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

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
}

Answer 1

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");

Answer 2

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

Answer 3

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"];

Answer 4

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;"

Answer 5

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")));

Answer 6

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.

Answer 7

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; }

Answer 8

my issue is fixed by fixing a typo

Answer 9

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.

Answer 10

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

Answer 11

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.

Answer 12

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")));
}

Answer 13

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"
}

Answer 14

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")));

Answer 15

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")));

Answer 16

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();

Answer 17

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

Answer 18

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.

Answer 19

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

Answer 20

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"
}
}

Answer 21

I had the same problem and this fixed it for me:
connStr = Configuration.GetConnectionString("DefaultConnection");
change to:
connStr = Configuration["DefaultConnection:ConnectionString"]

Answer 22

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"
},

Answer 23

Remove this line from YourProjectName.csproj file:
<Nullable>enable</Nullable>

Answer 24

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.

Answer 25

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");
});

Answer 26

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");