public class UserInfo
{
 [Required]
 [StringLength(10, MinimumLength = 1)]
 public string Account { get; set; }

 [Required]
 [StringLength(10, MinimumLength = 6)]
 public string Password { get; set; }
}

/// <summary>
/// 提供参数值和参数的属性值输入合法性验证
/// </summary>
static class ParameterValidator
{
 /// <summary>
 /// 类型的属性否需要验证缓存
 /// </summary>
 private static readonly ConcurrentCache<Type, bool> cache = new ConcurrentCache<Type, bool>();

 /// <summary>
 /// 返回是否需要进行属性验证
 /// </summary>
 /// <param name="instance">实例</param>
 /// <returns></returns>
 private static bool IsNeedValidateProperty(object instance)
 {
  if (instance == null)
  {
   return false;
  }

  var type = instance.GetType();
  if (type == typeof(string) || type.GetTypeInfo().IsValueType == true)
  {
   return false;
  }

  return cache.GetOrAdd(type, t => t.GetProperties().Any(p => p.CanRead && p.IsDefined(typeof(ValidationAttribute), true)));
 }

 /// <summary>
 /// 验证参数值输入合法性
 /// 验证参数的属性值输入合法性
 /// </summary>
 /// <param name="parameter">参数描述</param>
 /// <param name="validateProperty">是否验证属性值</param>
 /// <exception cref="ValidationException"></exception>
 public static void Validate(ApiParameterDescriptor parameter, bool validateProperty)
 {
  var name = parameter.Name;
  var instance = parameter.Value;

  foreach (var validation in parameter.ValidationAttributes)
  {
   validation.Validate(instance, name);
  }

  if (validateProperty == true && IsNeedValidateProperty(instance) == true)
  {
   var ctx = new ValidationContext(instance) { MemberName = name };
   Validator.ValidateObject(instance, ctx, true);
  }
 }
}

// /GET webapi/user/GetById"webapi/user/GetById/{id}")]
[BasicAuth("userName", "password")]
ITask<HttpResponseMessage> GetByIdAsync(
 [Required, StringLength(10)] string id);

public class UserInfo
{
 [Required]
 [StringLength(10, MinimumLength = 1)]
 public string Account { get; set; }

 [Required]
 [StringLength(10, MinimumLength = 6)]
 public string Password { get; set; }
}

// POST webapi/user/UpdateWithJson
// Body {"Account":"laojiu","Password":"123456"}
// Return json或xml内容
[HttpPost("webapi/user/UpdateWithJson")]
ITask<UserInfo> UpdateWithJsonAsync(
 [JsonContent("yyyy-MM-dd HH:mm:ss")] UserInfo user);

// POST webapi/user/UpdateWithJson
// Body {"Account":"laojiu","Password":"123456"}
// Return json或xml内容
[HttpPost("webapi/user/UpdateWithJson")]
ITask<UserInfo> UpdateWithJsonAsync(
 [Required][JsonContent("yyyy-MM-dd HH:mm:ss")] UserInfo user);

var config = new HttpApiConfig
{
 UseParameterPropertyValidate = false
};
var client = HttpApiClient.Create<IUserApi>(config);