarn>$(NoWarn);NU1605</NoWarn>
</PropertyGroup>

Referencing 3.0.0 MVC libraries don't work as intended: There are several issues with referencing a 3.0.0 MVC library.

Razor pages will 404,
ApplicationParts and factories will not be discoverable
Controllers will not be discoverable

To workaround this issue do the following:

Add the helper method:

private void Add30AssemblyWorkaround(Assembly referencedAssembly, ApplicationPartManager applicationPartManager)
{
    var partFactory = ApplicationPartFactory.GetApplicationPartFactory(referencedAssembly);

    foreach (var part in partFactory.GetApplicationParts(referencedAssembly))
    {
        applicationPartManager.ApplicationParts.Add(part);
    }

    var relatedAssemblies = RelatedAssemblyAttribute.GetRelatedAssemblies(referencedAssembly, throwOnError: true);
    foreach (var assembly in relatedAssemblies)
    {
        partFactory = ApplicationPartFactory.GetApplicationPartFactory(assembly);
        foreach (var part in partFactory.GetApplicationParts(assembly))
        {
            applicationPartManager.ApplicationParts.Add(part);
        }
    }
}

Modify your services.AddMvc() call in Startup.cs:

services.AddMvc()
    .ConfigureApplicationPartManager(manager =>
    {
        var referencedAssembly = Assembly.Load("RCL");
        Add30AssemblyWorkaround(referencedAssembly, manager);
    })
    ...

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.NET Core 3.0 Preview Known Issues

ASP.NET Core

Preview 3

3.8 KiB

Raw Blame History