- **Visual style in WinForms app not showing correctly when publishing with PublishReadyToRun=true**
The ReadyToRun compiler in this preview does not copy Win32 resources from the managed assembly to the compiled output binary, which causes an issue with visual styles in WinForms apps. The workaround is to skip compilation of System.Windows.Forms.dll by adding the following to the project file:
With a 3.0.100-preview5 SDK installed, and Visual Studio 16.0-preview2 or earlier, attempting to scaffold a .NET Core 3.0 project in Visual Studio will cause Visual Studio to hang indefinitely, with no indication of the problem. With a 3.0.100-preview5 SDK installed, and Visual Studio 16.0-preview3, Scaffolding will fail for all 3.0 projects.
Workaround: Uninstall 3.0.100-preview5 and install a lower version.
- **`@attribute` directive does not work in _Imports.razor**
When adding the `@attribute` directive in *_Imports.razor* the project may fail to build with the following error:
```
System.IndexOutOfRangeException : Index was outside the bounds of the array.
```
To workaround this issue add the `@attribute` to the individual .razor files instead of in *_Imports.razor*.
- **Publishing an ASP.NET Core hosted client-side Blazor app to Azure as a self-contained app fails**
Publishing an ASP.NET Core hosted client-side Blazor app to Azure as a self-contained app fails with the following error:
```
Error NETSDK1005: Assets file 'C:\Users\user\Source\Repos\WebApplication1\WebApplication1.Client\obj\project.assets.json' doesn't have a target for '.NETStandard,Version=v2.0'. Ensure that restore has run and that you have included 'netstandard2.0' in the TargetFrameworks for your project.
```
This issue will be addressed in a future release.
- **`@bind-value` on its own results in a build error**
Writing `<input @bind-value="SOMEVALUE" />` in a component results in the following error:
```
error RZ9991: The attribute names could not be inferred from bind attribute '@bind-value'. Bind attributes should be of the form'bind' or 'bind-value' along with their corresponding optional parameters like 'bind-value:event', 'bind:format' etc.
```
To work around this issue add a `@bind-value:event="SOMEEVENT"` to the input element: `<input @bind-value="SOMEVALUE" @bind-value:event="SOMEEVENT" />`.
- **Using element refs with JavaScript interop in a client-side Blazor apps fails when the IL linker is disabled**
Using element refs with JavaScript interop in a client-side Blazor apps fails when the IL linker is disabled with the following exception:
```
System.MissingMethodException: Method not found: !!0& System.Runtime.CompilerServices.Unsafe.Unbox<!0>(object)
```
To work around this issue enable the IL linker as part of the build.
- **Using the AuthorizingContent and NotAuthorizedContent parameters on Router results in a compilation error in server-side Blazor apps**
Specifying the `AuthorizingContent` or `NotAuthorizedContent` parameters on the `Router` component in a server-side Blazor app results in a compilation error.
```
error RZ9996: Unrecognized child content inside component 'Router'. The component 'Router' accepts child content through the following top-level items: 'NotFoundContent'.
- **Cancellation is not sent to the server when using the `Grpc.Net.Client` gRPC client**
Canceling a gRPC client will cancel the call on the client, but will not send a cancellation notification to the server.
If your gRPC services rely on cancellation you should continue to use the `Grpc.Core` gRPC client until preview 7. This issue will fixed in a future update.
- **`Grpc.Net.ClientFactory` does not reference all required types when used outside of ASP.NET Core**
The gRPC client factory does not reference the `Microsoft.Extensions.Http` package. If you are using the client factory you will need to include a reference to `Microsoft.Extensions.Http` in the project file.
Running a server-side Blazor app on a non-Windows platform fails with the following error:
```
System.InvalidOperationException: Could not load the embedded file manifest 'Microsoft.Extensions.FileProviders.Embedded.Manifest.xml' for assembly 'Microsoft.AspNetCore.Components.Server'.
```
This will be addressed in the next preview update.
This issue will be addressed in a future preview of Visual Studio. To workaround this issue add the `<AddRazorSupportForMvc>true</AddRazorSupportForMvc>` property to your project file.
Publishing an ASP.NET Core hosted client-side Blazor app to Azure as a self-contained app fails with the following error:
```
Error CS0006: Metadata file 'C:\Users\user\Source\Repos\WebApplication3\WebApplication3.Client\bin\Release\netstandard2.0\win-x86\WebApplication1.Client.dll' could not be found
```
To workaround this issue, add the `<AppendRuntimeIdentifierToOutputPath>false</AppendRuntimeIdentifierToOutputPath>` property to the client project file.
- **[RESOLVED] The Windows Hosting bundle doesn't exist for Preview3**: The Windows Hosting bundle contained an issue which copied the 32 bit dlls into 64 bit locations. To work aroud this issue, please install the 3.0 Preview 2 [Hosting Bundle](https://github.com/dotnet/core/blob/master/release-notes/3.0/preview/3.0.0-preview2-download.md) and run the executable on a command line with the paramaters `OPT_NO_SHAREDFX=1 OPT_NO_RUNTIME=1`. Then install the appropriate .NET and ASP.NET runtimes for preview3.
- **[RESOLVED] 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:
- **[RESOLVED] 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.
- **[RESOLVED] 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:
- **[RESOLVED] React template with authentication has a syntax error on build** in file /ClientApp/src/components/api-authorization/ApiAuthorizationConstants.js
When building or running the react template with authentication, after opening the browser, the app won't work and the following error message will be displayed.
- **[RESOLVED] Import error "Cannot find module "./components/api-authorization/Login"**: When building or running the react template with authentication, after opening the browser, the app won't work and the following error message will be displayed.
- **[RESOLVED] Runtime compilation using Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation throws an error stating "Cannot find reference assembly"**: When performing runtime Razor compilation, the application throws an error stating reference assemblies cannot be found. To workaround this, edit the project file and add this following property: