ASP.NET 找不到 Core 6 命名连接字符串

Question

I am using .NET 6 and Entity Framework Core 6 in a new ASP.NET Core MVC web app. I have my connection string set in user-secrets. I was able to perform a

dotnet ef dbcontext scaffold Name=ConnectionStrings:someconn 

without any trouble. My model context was created. Now I want to do a simple query, but the builder in program.cs is complaining about not finding the connection.

Here I create a builder

var builder = WebApplication.CreateBuilder(args);

var currentDirectory = AppDomain.CurrentDomain.BaseDirectory;
var environmentName = builder.Environment.EnvironmentName;

builder.Configuration
    .SetBasePath(currentDirectory)
    .AddUserSecrets<Program>()
    .AddEnvironmentVariables();

var connectionString = builder.Configuration.GetConnectionString("ConnectionStrings:someconn ");

Here I place this code inside program.cs, and just before app.Run.

using (var ctx = new ModelContext())
{
    List<SomeModel> pd = ctx.SomeModel
        .Where(p => p.Id == "12345").ToList();

}

app.Run();

Error

A named connection string was used, but the name 'ConnectionStrings:someconn' was not found in the application's configuration

Answer 1

Here's a sample for reading a connection string from appsettings.json. (for simplicity I've used a sample for sqlite, which shouldn't affect they general way of reading the string.)

Hope this helps.

appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Information",
      "Microsoft.AspNetCore": "Information"
    }
  },
  "ConnectionStrings": {
    "someconn": "Data Source=some.sqlite"
  }
}

and the in Program.cs

var builder = WebApplication.CreateBuilder(args);
var connectionString = builder.Configuration.GetConnectionString("someconn")

A reason could be that the appsettings.json isn't found. Maybe check if this part of the code is needed or execute it after reading the connection string.

var builder = WebApplication.CreateBuilder(args);
var connectionString = builder.Configuration.GetConnectionString("someconn")


var currentDirectory = AppDomain.CurrentDomain.BaseDirectory;
var environmentName = builder.Environment.EnvironmentName;

builder.Configuration
    .SetBasePath(currentDirectory)//check if this is necessary
    .AddUserSecrets<Program>()
    .AddEnvironmentVariables();

Answer 2

Change below code

var connectionString = builder.Configuration.GetConnectionString("ConnectionStrings:someconn ");

to

var connectionString = builder.Configuration.GetConnectionString("someconn");

It works in my local, you can try it. Also note that there is an extra space in your code.