The configuration items used in this article correspond to POCO object ：

public class Profile
{
        public Gender Gender { get; set; }
        public int Age { get; set; }
        public ContactInfo ContactInfo { get; set; }
}

public class ContactInfo
{
        public string EmailAddress { get; set; }
        public string PhoneNo { get; set; }      
}

1、IOptionsSnapshot

In the last article we introduced IOptions and IOptionsMonitor, Here we talk about IOptionsSnapshot. Let's take a look at the following configuration file ：

{
  "foo": {
    "gender": "Male",
    "age": "18",
    "contactinfo": {
      "emailAddress": "foobar.outlook.com",
      "phoneno": "123"
    }
  },
  "bar": {
    "gender": "Female",
    "age": "20",
    "contactinfo": {
      "emailAddress": "foobar.outlook.com",
      "phoneno": "456"
    }
  }
}

Here you are 2 Configurations , The fields of configuration items are the same , But each configuration has its own name ：foo and bar. It's like a class with many students , Every student has his own attributes ( full name 、 Age etc. ).

The use of this configuration is not much different from the two introduced in the previous article , Let's take a look at the code ：

This is startup Of ConfigureServices Code in function ：

var configuration1 = new ConfigurationBuilder().AddJsonFile(path: "profile1.json", optional: false, reloadOnChange: true).Build();
            services.AddOptions().Configure<Profile>("foo", configuration1.GetSection("foo"));
            services.AddOptions().Configure<Profile>("bar", configuration1.GetSection("bar"));

This is the code to get the configuration ：

var fooProfile = _snapOptions.Get("foo");
var barProfile = _snapOptions.Get("bar");

_snapOptions Is a defined global variable ：IOptionsSnapshot<Profile> _snapOptions, Assign values to it through dependency injection .

This method actually gives the configuration a name , Then get the configuration by name .

 2、MemoryConfigurationSource

Previously, we used configuration files , Because this is the most common configuration , Let's take a look at using memory to configure .

var memorySource = new Dictionary<string, string>
            {
                ["gender"] = "Male",
                ["age"] = "20",
                ["ContactInfo:emailaddress"] = "[email protected]",
                ["ContactInfo:phoneno"] = "123"
            };

var memeoryConfig = new ConfigurationBuilder().AddInMemoryCollection(memorySource).Build();
services.AddOptions().Configure<Profile>(memeoryConfig);

gender and age yes Profile Attributes of a class , So you can assign a value directly . But the last two are ContactInfo Attributes of a class , So we need to ContactInfo Put it in front , Then use a colon to refer to the properties of this class . Note here that it must be a colon , Not commas .

The way to get the configuration is the same as before , I won't go into that here .