GatewayTool/GatewayTool/Models/StringLengthAttribute.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace GatewayTool.Models
{
    public abstract class AbstractValidateAttribute : Attribute
    {
        //和接口类似，抽象方法只声明方法
        public abstract bool Validate(object objValue);
    }

    [AttributeUsage(AttributeTargets.Property)]
    public class StringLengthAttribute : AbstractValidateAttribute
    {
        //字段
        private int _Mni = 0;
        private int _Max = 0;

        public StringLengthAttribute(int min, int max)
        {
            this._Max = max;
            this._Mni = min;
        }
        public override bool Validate(object objValue)
        {
            return objValue != null
                  && objValue.ToString().Length >= this._Mni
                  && objValue.ToString().Length <= this._Max;
        }
    }

    public static class AttributeExtend
    {
        public static bool Validate<T>(this T t)
        {
            Type type = t.GetType();
            foreach (var property in type.GetProperties())//属性上查找
            {
                if (property.IsDefined(typeof(AbstractValidateAttribute), true))
                {
                    object objValue = property.GetValue(t);
                    foreach (AbstractValidateAttribute attribute in property.GetCustomAttributes(typeof(AbstractValidateAttribute), true))
                    {
                        if (!attribute.Validate(objValue))//如果成功了以后 就继续验证，否则就直接返回
                        {
                            return false;
                        }
                    }
                }
            }
            return true;
        }
    }
}