.net core application报错The required library hostfxr.dll could not be found.

.Net Core和Framework生成的程序，.Net Core需要再运行环境中应用，直接扔给其他人会报错

:\Program Files (x86)\***>.\copyfiles.exe
A fatal error occurred. The required library hostfxr.dll could not be found.
If this is a self-contained application, that library should exist in [C:\Program Files (x86)\BiMass\].
If this is a framework-dependent application, install the runtime in the global location [C:\Program Files\dotnet] or use the DOTNET_ROOT environment variable to specify the runtime location or register the runtime location in [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x64\InstallLocation].

The .NET runtime can be found at:
  - https://aka.ms/dotnet-core-applaunch?missing_runtime=true&arch=x64&rid=win10-x64&apphost_version=6.0.5

参照连接

.net core 发布单个exe 文件， 并优化缩小大小

1. 运行 build
   dotnet build
2. 创建基于x64系统的包
   dotnet publish -r win-x64 -c Release /p:PublishSingleFile=true /p:PublishTrimmed=true
   这个时候会生成win-x64文件，里面有一个publish文件夹，里面的文件就可以自带运行状态给他人使用了