C# – How to add and read an appsetting.json file in a Console Application

By | 19/02/2020

In this post, we will see how to add and read an appsettings.json file in a .NET Core Console Application.
We open Visual Studio and we create a Console Application (.NET Core) project called “TestJson“:

Now, we add a file called “Parameters.json”, where we will storage a connection string for a DB and two parameters called ValueABC and ValueDEF:

{
  "Logging": {
    "LogLevel": {
      "Default": "Warning"
    }
  },
  "ConnectionStrings": {
    "DbConnection": "ExampleTestConnection"
  },
  "Parameter": {
    "ValueABC": "TestValue_ABC",
    "ValueDEF": "TestValue_DEF"
  }
}



IMPORTANT: We have to set the file’s property “Copy to Output Directory” with the value: “Copy if newer”:

Now, in order to read the Parameters.json file, we have to add, using NuGet packages, three libraries:
Microsoft.Extensions.Configuration
Microsoft.Extensions.Configuration.FileExtensions
Microsoft.Extensions.Configuration.Json

Finally, we modify Program.cs in order to read the appsetting file:

using Microsoft.Extensions.Configuration;
using System;
using System.IO;

namespace TestJson
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Starting reading file .json");

            Console.WriteLine($"ConnectioString: {GetDbConnection()}");

            Console.WriteLine($"The parameters are: {GetParameters()}");

            Console.ReadLine();
        }

        private static string GetDbConnection()
        {
            var builder = new ConfigurationBuilder()
                                .SetBasePath(Directory.GetCurrentDirectory())
                                .AddJsonFile("Parameters.json", optional: true, reloadOnChange: true);

            string strConnection = builder.Build().GetConnectionString("DbConnection");

            return strConnection;
        }

        private static string GetParameters()
        {
            var builder = new ConfigurationBuilder()
                                .SetBasePath(Directory.GetCurrentDirectory())
                                .AddJsonFile("Parameters.json", optional: true, reloadOnChange: true);

            var val1 = builder.Build().GetSection("Parameter").GetSection("ValueABC").Value;
            var val2 = builder.Build().GetSection("Parameter").GetSection("ValueDEF").Value;

            return $"The values of parameters are: {val1} and {val2}";
        }
    }
}



If we run the application, this will be the result:



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6 thoughts on “C# – How to add and read an appsetting.json file in a Console Application

  1. Peter

    Thank you,

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    Reply
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    Reply

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