C# json array to List

Question

I want to populate a drop down list with a list of servers I have in a json file. So I want to retrieve the list from json and use that list to add all of the servers to my drop down. I have a simple json file with a simple array in it. In an ideal world, all I want to do is something like this:

public static IConfigurationRoot Configuration { get; set; }
public static void Main(string[] args = null)
{
    var builder = new ConfigurationBuilder()
        .AddJsonFile("appsettings.json");

    Configuration = builder.Build();
    List<string> servers = Configuration["servers"];

    foreach (string server in servers)
        {
            cboSelectServer.Items.Add(server);
        }
}

And my appsettings.json file looks like this:

{
    "servers": ["server1", "server2"]
}

The message I get is

Cannot implicitly convert type 'string' to System.Collections.Generic.List<string>

What is really confusing me is that it obviously understands Configuration["servers"] is a list because if I look at Configuration["servers:0"] I get my first server.

Thanks @PraneshJanarthanan, but ToList() isn't an option when I add .Split(',') — SkinnyPete63
– SkinnyPete63, Commented Jun 7, 2017 at 11:19
Your appsettings.json contains list of string arrays, so you set value based on that. dummy code representation: List[0] => array.Split(',').ToList() — Pranesh Janarthanan
– Pranesh Janarthanan, Commented Jun 7, 2017 at 11:33

Jamiec · Accepted Answer · 2017-06-07 11:58:56Z

1

You need to make use of the GetChildren call from a ConfigurationSection as returned by GetSection:

var builder = new ConfigurationBuilder()
    .AddJsonFile("appsettings.json");

Configuration = builder.Build();
List<string> servers = Configuration.GetSection("servers")
                                    .GetChildren()
                                    .Select(x => x.Value)
                                    .ToList()

foreach (string server in servers)
    {
        cboSelectServer.Items.Add(server);
    }

You'll need a couple of using's at the top of your file:

using Microsoft.Extensions.Configuration;
using System.Linq;

edited Jun 7, 2017 at 11:58

answered Jun 7, 2017 at 11:21

Jamiec

136k15 gold badges142 silver badges202 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

SkinnyPete63 Over a year ago

Thanks Jamie, I am no programmer, just a hack trying to get by, so please bear with me. I have added the class in, no problem, but when I add the method IOptions gets underlined and there is no quick action to tell me how to resolve it. Also, is that a method of the class, or just an additional method in Main? Finally, services (as in services.Configure etc) also gets underlined with no quick action.

Jamiec Over a year ago

@SkinnyPete63 is this in an MVC/WebApi project? And if so, are you trying to consume this config data in a controller?

SkinnyPete63 Over a year ago

No, it's just a console application.

Jamiec Over a year ago

Ah right - this is the wrong answer then. Looking again .

SkinnyPete63 Over a year ago

Awesome, exactly what I was looking for. Thanks so much for your assistance.

Collectives™ on Stack Overflow

C# json array to List

1 Answer 1

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related