How to read section values from appsettings.json in .NET Core

Question

I am using .NET Core 5.0. I have the below section in appsettings.json file.

"Policies": [
        {
            "name": "ApproverPolicy",
            "description": "ApproverPolicy",
            "rules": [
                {
                    "name": "abc@gmail.com",
                    "description": "abc@gmail.com"
                },
                {
                    "name": "def@gmail.com",
                    "description": "def@gmail.com"
                }
            ]
        },
        {
            "name": "RegionPolicy",
            "description": "RegionPolicy",
            "rules": [
                {
                    "name": "East US",
                    "description": "East US"
                },
                {
                    "name": "North Europe",
                    "description": "North Europe"
                }
            ]
        }
    ]

I have the below C# classes defined.

public class Policy : PolicyDefinition
{
    public IList<Rule> Rules { get; set; }
}
        
public class PolicyDefinition 
{
    public string Name { get; set; }
    public string Description { get; set; }
}
    
public class Rule
{
    public string Name { get; set; }
    public string Description { get; set; }
    public RuleStatus Status { get; set; }
    public DateTime UpdatedAt { get; set; }
    public string UpdatedBy { get; set; }
}
    
public enum RuleStatus
{
    Undefined = 0,
    Blocked = 1,
    Approved = 2,
    Rejected = 4,
    Unknown = 8
}

Iam using the below code to read the Policies section from appsettings.json file. Name and Description properties are populated as expected but "Rules" property is NULL. What changes are required to populated Rules property properly? Your help is very much appreciated.

_configuration.GetSection("Policies")
              .GetChildren()
              .ToList()
              .Select(x => new Policy
               {
                   Name = x.GetValue<string>("name"),
                   Description = x.GetValue<string>("description"),
                   Rules = x.GetValue<IList<Rule>>("rules")
                }).ToList();

The following code worked in this scenario. Thanks for all the help.

_configuration.GetSection("Policies").Get<List<Policy>>().ToList();

Can you provide json example with all fields for rule? First you can try define Status, UpdatedAt and UpdatedBy as RuleStatus? , DateTime? and string? accordingly — Ivan Khorin, Jan 28 '21 at 08:53
Does this answer your question? [Getting value from appsettings.json in .net core](https://stackoverflow.com/questions/46940710/getting-value-from-appsettings-json-in-net-core) — Ben Cottrell, Jan 28 '21 at 08:59

scottdavidwalker · Accepted Answer · 2021-01-28T09:20:39.297

5

It's easier to declare a class that matches your appsettings structure. Then you can set them in the start up and inject it into classes using IOptions.

For use in start up

 var appSettingsSection = Configuration.GetSection("Policies");
 services.Configure<List<Policy>>(appSettingsSection);
 var appSettings = appSettingsSection.Get<List<Policy>>();

then when you inject

public SomeClass(IOptions<List<Policy>> options){
     var policies = options.Value;
}

edited Jan 28 '21 at 09:20

answered Jan 28 '21 at 08:54

scottdavidwalker

1,118
1
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30

If you are going to downvote, at least put a comment as to why. – scottdavidwalker Jan 31 '21 at 15:33

score 2 · Answer 2 · answered Jan 28 '21 at 09:05

2

You cam use this code.

 var re = _configuration.GetSection("Policies")
           .GetChildren()
           .ToList()
           .Select(x => new Policy
           {
               Name = x.GetValue<string>("name"),
               Description = x.GetValue<string>("description"),
               Rules = x.GetSection("rules").Get<List<Rule>>()
    }).ToList();

Result:

answered Jan 28 '21 at 09:05

Yinqiu

6,609
1
6
14

2

Slightly shorter form based on your response. _configuration.GetSection("Policies").Get>().ToList(); – Bhanu Jan 28 '21 at 09:19

How to read section values from appsettings.json in .NET Core

2 Answers2

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