通过备注(Attribute)为实例赋值。

今天遇到一些小问题,在使用正则表达式分析如下HTML代码

<td>姓名</td><td>王五</td>
<td>年龄</td><td>22</td>
<td>性别</td><td>男</td>

发现提取出来的内容全是配对的,并且是字符串。

姓名    王五
年龄    22
性别    男

有个实体类

class people
{
     string name;
      int      aeg;
      int      sex;
}

现在问题来了,我们应该如何赋值呢?如果每次循环,那样效率太低了,不然怎么才能找通过中文找到对应的属性呢?

经过半个小时的研究,从EnumRemarkHelper中找到启发。可以通过发射+特性的方式找到对应的属性,并为其赋值。

  public class FieldRemark : Attribute
    {
        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="remark"></param>
        public FieldRemark(string remark)
        {
            _remark = remark;
        }

        private string _remark;

        /// <summary>
        /// 备注
        /// </summary>
        public string Remark
        {
            get { return _remark; }
            set { _remark = value; }
        }

        private static Dictionary<Type, Dictionary<string, FieldInfo>> dictionary = new Dictionary<Type, Dictionary<string, FieldInfo>>();

        public static Dictionary<Type, Dictionary<string, FieldInfo>> FieldRemarkDictionary
        {
            get { return FieldRemark.dictionary; }
        }

        public static void GetFieldRemarks(object obj)
        {
            Type type = obj.GetType();
            FieldInfo[] v = type.GetFields();
            Dictionary<string, FieldInfo> temp = new Dictionary<string, FieldInfo>();
            foreach (FieldInfo v1 in v)
            {
                object[] CustomAttributes = v1.GetCustomAttributes(typeof(FieldRemark), false);
                if (CustomAttributes != null && CustomAttributes.Count() > 0)
                {
                    if (!temp.ContainsKey(((FieldRemark)CustomAttributes[0]).Remark))
                    {
                        temp.Add(((FieldRemark)CustomAttributes[0]).Remark, v1);
                    }
                }
            }
            if (temp.Count > 0)
            {
                dictionary.Add(obj.GetType(), temp);
            }
        }
    }

    public class FieldRemarkHelper
    {
        public static void SetValue(object obj, string attribute, object value)
        {
            //如果缓存里面没有内容则加载
            if (FieldRemark.FieldRemarkDictionary.Count <= 0)
            {
                FieldRemark.GetFieldRemarks(obj);
            }

            //如果没有这个类型,则初始化。
            if (!FieldRemark.FieldRemarkDictionary.ContainsKey(obj.GetType()))
            {
                FieldRemark.GetFieldRemarks(obj);
            }
            
            if (FieldRemark.FieldRemarkDictionary.ContainsKey(obj.GetType()))
            {
                Dictionary<string, FieldInfo> temp = FieldRemark.FieldRemarkDictionary[obj.GetType()];
                if (temp.ContainsKey(attribute))
                {
                    MethodInfo mi=temp[attribute].FieldType.GetMethod("Parse", new Type[] { value.GetType()});
                    if (mi != null)
                    {
                        temp[attribute].SetValue(obj, mi.Invoke(temp[attribute], new object[] { value }));
                    }
                    else
                    {
                        temp[attribute].SetValue(obj,  value );
                    }
                }
                else
                {
                    throw new Exception(string.Format("程序出现错误,{0}不存在备注为{1}的属性,无法赋值", obj.GetType().Name, attribute));
                }
            }
            else 
            {
                throw new Exception(string.Format("{0}类中并不存在带有备注的属性", obj.GetType().Name));
            }
        }
    }

使用起来就很方便了。

 public class People
    {
        [FieldRemark("姓名")]
        public string name;

        [FieldRemark("性别")]
        public int  sex;

        [FieldRemark("性别")]
        public int  age;
    }
            People peo = new People();
            FieldRemarkHelper.SetValue(peo, "姓名", "王五");
            FieldRemarkHelper.SetValue(peo, "性别", 0);
            FieldRemarkHelper.SetValue(peo, "年龄", 1);

另:如果代码有问题,请大家指出,谢谢。

原文地址:https://www.cnblogs.com/comsokey/p/2136338.html