c# - 在类中从 appsetting.json 获取值

Question

我下面有一些appsetting.json

{
  "MyConfig": {
    "FolderAnnouncement": "Duyuru\\",
    "BaseMediaUrl": "D:\\YoungTalent\\YTPanel\\YTPanel\\wwwroot\\images\\"
  },
  "ConnectionStrings": {
    "MySqlCon": "Server=localhost;Database=kariyer_portal;Uid=root;Pwd=1234;",
    "MsSqlCon": "Server=localhost\\SQLEXPRESS;Database=kariyer_portal;Trusted_Connection=True;ConnectRetryCount=0"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Warning"
    }
  },
  "AllowedHosts": "*"
}

我有一个 MyConfig 类。

namespace YTPanel.Models.Model
{
    public interface ITest { string GetFolders(string param); }
    public class MyConfig: ITest
    {
        public MyConfig(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        private readonly IConfiguration Configuration;


        public string BaseMediaUrl { get; set; }
        public string FolderAnnouncement { get; set; }

        public string GetFolders(string param)
        {

            string here = Configuration["MyConfig:" + param];
            return here; 
        }
    }   
}

我想从另一个类调用这个类

MyConfig conf;
  private  string SaveAnnouncement(IFormFile file=null,string base64=null)
        {
            string path = conf.GetFolders("FolderAnnouncement");
            string imageUrl = Guid.NewGuid().ToString();
            var mediaPath = conf.GetFolders("BaseMediaUrl");
            string extension = Path.GetExtension(file.FileName);
            var imagePath = mediaPath + path + imageUrl+extension;
            if (!string.IsNullOrEmpty(base64))
            {
                byte[] bytes = Convert.FromBase64String(base64);
                File.WriteAllBytes(imagePath, bytes);  
            }
            else
            {
                using (var fileStream = new FileStream(imagePath, FileMode.Create))
                {
                    file.CopyToAsync(fileStream);
                }
            }
            return  imageUrl+extension;

        }

我在下面添加到 Startup 中的 ConfigureServices。

services.AddSingleton<ITest, MyConfig>();

我无法访问数据。我怎么解决这个问题。我想在一个类中 reacj appsetting json，我在任何我想要的类中使用这个类。

提前致谢

Answer 1

确实没有必要到处传递 IConfiguration。该框架已经内置了允许您从设置中的值绑定(bind)对象模型的功能

创建一个简单的类来保存您的配置。

public class MyConfig {
    public string BaseMediaUrl { get; set; }
    public string FolderAnnouncement { get; set; }
}

在 Startup 的 ConfigureServices 中设置你的类。

//bind object model from configuration
MyConfig myConfig = Configuration.GetSection("MyConfig").Get<MyConfig>();

//add it to services
services.AddSingleton(myConfig);

并在需要的地方注入(inject)你的强类型配置类

private readonly MyConfig conf;

//Constructor
public AnnouncementService(MyConfig config) {
    this.conf = config;
}

private async Task<string> SaveAnnouncement(IFormFile file = null, string base64 = null) {
    string path = conf.FolderAnnouncement;
    string imageUrl = Guid.NewGuid().ToString();
    var mediaPath = conf.BaseMediaUrl;
    string extension = Path.GetExtension(file.FileName);
    var imagePath = mediaPath + path + imageUrl+extension;
    if (!string.IsNullOrEmpty(base64)) {
        byte[] bytes = Convert.FromBase64String(base64);
        File.WriteAllBytes(imagePath, bytes);  
    } else {
        using (var fileStream = new FileStream(imagePath, FileMode.Create)) {
            await file.CopyToAsync(fileStream);
        }
    }
    return  imageUrl+extension;
}

请注意如何不再需要魔法字符串。您可以通过属性访问所需的配置值。

引用 Configuration in ASP.NET Core