System.ArgumentNullException: Value cannot be null. (Parameter 'connectionString')

Question

I add appsettings.json in order to get connection string but I cannot get my connection string. Here is my code.

public class MovieTheaterDBContextFactory : IDesignTimeDbContextFactory<MovieTheaterDBContext>
{
    public MovieTheaterDBContext CreateDbContext(string []Args)
    {
        IConfigurationRoot configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
            .Build();

        var ConnectionString = configuration.GetConnectionString("MovieTheaterDBContext");
        //var ConnectionString = "Server=DESKTOPM4\\SQLEXPRESS;Database=MovieTheaterManagerment;Trusted_Connection=True;";
        var optionsBuilder = new DbContextOptionsBuilder<MovieTheaterDBContext>();
        optionsBuilder.UseSqlServer(ConnectionString);

        return new MovieTheaterDBContext(optionsBuilder.Options);
    }

   
}

appsettings.json:

{
  "ConnectionStrings":
  {
    "MovieTheaterDBContext": "Server=DESKTOPM4\\SQLEXPRESS;Database=EshopSolution;Trusted_Connection=True;"
  }
}

Update: It is my mistake, I have not set this project as startup project .So it can't find appsettings.json.

Looks like this line .SetBasePath(AppDomain.CurrentDomain.BaseDirectory) or variant: stackoverflow.com/a/60199695/495455 — Jeremy Thompson
– Jeremy Thompson, Commented Mar 12, 2021 at 1:58
Hi @Mistake,please share how do you call MovieTheaterDBContextFactory method? — Rena
– Rena, Commented Mar 12, 2021 at 6:14

Ask · Accepted Answer · 2021-03-12 06:51:24Z

0

Right click on appsettings.json file and go to the properties and change "Copy to output directory" option to "Copy always"

answered Mar 12, 2021 at 6:51

Ask

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Sterling Diaz · Accepted Answer · 2022-05-14 17:58:25Z

0

Check that your appSettings.json file is in the directory where all your projects file are located. Where the .csproj is located.

answered May 14, 2022 at 17:58

Sterling Diaz

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