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Accepted
JoseMgz_Ux
Asked: 2022-07-12 07:54:27 +0800 CST 2022-07-12 07:54:27 +0800 CST

C# - Value cannot be null ('connectionString' parameter) .NET 6

  • 772

I use .Net 6 and when I want to run my first migration I get this error:

The value cannot be null. ('connectionString' parameter)

My appsettings.json

    {
  "Logging": {
    "ConnectionStrings": {
      "DefaultConnection": "Data Source=MSI;Initial Catalog=tiendalibro;Integrated Security=True"
    },
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  
  "AllowedHosts": "*"
}

And the following is my method in Program.cs

builder.Services.AddDbContext<ContextoLibreria>(options => options.UseSqlServer("DefaultConnection"));
c#

2 Answers

  1. Best Answer

    Try overriding this method:

    builder.Services.AddDbContext<ContextoLibreria>(options => options.UseSqlServer("DefaultConnection"));

    For this one:

    builder.Services.AddDbContext<ContextoLibreria>(options => options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

    On the other hand, I also see that you are putting the connection string inside the logging, try putting it below the AllowedHosts: "*":

         {
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  
  "AllowedHosts": "*",
  "ConnectionStrings": {
      "DefaultConnection": "Data Source=MSI;Initial Catalog=tiendalibro;Integrated Security=True"
    },
}
    • 2

  2. It is because you have misconfigured your appsettings.json

    {
  "ConnectionStrings": {
    "DefaultConnection": "Data Source=MSI;Initial Catalog=tiendalibro;Integrated Security=True"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*"
}

    and on Program.csfire your connection

    builder.Services.AddDbContext<ContextoLibreria>(options =>
{
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection"));
});
    • 2