Configuration.GetSection 从 appsetting.json 获取值，但 Configuration.GetSection.Bind 始终返回 null

Question

我有下面的代码，我试图将我的 appsettings.json 与我的变量绑定，并且我的变量属于类类型，其模型已根据 JSON 模式适当定义。

在调试期间，在快速观察中，我可以在 config.GetSection("TableStorageRule") 中看到我的 appsettings.json 的值，但对于 config.GetSection("TableStorageRule").Bind(tableStorageOutput) 它的 null。

var builder = new ConfigurationBuilder()
        .SetBasePath(Path.Combine(Root))
        .AddJsonFile("appsettings.json", optional: false);

var config = builder.Build();

var tableStorageOutput = new TableStorageRule();            
config.GetSection("TableStorageRule").Bind(tableStorageOutput);
var nameOfFilter = tableStorageOutput.Name;

我想知道我做错了什么？

这是我的模型类定义

public class TableStoreSettings
{
    public class AzureTableSettings
    {
        public string Account { get; set; }
        public string Key { get; set; }
        public string Table { get; set; }
    }

    public AzureTableSettings AzureTable { get; set; }

    public Uri SchemaBaseUri { get; set; }
}

public class TableStorageRule
{
    public string Name { get; set; }
    public TwisterDataFilter DataFilter { get; set; }
    public TableStoreSettings TableSettings { get; set; }
}

这是我的 Json 架构>

{  "TableStorageRule": [
  {
    "Name": "filterRule1",
    "DataFilter": {
      "DataSetType": "Settings1"
    
    },
    "TableStoreSettings": {
      "AzureTable": {
        "Account": "account1",
        "Table": "table1",
        "Key": "key1"
      },
      "SchemaBaseUri": "https://test.web.core.windows.net/"
    }
  } 
]}

Answer 1

问题出在您的 Json 中。 TableStoreSettings 需要重命名为TableSettings 以匹配类，并且您的TableStorageRule 不是规则数组。

{
  "TableStorageRule": {
    "Name": "filterRule1",
    "DataFilter": {
      "DataSetType": "Settings1"

    },
    "TableSettings": {
      "AzureTable": {
        "Account": "account1",
        "Table": "table1",
        "Key": "key1"
      },
      "SchemaBaseUri": "https://test.web.core.windows.net/"
    }
  }
  
}

如果您打算制定一系列规则，我建议您再添加一个 Top Level 类。

    public class TableStorageRules
    {
        public List<TableStorageRule> Rules { get; set; }
    }

那么你的 Json 会是这个样子

{
  "TableStorageRule": {
    "Rules": [
      
      {
        "Name": "filterRule1",
        "DataFilter":
        {
          "DataSetType": "Settings1"

        },
        "TableSettings":
        {
          "AzureTable": {
            "Account": "account1",
            "Table": "table1",
            "Key": "key1"
          },
          "SchemaBaseUri": "https://test.web.core.windows.net/"
        }

      }
    ]
  }

}

给Bind你会用这个

        var builder = new ConfigurationBuilder()
                        .SetBasePath(Path.Combine(Root))
                        .AddJsonFile("appsettings.json", optional: false);

        var config = builder.Build();

        var tableStorageOutput = new TableStorageRules();
        config.GetSection("TableStorageRule").Bind(tableStorageOutput);
        var nameOfFilter = tableStorageOutput.Rules[0].Name;