从 .NET 5 升级到 .NET 6 后，脚手架身份页面中的自定义 Bootstrap 4 UI 损坏

Question

I upgraded a .NET 5 blazor server app to .NET 6 and while .NET 6 apps now use Bootstrap 5 by default, I wanted to continue using Bootstrap 4, so I did not update my css or js files under wwwroot.

Most of the application UI looked the same after the upgrade except for the scaffolded Identity pages that I customized with Bootstrap 4 classes. Looking in the browser dev tools, I could see that the css being loaded for the main part of the app was Bootstrap 4 but the css being loaded for the Identity pages was Bootstrap 5 (which has breaking changes).

Answer 1

Microsoft announced the breaking change (moving from Bootstrap 4 to 5) here and gave a recommendation for those who wish to stay on Bootstrap 4 .

The simplest solution: Add the MSBuild property IdentityUIFrameworkVersion in the project ( .csproj ) file and specify Bootstrap 4:

<PropertyGroup>
  <TargetFramework>net6.0</TargetFramework>
  <IdentityUIFrameworkVersion>Bootstrap4</IdentityUIFrameworkVersion>
</PropertyGroup>