Newtonsoft.Json 转换DateTime类型为字符串时，串内部会有一个T。解决方案

使用Newtonsoft.Json 转换DateTime类型时，若使用标准转换，则字符串内会有一个T（虽然再转换成DateTime没有问题）。

若要转换成DateTime没有T，可以加上特性：

 public class TestClass
     {
         public TestClass()
         {
             Dt1 = Dt2 = new DateTime(, , , , , );
         }

         [JsonConverter(typeof(TcDateTimeConverter))]
         public DateTime Dt1 { get; set; }

         public DateTime Dt2 { get; set; }
     }

  /// <summary>
     /// DateTime Json序列化格式：yyyy-MM-dd HH:mm:ss
     /// </summary>
     public class TcFullDateTimeConverter : DateTimeConverterBase
     {
         private static IsoDateTimeConverter dtConverter = new IsoDateTimeConverter { DateTimeFormat = "yyyy-MM-dd HH:mm:ss" };

         public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
         {
             return dtConverter.ReadJson(reader, objectType, ConvertHelper.ToDateTime(existingValue), serializer);
         }

         public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
         {
             dtConverter.WriteJson(writer, ConvertHelper.ToDateTime(value), serializer);
         }
     }

     /// <summary>
     /// DateTime Json序列化格式：yyyy-MM-dd HH:mm
     /// </summary>
     public class TcDateTimeConverter : DateTimeConverterBase
     {
         private static IsoDateTimeConverter dtConverter = new IsoDateTimeConverter { DateTimeFormat = "yyyy-MM-dd HH:mm" };

         public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
         {
             return dtConverter.ReadJson(reader, objectType, ConvertHelper.ToDateTime(existingValue), serializer);
         }

         public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
         {
             dtConverter.WriteJson(writer, ConvertHelper.ToDateTime(value), serializer);
         }
     }

     /// <summary>
     /// DateTime Json序列化格式：yyyy-MM-dd
     /// </summary>
     public class TcDateConverter : DateTimeConverterBase
     {
         private static IsoDateTimeConverter dtConverter = new IsoDateTimeConverter { DateTimeFormat = "yyyy-MM-dd" };

         public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
         {
             return dtConverter.ReadJson(reader, objectType, ConvertHelper.ToDateTime(existingValue), serializer);
         }

         public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
         {
             dtConverter.WriteJson(writer, ConvertHelper.ToDateTime(value), serializer);
         }
     }

     /// <summary>
     /// DateTime Json序列化格式：HH:mm
     /// </summary>
     public class TcTimeConverter : DateTimeConverterBase
     {
         private static IsoDateTimeConverter dtConverter = new IsoDateTimeConverter { DateTimeFormat = "HH:mm" };

         public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
         {
             return dtConverter.ReadJson(reader, objectType, ConvertHelper.ToDateTime(existingValue), serializer);
         }

         public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
         {
             dtConverter.WriteJson(writer, ConvertHelper.ToDateTime(value), serializer);
         }
     }

另外，若某字段如上加上TcDateTimeConverter，再转换为带TcDateTimeConverter特性或者不带该特性的标准DateTime，都没有问题。