asp.net core 2.0 - Value cannot be null. Parameter name: connectionString

Question

I had the following error in package manager console when Add-Migration

Value cannot be null. Parameter name: connectionString

Answer 1

I have solved my issue by setting right base path. The problem is the migrations or anything else from different packages uses wrong path to the appsetting.json file. Not sure if it's an official issue.

I have just changed my Startup.cs as follows:

public Startup(IHostingEnvironment env)
    {
        var builder = new ConfigurationBuilder()
            .SetBasePath(env.ContentRootPath)
            .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true)
            .AddEnvironmentVariables();
        Configuration = builder.Build();
    }

After that you just need to copy your appsettings.json to the right place if it's missing there.