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

Question

I am trying to write my connection string in my appsettings.json file and bring it into my startup file but I keep getting a Value cannot be null. Parameter name: connectionString. I have been using various examples but can't seem to see this new setup with ASP.NET 1.0 Core startup class.

Appsetting.json 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
}

score 51 · Accepted Answer · edited Oct 30 '19 at 09:40

51

First of all, the

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

Is slightly different from the structure you get when you add a "Asp.NET Configuration File" in Visual Studio. When you do that you get

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

without the "Data" JavaScript Object. So that's why the extension method isn't working. It expects this structure. You can use this structure (the one with "Data") anyway and get your connection string like so:

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

Notice that you are navigating through the JavaScript object tree using : instead of .. That's due to some cross-platform issues with using the ..

If you edit out the "Data":{} you can do this :

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

Now the extension method will work. Underneath the Microsoft extensions it is the same thing as the code above.

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

edited Oct 30 '19 at 09:40

LuvForAirplanes

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answered Nov 30 '16 at 15:47

GlennSills

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You keep mentioning "App" but in the Json provided there is no "App", perhaps you mean "Data"? I'm confused. – mastazi Jul 12 '19 at 09:41
You are correct @mastazi, good catch! People have been letting that slide for a couple of years now. I have edited the post. – GlennSills Jul 15 '19 at 12:53
Thank you @GlennSills for clarifying that! – mastazi Jul 16 '19 at 02:22
There is a typo in `var connectionString = Configuration["Data::ConnectionStrings:DefaultConnection"];`. The double colon `::` should be replaced by a single colon `:`. – Marc Sigrist Oct 17 '19 at 15:10
1

Thank you! You just saved my life. I spent 2 hours wondering why my connection string for user secrets was not being picked up. Turns out you need to use this exact syntax for it to work: `dotnet user-secrets set ConnectionStrings: "value"`. – Tanveer Badar Mar 30 '20 at 11:50
Make sure your *DbContext* constructor also has: `Configuration = configuration;` – Cardi DeMonaco Jr Jan 18 '21 at 02:31

score 38 · Answer 2 · answered Jan 23 '19 at 21:53

38

I was missing the letter 's' after the ConnectionString property name in the appsettings.json when using Configuration.GetConnectionString("name")

If you want to copy

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

The method wording GetConnectionString confused me, I hovered over it and oh be hold it was looking for ConnectionStrings property name instead of ConnectionString

answered Jan 23 '19 at 21:53

StefanJM

1,533
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1

Just spend half an hour trying different kind of connection strings and this was my problem.... Thanks for the answer – Jeroen Apr 11 '20 at 15:41
1

lol, can't believe that I spent long time trying to figure out what wrong I did, and finally it's one letter missing, thank you Stefan for posting that :) – amal50 Sep 02 '20 at 09:29

Rudis · Answer 3 · 2016-11-30T09:10:28.053

4

DefaultConnection is the inner object in the json structure and it is the child of Data object.

So if you want to be exact with your config file you can use

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

edited Nov 30 '16 at 09:10

answered Nov 29 '16 at 20:20

Rudis

1,177
15
30

3

The GetSection stuff is not required. You can navigate the object tree using a ":' as a delimiter. So Configuration["Data:DefaultConnection:ConnectionString"] is equivalent. See my answer below. – GlennSills Nov 30 '16 at 18:30

score 4 · Answer 4 · answered Jan 03 '19 at 05:53

4

I had got similar error.My "appsettings.json" file was not loading because the properties of the file was Copy to Output Directory -> Do not Copy. I set that to Copy always save and rebuild.It worked.

answered Jan 03 '19 at 05:53

Ashwinee Vaishampayan

81
11

score 3 · Answer 5 · answered Nov 18 '19 at 16:25

I got this because I had a connection string with a \ in it, which needed escaping to be a \\. So my localdb connection string was causing a load error like this:

"DefaultConnection": "Server=(localdb)\myinstance;Integrated Security=true;Initial Catlog=my-localdb;"

and was fixed by making it:

"DefaultConnection": "Server=(localdb)\\myinstance;Integrated Security=true;Initial Catlog=my-localdb;"

score 2 · Answer 6 · answered Dec 04 '18 at 20:21

this is was the message that appeared me

Value cannot be null. Parameter name: connectionString

I fix it changed in the startup these lines

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

To

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

tohid badri · Answer 7 · 2019-12-03T13:49:42.747

2

in asp.net core you must add IConfiguration to startUp contractor method and assignee this Parameter to a property inherited from IConfiguration inside class

 public class Startup
{
    public Startup(IConfiguration configuration)
    {
        this.Configuration = configuration;
    }
    public IConfiguration Configuration { get; }

edited Dec 03 '19 at 13:49

answered Dec 03 '19 at 12:15

tohid badri

31
4

2

Please edit your answer to include the proposed code as text (formatted as a code block). Code posted as an image isn't useful. – Adrian Mole Dec 03 '19 at 12:44

score 2 · Answer 8 · answered Jan 29 '21 at 21:33

2

my issue is fixed by fixing a typo

answered Jan 29 '21 at 21:33

Rm558

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score 1 · Answer 9 · answered Oct 06 '19 at 22:25

1

I experienced this problem using asp.net core 3.0. The workaround fix for me is:

Instead of:

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

Use this:

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

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

answered Oct 06 '19 at 22:25

CYCLONE

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Why the double colon? What is the difference? – Matt Jun 26 '20 at 08:18
I was still facing the same issue until I found this answer. thanks – Shahzad Dec 21 '20 at 17:36

score 1 · Answer 10 · answered May 24 '20 at 12:09

1

Another mistake in my case was that I was using ConnectionString, instead ConnectionStrings (Note last 's')

answered May 24 '20 at 12:09

Satya Arya

95
6

score 1 · Answer 11 · edited Jul 04 '20 at 19:12

Maybe you can try this:

services.AddDbContext<ApplicationDbContext>(options =>
    options.UseSqlServer("DefaultConnection")
);

Then set your appsettings.json do something like this:

"ConnectionStrings:": {
    "DefaultConnection": "Server=(localdb)\\MSSQLLocalDB;Database=HOME1_DATABASE;Trusted_Connection=True;MultipleActiveResultSets=true"
},

After that, when a I add migration via the console, it succeeds.

score 1 · Answer 12 · answered Aug 14 '20 at 15:54

While using Postgres SQL the appsettings.Development.json must contain

"ConnectionStrings": {  
      "DefaultConnection": "User ID=user;Password=xxxx;Host=127.0.0.1;Port=5432;Database=abc;Pooling=true"
    }

Content in the Startup.cs file would be like

 public void ConfigureServices(IServiceCollection services)
    {
        services.AddDbContext<ApplicationDbContext>
        (p => p.UseNpgsql(Configuration.GetConnectionString("DefaultConnection")));            
    }

score 1 · Answer 13 · edited Jul 27 '21 at 10:47

1

The correct way to add connection strings into your appsetting.json file is the following:

"ConnectionStrings":{
   "DefaultConnection":"Server=localdb)\\MSSQLLocalDB;Datbase=MyShop;Trusted_Connection=true"
}

edited Jul 27 '21 at 10:47

Peter Csala

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answered Jul 26 '21 at 12:13

Hamid Hussain

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1

score 1 · Answer 14 · edited Oct 29 '21 at 10:53

I get it,it was because the name of connection string that in app settings was difference from that in the configuration that in Startup !!!
The right code of connection String Configuration in startup

// replace NAMEHERE with the name of the class that inherits from DbContext
services.AddDbContextPool <NAMEHERE> (opts => opts.UseSqlServer(Configuration.GetConnectionString("here put the same Connection string name that in appsettings")));

score 0 · Answer 15 · answered Jun 14 '19 at 13:20

I fought with the null connection string issue far too long, only to find I was doing this:

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

I was using both the ConnectionStrings: prefix AND GetConnectionString. When I removed the prefix it worked:

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

score 0 · Answer 16 · answered Sep 09 '20 at 12:40

For Postgre Db, Below worked for me

    private readonly IConfiguration _config;

    string connectionString;
    public DataBaseContext(IConfiguration config)
    {
        _config = config;
        connectionString= _config.GetValue<string>("ConnectionStrings:sampleConnection");
    }

Config file:

"ConnectionStrings": { "sampleConnection":".." }

Start up file: services.AddScoped();

score 0 · Answer 17 · answered Apr 01 '21 at 01:26

0

In my case I had two IConfiguration definitions in my Startup class. Not helpful :)

answered Apr 01 '21 at 01:26

mateoc15

509
5
18

score 0 · Answer 18 · answered Jun 11 '21 at 18:19

I had this error on the day when usin Asp.Net Core 5. I tried all above solutions with no satisfaction. Then I deleted the "ConnectionStrings" section the appsettings.json file and launched a migration. After the error, I rewrote the section and launched again the migration. All worked fine.

score 0 · Answer 19 · answered Jul 03 '21 at 09:21

Please make sure you have all you connection strings defined in the app.json. My problem was I had two different projects that added a dbContext in their services config

The identity project which made a reference to the identityDb
The persistence project that all my data access logic

I solved the issue by having both connection strings defined in the app.json

score 0 · Answer 20 · answered Apr 25 '22 at 01:23

try it, it will work for you on version 3.0.0.

public class Startup { private readonly IConfiguration configuration; public Startup(IConfiguration configuration) { this.Configuration = configuration; }

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllersWithViews();
        services.AddDbContext<DataContext>(options =>
        {
            options.UseSqlServer(Configuration.GetConnectionString("MyPortfolio"));
        });
    }

appsettings.json

"Logging": { "LogLevel": { "Default": "Information", "Microsoft": "Warning", "Microsoft.Hosting.Lifetime": "Information" } }, "AllowedHosts": "*", "ConnectionStrings": { "MyPortfolio": "Data Source=(localdbd)\MSSQLLocalDB; initail catalog=MyPortfolioDB; Integrated Security=true" } }

As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer). — Community, Apr 25 '22 at 04:07

score 0 · Answer 21 · edited May 10 '22 at 14:11

0

I had the same problem and this fixed it for me:

connStr = Configuration.GetConnectionString("DefaultConnection");

change to:

connStr = Configuration["DefaultConnection:ConnectionString"]

edited May 10 '22 at 14:11

oguz ismail

1
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answered May 07 '22 at 13:58

Parham B

1

score 0 · Answer 22 · answered Sep 19 '22 at 06:47

I am having the same error but realize to be an typo.

"ConnectionStringd": {
    "DefaultConnection":  "Server=localhost;Database=BookListRazor;Trusted_Connection=True;MutipleActiveResultSets=True"
},

the correct typing should be

"ConnectionStrings": {
    "DefaultConnection":  "Server=localhost;Database=BookListRazor;Trusted_Connection=True;MutipleActiveResultSets=True"
},

score 0 · Answer 23 · answered Oct 03 '22 at 17:36

0

Remove this line from YourProjectName.csproj file:

<Nullable>enable</Nullable>

answered Oct 03 '22 at 17:36

M Komaei

7,006
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score 0 · Answer 24 · answered Nov 17 '22 at 17:18

In my case this is a new deployment to a new server. It turns out the environment variable ASPNETCORE_ENVIRONMENT was not set, so .NET Core couldn't get the connection string from appsettings.PROD file, and thus passed null to options.UseSqlServer(connection).

Once I created a new environment variable ASPNETCORE_ENVIRONMENT and set its value to PROD, problem is solved.

score 0 · Answer 25 · answered Nov 18 '22 at 12:22

instead of using the method given below

builder.Services.AddDbContext<FullstackAPIcontext>(options => options.UseSqlServer(builder.Configuration.GetConnectionString("FullStackConnectionString")));

You can directly add the connection string after Usesqlserver .The code snippet is given below

builder.Services.AddDbContext<FullstackAPIcontext>(options =>
       {
           options.UseSqlServer("Server=myserver;Database=FullstackDb;Trusted_Connection=SSPI;Encrypt=false;TrustServerCertificate=true");
       });

score -1 · Answer 26 · answered Nov 29 '16 at 20:14

You need to change your appsetting.jsonto:

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

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

And now will be working:

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

ConnectionString must not be child of Data, as `GetConnectionString('DefaultConnection`) is an shorthand for `Configuration["ConnectionString:DefaultConnection"]` — Tseng, Nov 29 '16 at 20:47

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

26 Answers26

Instead of:

Use this:

Linked