环境准备

nuget包

  • Microsoft.Extensions.Configuration
  • Microsoft.Extensions.Configuration.Binder
  • Microsoft.Extensions.Configuration.Json (当需要从Json文件添加记录时，安装此nuget包)
  • Microsoft.Extensions.Configuration.EnvironmentVariables (当需要从环境变量添加记录时，安装此nuget包)

C#开发环境

  • visual studio 2019 +
  • visual Code

示例代码

// See https://aka.ms/new-console-template for more information

using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Configuration.Json;

Console.WriteLine("Hello, World!");
ConfigurationBuilder configurationBuilder = new ConfigurationBuilder();
IConfiguration c = configurationBuilder.AddJsonFile("appsettings.json").AddEnvironmentVariables().Build();
var k = c.GetRequiredSection("Settings").Get<Settings>().KeyOne;
var n = 1;

public class NestedSettings
{
    public string Message { get; set; } = null!;
}
public class Settings
{
    public int KeyOne { get; set; }
    public bool KeyTwo { get; set; }
    public NestedSettings KeyThree { get; set; } = null!;
}

JSON 文件 (appsettings.json.ps:配置文件属性建议按下面属性设置)

image-20220906115439298 

{
    "Settings": {
        "KeyOne": 1,
        "KeyTwo": true,
        "KeyThree": {
            "Message": "Oh, that's nice..."
        }
    }
}

常见问题

如何自定义配置项目的Key

使用 [ConfigurationKeyName]属性进行设置，如下面的配置：

public class ApiConfig 
{
    [ConfigurationKeyName("endpoint")]
    public string Endpoint { get; set; }
}

配置热重载

配置热重载可以使用ChangeToken.OnChange来实现，参考微软官方文档 下面是一个例子：

// AddJsonFile("appsettings.json", false, true) 添加json时候设置重载(reloadOnChange)
ChangeToken.OnChange(
    () => GetReloadToken(), // listener to token change
    () =>
    {
        Thread.Sleep(250);
        // load config logic
        Load();
    });

参考