I downloaded VS 2017 15.7, .NET Core 2.1.2 and Blazor to try it out. It wasn't working in VS 2017 properly and thought I would try through the dotnet cli and VS Code. Instead I was met with the following error:
CSC : error CS1617: Invalid option '7.3' for /langversion.
In VS, it will run the application show "Loading..." and then nothing. Not sure if the two issues are related
dotnet --info returns the following:
.NET Command Line Tools (2.1.300-preview1-008174) Product Information: Version: 2.1.300-preview1-008174 Commit SHA-1 hash: b8df89a54f Runtime Environment: OS Name: Windows OS Version: 10.0.17666 OS Platform: Windows RID: win10-x64 Base Path: C:\Program Files\dotnet\sdk\2.1.300-preview1-008174\ Microsoft .NET Core Shared Framework Host Version : 2.1.0-preview1-26216-03 Build : f2c3216183d20416568a4bbf5bb7d153e826f153
Your should use the Preview version of VS for trying out Blazor, which is numbered 15.8.x
And install the .net core 2.1 RC. 2.1.2 will not cut it.
I had the same issue (blank screen when running the app in VS, Invalid option '7.3' from CLI) and I just needed to ugrade version of the SDK. Check this using
dotnet --info. 2.1.300-preview1 does not work, you seem to need 2.1.300-rc1 which is available from https://www.microsoft.com/net/download/all