c# 特性之模型验证数据和设置默认值

封装验证特性

public abstract class ValidationAttribute : Attribute
    {
        public ValidationAttribute()
        {
            ErrorMessage = "";
            Name = "";
        }

        /// <summary>
        /// 错误消息
        /// </summary>
        public string ErrorMessage { get; set; }
        /// <summary>
        /// 字段名称
        /// </summary>
        public string Name { get; set; }
        /// <summary>
        /// 验证过程
        /// </summary>
        /// <param name="o"></param>
        /// <returns></returns>
        public virtual bool Verify(object o)
        {
            return false;
        }

        /// <summary>
        /// 默认值
        /// </summary>
        public object DefaultValue { get; set; }
    }

错误信息实体

public class ValidResult
    {

        public ValidResult()
        {
            ValidResultDetails = new List<ValidResultDetail>();

        }

        public bool IsValid
        {
            get
            {

                return ValidResultDetails.Count() == 0;
            }
        }
        public virtual string ErrorMessage
        {
            get
            {
                string r = null;

                if (ValidResultDetails.Count() > 0)
                {

                    r = ValidResultDetails.FirstOrDefault().ErrorMessage;
                }

                return r;
            }
            set
            {
                value = ErrorMessage;


            }
        }  //错误摘要
        public List<ValidResultDetail> ValidResultDetails { get; set; }
    }
    public class ValidResultDetail
    {
        public string Name { get; set; }
        public bool IsValid
        {
            get; set;
        }
        public virtual string ErrorMessage { get; set; }
    }

验证类

public class EntifyValidator
    {
        /// <summary>
        /// 验证完所有字段
        /// </summary>
        public static ValidResult Validate(object data, params string[] ignore)
        {
            return new EntifyValidator().Verify(false, data, ignore);
        }

        /// <summary>
        ///  当有未通过的验证时，直接返回，停止验证
        /// </summary>
        public static ValidResult ValidateQuickly(object data, params string[] ignore)
        {
            return new EntifyValidator().Verify(true, data, ignore);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="quickly">验证完所有字段Or验证到未通过的立即返回</param>
        /// <param name="data">需要验证的数据</param>
        /// <param name="ignore">忽略的字段</param>
        /// <returns></returns>
        public virtual ValidResult Verify(bool quickly, object data, params string[] ignore)
        {
            ValidResult result = new ValidResult();
            List<PropertyInfo> props = data.GetType().GetProperties().Where(a => !ignore.Contains(a.Name.ToLower())).ToList();
            foreach (var item in props)
            {
                var validateattrs = item.GetCustomAttributes(typeof(ValidationAttribute), true);
                var input = item.GetValue(data, null);
                foreach (var itemattr in validateattrs)
                {
                    var attr = ((ValidationAttribute)itemattr);
                    if (attr != null)
                    {
                        attr.Name = item.Name;
                        SetDefaultValue(data, item, attr);
                        var isvalid = attr.Verify(input);
                        if (string.IsNullOrEmpty(attr.ErrorMessage)) continue;
                        if (!isvalid)
                        {
                            ValidResultDetail validResultDetail = new ValidResultDetail();
                            validResultDetail.Name = item.Name;
                            validResultDetail.ErrorMessage = string.Format(attr.ErrorMessage, item.Name);
                            validResultDetail.IsValid = false;
                            result.ValidResultDetails.Add(validResultDetail);
                            if (quickly)
                            {
                                return result;
                            }
                        }
                    }
                }
            }
            return result;
        }
        /// <summary>
        /// 设置默认值
        /// </summary>
        private void SetDefaultValue(object data, PropertyInfo item, ValidationAttribute attr)
        {
            var input = item.GetValue(data, null);
            if (attr.DefaultValue != null && input == null)//设置默认值
            {
                item.SetValue(data, attr.DefaultValue, null);
            }
            else if (attr.DefaultValue != null && input.GetType().Name == "DateTime")
            {
                if (Convert.ToDateTime(input) == DateTime.MinValue)
                {
                    item.SetValue(data, Convert.ToDateTime(attr.DefaultValue), null);
                }
            }
        }
    }

封装的简单验证特性

public class InEnumAttribute : ValidationAttribute
    {
        public InEnumAttribute()
        {
            ErrorMessage = "{0}应该在区间内";
        }

        public Type RangeType { get; set; }

        public override bool Verify(object o)
        {
            if (o == null)
            {
                return false;
            }
            var r = false;
            foreach (var item in Enum.GetValues(RangeType))
            {
                if (((int)item) == Convert.ToInt32(o))
                {
                    r = true;
                    break;
                }
            }
            return r;
        }
    }

public class NotNullAttribute : ValidationAttribute
    {
        public bool? NotNull { get; set; } = true;
        public NotNullAttribute()
        {
            ErrorMessage = "{0}必填";
        }
        public override bool Verify(object o)
        {
            if (o == null)
            {
                return false;
            }
            else if (string.IsNullOrWhiteSpace(o.ToString()))
            {
                return false;
            }
            return true;
        }
    }

    /// <summary>
    /// 默认值
    /// </summary>
    public class DValueAttribute : ValidationAttribute
    {
        public DValueAttribute()
        {

        }
    }

使用方式在要验证的实体类型加特性

  /// <summary>
        /// 转单
        /// </summary>    
        [NotNull(ErrorMessage = "转单必填")]
        public string cserviceno { get; set; }
 /// <summary>
        /// 修改时间
        /// </summary>        
        [DValue(DefaultValue = "1900-01-01 00:00:00")]
        public DateTime dlastmod { get; set; }
/// <summary>
        /// 包裹类型
        /// </summary>        
        [InEnum(ErrorMessage = "包裹类型错误", RangeType = typeof(Nitemtype))]
        public Nitemtype nitemtype { get; set; }

调用

 var r = EntifyValidator.Validate(rec);
                if (!r.IsValid)
                {
                   r.ValidResultDetails.Select(item => item.ErrorMessage);
                }