c# - 允许字符串 C# 中两个允许值之一的优雅方式

Question

我有一个具有以下属性的请求类

        /// <summary>
        /// First time discount flag
        /// </summary>
        [JsonProperty("firstTimeDiscountFlag")]
        public string FirstTimeDiscountFlag { get; set; }

我这样做是为了检查它是否为空并且具有允许的值

 if(string.IsNullOrWhiteSpace(request.FirstTimeDiscountFlag)
   || (request.FirstTimeDiscountFlag.ToUpper() != "Y" && request.FirstTimeDiscountFlag.ToUpper() != "N"))

有没有更好的方法来处理这个问题？

Answer 1

正确的方法是使用 JsonConverter它将把 bool 值序列化为 Y 或 N 并处理反序列化:

public class YNBoolConverter : JsonConverter
{
    public override void WriteJson(JsonWriter writer, object? value, JsonSerializer serializer)
    {
        writer.WriteValue(value switch
        {
            true => "Y",
            false => "N",
            _ => string.Empty
        });
    }

    public override object? ReadJson(JsonReader reader, Type objectType, object? existingValue, JsonSerializer serializer)
    {
        return reader.Value switch
        {
            true => true,
            "Y" => true,
            "y" => true,

            false => false,
            "N" => false,
            "n" => false,

            _ => existingValue
        };
    }

    public override bool CanConvert(Type objectType)
    {
        return objectType == typeof(string);
    }
}

您通过 JsonConverterAttribute 使用它:

{
    [JsonConverter(typeof(YNBoolConverter))]
    public bool? BoolValue { get; set; }
}

工作演示可用 here .