c# 动态更新配置文件

在.Net Framework版本可以使用ConfigurationManager
通常是指app.config或web.config

命名空间
System.Configuration下的ConfigurationManager

private void UpdateConfig(string key,string value)
{
    Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
    config.AppSettings.Settings[key].Value = value;
    config.Save(ConfigurationSaveMode.Full);
    //加载到内存中
    ConfigurationManager.RefreshSection("appSettings");
}

.Net Core之后ConfigurationManager不在标准命名空间内，可以使用IConfiguration

命名空间
using Microsoft.Extensions.Configuration;
public static class ConfigHelper
{
    private static IConfiguration _configuration;
    public static IConfiguration Configuration
    {
        get
        {
            _configuration ??= new ConfigurationBuilder()
                    .SetBasePath(Directory.GetCurrentDirectory())
                    .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
                    .Build();//optional标识该配置是否是必须的，reloadOnChange标识是否实时加载修改，用程序改的好像不太生效
            return _configuration;
        }
    }

    public static string? GetValue(string key)
    {
        return Configuration[key];
    }

    public static void SetValue(string key, string value)
    {
        Configuration[key] = value;
    }

    public static void SaveChanges()
    {
        var configPath = Path.Combine(Directory.GetCurrentDirectory(), "appsettings.json");
        var jsonConfig = File.ReadAllText(configPath);

        var jObject = JsonConvert.DeserializeObject(jsonConfig);
        if (jObject == null)
            return;
        foreach(var item in Configuration.AsEnumerable())
		{
    		if (jObject.TryGetValue(item.Key, out _))
    		{
        		jObject[item.Key] = item.Value;
    		}
		}
        File.WriteAllText(configPath, JsonConvert.SerializeObject(jObject));
    }
}