C# JSON.NET反序列化程序返回Null

编辑：它与try/catch return null语句无关。我对它进行了调试和观看，并确保它不会进入捕捉区。我甚至把它注释掉了，没有用

我为我的应用程序构建一个配置管理器已经很累了。本质上，我有一些变量需要存储在JSON文件中，并在应用程序启动期间读取，以便知道某些值

对于其中一些配置变量，我将允许用户覆盖默认值，因此如果用户密钥具有非空字符串，我将使用该字符串。如果没有用户密钥或存在空字符串，我将使用默认值。为了满足这个需求，我编写了AllowUserConfig和CoalesceUserDefault方法来处理这个问题

此时，我在下面有一个JSON文件。我复制了数据并作为一个类JSONConfig粘贴到VisualStudio中。然后，我有一个执行实际工作的ConfigManager文件，我的program.cs调用ConfigManager以使用反序列化ConfigVariables方法读取位于正确位置的配置文件，并从中创建JSONConfig对象

话虽如此，DeserializeConfigVariables中的JSONConfig对象在configVariables=serializer.DeserializejsonReader；行上返回为null；。有什么我不知道的吗。每件事我都检查了一百遍，看不出我做错了什么

任何和所有的帮助都将不胜感激

这是我的JSON：

{
  "format": {
     "date": {
        "default": "yyyyMMdd",
        "user": ""
     },
     "month_year": {
        "default": "MM_YYYY",
        "user": ""
     }
  },
  "placeholders": {
     "current_date": "{date}",
     "month_year": "{month_year}",
     "last_monday": "{prev_monday}",
     "next_monday": "{next_monday}"
  },
  "resource_locations": {
     "directories": {
        "root_working": {
           "default": "C:\\ALL",
           "user": ""
        },
        "exports": {
           "default": "C:\\ALL\\Exports",
           "user": ""
        },
        "completed_exports": {
           "default": "C:\\ALL\\Done",
           "user": ""
        },
        "archived": {
           "default": "C:\\ALL\\Archives",
           "user": ""
        }
     },
     "compression": {
        "filename": {
           "default": "{next_monday}_daily_{date}.zip",
           "user": ""
        }
     },
     "logging": {
        "directory": "logs",
        "process_filename": "activity_log_{month_year}.log",
        "process_error_filename": "errors.log",
        "system_error_filename": "sys_errors.log"
     }
  }
}

这是通过在Visual Studio中将JSON复制和粘贴为类而创建的JSONConfig类I：

using System;
using Newtonsoft.Json;

namespace Config
{

   public class JSONConfig
   {
       public RootObject ConfigVariables { get; set; }
   }

   public class RootObject
   {
       public Format format { get; set; }
       public Placeholders placeholders { get; set; }
       public Resource_Locations resource_locations { get; set; }
   }

   public class Format
   {
       public Date date { get; set; }
       public Month_Year month_year { get; set; }
   }

   public class Date
   {
       public string _default { get; set; }
       public string user { get; set; }
   }

   public class Month_Year
   {
       public string _default { get; set; }
       public string user { get; set; }
   }

   public class Placeholders
   {
       public string current_date { get; set; }
       public string month_year { get; set; }
       public string last_monday { get; set; }
       public string next_monday { get; set; }
   }

   public class Resource_Locations
   {
       public Directories directories { get; set; }
       public Compression compression { get; set; }
       public Logging logging { get; set; }
   }

   public class Directories
   {
       public Root_Working root_working { get; set; }
       public Exports exports { get; set; }
       public Completed_Exports completed_exports { get; set; }
       public Archived archived { get; set; }
   }

   public class Root_Working
   {
       public string _default { get; set; }
       public string user { get; set; }
   }

   public class Exports
   {
       public string _default { get; set; }
       public string user { get; set; }
   }

   public class Completed_Exports
   {
       public string _default { get; set; }
       public string user { get; set; }
   }

   public class Archived
   {
       public string _default { get; set; }
       public string user { get; set; }
   }


   public class Compression
   {
       public Filename filename { get; set; }
   }

   public class Filename
   {
       public string _default { get; set; }
       public string user { get; set; }
   }


   public class Logging
   {
       public string directory { get; set; }
       public string process_filename { get; set; }
       public string process_error_filename { get; set; }
       public string system_error_filename { get; set; }
   }


}

然后，在我的ConfigManager文件中，我有以下内容：

using System;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using System.Xml.Linq;
using Newtonsoft.Json;

namespace Config
{
   static class ConfigManager
   {
       // Assumes parent directory is bin.  Assumes config is sibling to bin.
       private static string _initialConfig = @"config\config.json";
       public static string ConfigPath() => Path.Combine(GetRootAppDir(), _initialConfig);


       public static string Parent(string directory)
       {
           string parentDirectory = Directory.GetParent(directory).FullName;
           return parentDirectory;
       }

       public static string GetRootAppDir()
       {
           return Parent(Parent(Directory.GetCurrentDirectory()));
       }

       public static JSONConfig DeserializeConfigVariables()
       {
           try
           {
               var configVariables = new JSONConfig();
               var serializer = new JsonSerializer();
               Console.WriteLine($"Config Path: {ConfigPath()}"); //testing
               using (var reader = new StreamReader(ConfigPath()))
               using (var jsonReader = new JsonTextReader(reader))
               {
                   configVariables = serializer.Deserialize<JSONConfig>(jsonReader);
               }

               return configVariables;
           }
           catch (System.IO.DirectoryNotFoundException ex)
           {
               Console.WriteLine(ex.Message);
               return null;
           }

       }
       public static bool AllowUserConfig(object configVariable)
       {
           string userFieldName = "user";
           var objType = configVariable.GetType();
           return objType.GetMethod(userFieldName) != null;
       }

       public static string CoalesceUserDefault(dynamic configVariable)
       {
           if (AllowUserConfig(configVariable))
           {
               if (!(String.IsNullOrEmpty(configVariable.user)))
               {
                   return configVariable.user;
               }
           }
           return configVariable._default;
       }

   }
}

希望对你有帮助

您可以添加您的jsonfile.json文件 e、 g.：-

yourjsonfile.json

另一个jsonfile.json

确保yourjsonfile.json和另一个jsonfile.json文件属性将Copy To Output Directory设置为始终复制

从yourjsonfile.json和其他类似的jsonfile.json文件中查找值-

var builder = new ConfigurationBuilder()
    .SetBasePath(Directory.GetCurrentDirectory())
    .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);

    IConfiguration configuration = builder.Build();

    string GetValue1 = configuration.GetSection("key1").Value;
    string GetValue2 = configuration.GetSection("key2").Value;

     var builder1 = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile(configuration.GetConnectionString("$ref").Replace("#", ""), optional: true, reloadOnChange: true);
    IConfiguration configuration1 = builder1.Build();

    GetValue2 = (configuration1.GetSection("key2").Value) != null ? configuration1.GetSection("key2").Value : GetValue2;

---

谢谢

您的Json在根目录中不包含名为ConfigVariable的属性，该属性是在类JSONConfig中定义的，您正试图反序列化的类型

如果您检查Json，它适合RootObject的定义。您应该将类反序列化为RootObject的实例。如果您想将配置存储在JsonConfig的实例中，可以将其分配给JsonConfig实例的ConfigVariable属性

configVariables.ConfigVariables  = serializer.Deserialize<RootObject>(jsonReader);

---

您需要将json反序列化为RootObject，而不是JSONConfig

推荐

将反序列化JSON的方法也更改为更简单的过程

public static RootObject DeserializeConfigVariables()
{
    return JsonConvert.DeserializeObject<RootObject>(File.ReadAllLines(ConfigPath()));
}

---

Json文件与用于反序列化它的对象结构不对应。 JsonConfig文件包含ConfigVariables属性，但json文件包含格式、占位符、资源位置属性，这些属性应位于第二级。 尝试按以下方式更新配置文件：

{

  "ConfigVariables": {
    "format": {
      "date": {
        "default": "yyyyMMdd",
        "user": ""
      },
      "month_year": {
        "default": "MM_YYYY",
        "user": ""
      }
    },
    "placeholders": {
      "current_date": "{date}",
      "month_year": "{month_year}",
      "last_monday": "{prev_monday}",
      "next_monday": "{next_monday}"
    },
    "resource_locations": {
      "directories": {
        "root_working": {
          "default": "C:\\ALL",
          "user": ""
        },
        "exports": {
          "default": "C:\\ALL\\Exports",
          "user": ""
        },
        "completed_exports": {
          "default": "C:\\ALL\\Done",
          "user": ""
        },
        "archived": {
          "default": "C:\\ALL\\Archives",
          "user": ""
        }
      },
      "compression": {
        "filename": {
          "default": "{next_monday}_daily_{date}.zip",
          "user": ""
        }
      },
      "logging": {
        "directory": "logs",
        "process_filename": "activity_log_{month_year}.log",
        "process_error_filename": "errors.log",
        "system_error_filename": "sys_errors.log"
      }
    }
  }
}

它会解决你的问题。 顺便说一句，正如我看到的，您在配置对象中以json样式命名了属性。例如，资源位置最好以常规方式命名属性，并添加JsonProperty属性以正确映射。 e、 g

---

非常感谢你！我明白我现在做错了什么。谢谢，谢谢。我还不太明白这一点，但我会看看我是否可以找到如何使用它，如果它将更有效地为我的应用程序。谢谢。@Yijafe如果您想在应用程序中全局使用这些JSON值，请使用我的代码，否则请使用此代码-serializer.DeserializejsonValue；非常感谢。我没有编辑json文件，而是引用了rootobject。非常感谢。另外，关于类名，这是VisualStudio默认创建它们的方式。我将看看是否有一种方法，使他们帕斯卡案件自动。我刚贴了一个小样本。我删除了更多的类和JSON对象，因此手动更新它们需要一些时间。谢谢，这就解决了。非常感谢你的帮助！

configVariables = serializer.Deserialize<RootObject>(jsonReader);

{ "ConfigVariables" :
 {
   "format": {
      "date": {
         "default": "yyyyMMdd",
         "user": ""
 ...

public static RootObject DeserializeConfigVariables()
{
    return JsonConvert.DeserializeObject<RootObject>(File.ReadAllLines(ConfigPath()));
}

{

  "ConfigVariables": {
    "format": {
      "date": {
        "default": "yyyyMMdd",
        "user": ""
      },
      "month_year": {
        "default": "MM_YYYY",
        "user": ""
      }
    },
    "placeholders": {
      "current_date": "{date}",
      "month_year": "{month_year}",
      "last_monday": "{prev_monday}",
      "next_monday": "{next_monday}"
    },
    "resource_locations": {
      "directories": {
        "root_working": {
          "default": "C:\\ALL",
          "user": ""
        },
        "exports": {
          "default": "C:\\ALL\\Exports",
          "user": ""
        },
        "completed_exports": {
          "default": "C:\\ALL\\Done",
          "user": ""
        },
        "archived": {
          "default": "C:\\ALL\\Archives",
          "user": ""
        }
      },
      "compression": {
        "filename": {
          "default": "{next_monday}_daily_{date}.zip",
          "user": ""
        }
      },
      "logging": {
        "directory": "logs",
        "process_filename": "activity_log_{month_year}.log",
        "process_error_filename": "errors.log",
        "system_error_filename": "sys_errors.log"
      }
    }
  }
}

[JsonProperty('resource_locations')]
public ResourceLocations ResouceLocations { get; set; }