Asp.Net Core: Program does not contain a static 'Main' method suitable for an entry point

Solved a similar issue by explicitly setting the OutputType tag in my classlib.csproj file:

      <PropertyGroup>
        <TargetFramework>netcoreapp2.2</TargetFramework>
        <OutputType>Library</OutputType>
      </PropertyGroup>
  

To avoid the error of "Program does not contain a static 'Main' method suitable for an entry point" in class library, Remove emitEntryPoint from buildOptions-

  "buildOptions": {
    "emitEntryPoint": true
  },

emitEntryPoint tells the compiler whether to create a Console Application or a Library. For more info refer this post

If the Main method has an async modifier, make sure that the selected C# language version is 7.1 or higher. You can fix the issue by adding below element to the .csproj file manually. Reference

<PropertyGroup>
  <LangVersion>latest</LangVersion>
</PropertyGroup>