The value cannot be null. Parameter name: connectionString appsettings.json in starter

Question

I try to write my connection string in the appsettings.json file and add it to my startup file, but I keep getting the value cannot be null. Parameter Name: connectionString. I use various examples, but I don’t seem to see this new installation with the ASP.NET 1.0 Core startup class.

Apps.txt file:

{
"Data": {
"DefaultConnection": {
  "ConnectionString": "Data Source=server;Initial Catalog=dbase;Trusted_Connection=True;MultipleActiveResultSets=true"

},
"Logging": {
  "IncludeScopes": false,
  "LogLevel": {
    "Default": "Debug",
    "System": "Information",
    "Microsoft": "Information"
  }
}
}
}

Method Attempting Startup.cs

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

 public void ConfigureServices(IServiceCollection services)
    {
        var connStr = Configuration.GetConnectionString("DefaultConnection");
        System.Console.WriteLine(connStr);
        services.AddDbContext<DbContext>(options => options.UseSqlServer(connStr)); //error right here -- Null value
}

Answer 1

Primarily,

 "Data": {
"ConnectionStrings": {
  "DefaultConnection": "Data Source=server;Initial Catalog=dbase;Trusted_Connection=True;MultipleActiveResultSets=true"},
}

A bit different than the structure you get when you add the Asp.NET Configuration File in Visual Studio. When you do this, you get

"ConnectionStrings": {
  "DefaultConnection": "Data Source=server;Initial Catalog=dbase;Trusted_Connection=True;MultipleActiveResultSets=true"},

JavaScript- "". . . ( ) :

var connectionString = Configuration["Data::ConnectionStrings:DefaultConnection"];

, JavaScript, : .. ..

"": {} :

var connectionString = Configuration["ConnectionStrings:DefaultConnection"];

. , .

var config2 = Configuration.GetConnectionString("DefaultConnection");

Answer 2

' ConnectionString appsettings.json Configuration.GetConnectionString("name")

"ConnectionStrings ": {
  "SpyStore": "Server=(localdb)\\mssqllocaldb;Database=SpyStore;Trusted_Connection=True;MultipleActiveResultSets=true;"
}

GetConnectionString , , , , ConnectionStrings ConnectionString

Answer 3

DefaultConnection json Data.

, ,

var connStr = Configuration.GetSection("Data")
                           .GetSection("DefaultConnection")["ConnectionString"];

Answer 4

appsetting.json :

    {
  "Data": {
    "ConnectionStrings": {
      "DefaultConnection": "Data Source=server;Initial Catalog=dbase;Trusted_Connection=True;MultipleActiveResultSets=true"

    },
    "Logging": {
      "IncludeScopes": false,
      "LogLevel": {
        "Default": "Debug",
        "System": "Information",
        "Microsoft": "Information"
      }
    }
  }
}

:

  var connStr = Configuration.GetConnectionString("DefaultConnection");

Answer 5

,

. : connectionString

services.AddDbContext<AppIdentityDbContext>(options =>
options.UseSqlServer(
Configuration["Data:BookStoreContext:ConnectionString"]));

services.AddDbContext<AppIdentityDbContext>(options =>
options.UseSqlServer(
Configuration.GetConnectionString("BookStoreContext")));

Answer 6

. "appsettings.json" , " " → " ". , . .

Answer 7

, , :

builder.Services.AddDbContext<MlDataContext>(provider => new MlDataContext(config.GetConnectionString("ConnectionStrings:SqlConnectionString")));

ConnectionStrings: GetConnectionString. , :

builder.Services.AddDbContext<MlDataContext>(options => options.UseSqlServer(config.GetConnectionString("SqlConnectionString")));

Answer 8

, asp.net core 3.0. :

:

var connectionString = [ "ConnectionStrings: DefaultConnection"];

:

var connectionString = [ "ConnectionStrings :: DefaultConnection"];

The emphasis here is the double colon in the connection configuration.