c#动态类型，及动态对象的创建，合并2个对象，map

经常会遇到这样的情况，我们在响应客户端请求的数据的时候需要对数据进行处理，比如数据库中的数据是int型，它可能表示某个枚举，或者其它的逻辑意义（数据库这样的设计可能是从数据安全性、存储量上等角度考虑），但是客户端显示的时候需要是它具体的意义。这个时候我们的处理方式一般都是2中的，如果逻辑不复杂，且单一的话，直接修改sql语句就能处理好数据源，这个时候代码里面不需要处理什么。但是如果逻辑复稍许复杂或者判断的情况有很多分支，我们不得不从代码角度来处理了。单个对象还好，多个对象比如是个list,那就要循环对某个对象的字段进行XXX了。进而衍生出了这就出现了DTO，Arg的中间对象，当然，我个人是很喜欢这样的设计的，但是某些时候也会偷懒不想写（多半情况我直接写代码生器批量生产），比如在测试的时候，在接私活的时候，在演示的时候，只为快速呈现想要的效果 都懒得去屑，是的，你会说市面上不是有很多的map库，比如automap，tinymap，甚至json.net里面的动态特性重写，方法当然很多，但用一个大轮子来费力搞这么个小事，我觉得划不来。且轮子越来越大它要干的事越多，我可不想搞的那么复杂，嗯，就是这样，写了个。具体的代码贴到下面，如果看明白，会很方便的扩展了或修改成自己想要的效果。

using System.Dynamic;
using System.Reflection;
using System.Collections.Concurrent;

private static readonly ConcurrentDictionary
   DynamicObjectProperties = new ConcurrentDictionary();

private IDictionary ToDynamicResult(T classobj, Func injectAct)
    where T : IInjectClass, new()
{
    var type = typeof(T);
    var key = type.TypeHandle;
    var dynamicResult = new ExpandoObject() as IDictionary;

    PropertyInfo[] queryPts = null;
    DynamicObjectProperties.TryGetValue(key, out queryPts);

    if (queryPts == null)
    {
        queryPts = type.GetProperties();
        DynamicObjectProperties.TryAdd(key, queryPts);
    }

    foreach (var p in queryPts)
    {
        var attributes = p.GetCustomAttributes(typeof(IngorePropertyAttribute), true);
        var columnMapping = attributes.FirstOrDefault();
        if (columnMapping != null) continue;

        var _name = p.Name;
        var _value = p.GetValue(classobj, null);
        object _tempvalue = _value;

        if (injectAct != null) _tempvalue = injectAct.Invoke(_name, _value);

        //var value = Convert.ChangeType(value，typeof(string));  
        dynamicResult.Add(p.Name, _tempvalue);
    }

    return dynamicResult;
}

/// 

/// 支持动态输出的对象接口
/// 
public interface IInjectClass
{
}
/// 

/// 动态输出时忽略此标记的属性
/// 
public class IngorePropertyAttribute : Attribute
{
}

下面我们测试一个：

 public class kk : IInjectClass
 {
    public string aa { get; set; }
    public int bb { get; set; }
    [IngoreProperty]
    public bool cc { get; set; }
    public DateTime dd { get; set; }
 }

kk ist = new kk();
ist.aa = "aaa";
ist.bb = 123;
ist.cc = false;
ist.dd = DateTime.Now;

var tt = ToDynamicResult(ist, (k, v) =>
{
    if (k != "aa") return v;

    return v + "(改变了哦)";
});

var json = Tools.JsonUtils.JsonSerializer(tt);

json = json + "

" + Tools.JsonUtils.JsonSerializer(ToDynamicResult(
       new kk
       {
           aa = "test",
           bb = 789,
           cc = true,
           dd = DateTime.Now.AddDays(2)
       }, null));

Response.Write(json);

您可以重新构造带参数的特性或者修改 injectAct对象，改成适合自己的

下面写个测试，改成表达式树最好了，先上个码

using System;
using System.Linq;
using System.Dynamic;
using System.Reflection;
using System.Linq.Expressions;
using System.Collections.Generic;
using System.Collections.Concurrent;

namespace Tools
{
    public class Class2Map
    {
        private static readonly ConcurrentDictionary
           DynamicObjectProperties = new ConcurrentDictionary();

        private static PropertyInfo[] GetObjectProperties()
        {
            var type = typeof(T);
            var key = type.TypeHandle;
            PropertyInfo[] queryPts = null;

            DynamicObjectProperties.TryGetValue(key, out queryPts);

            if (queryPts == null)
            {
                queryPts = type.GetProperties();
                DynamicObjectProperties.TryAdd(key, queryPts);
            }

            return queryPts;
        }

        /// 

        /// 单个对象映射
        /// 
        /// 类型
        /// 实例
        /// map方法集
        /// 映射后的动态对象
        public static IDictionary DynamicResult(T source, params MapCondition[] injectAct)//where T : ICustomMap
        {
            var queryPts = GetObjectProperties();
            var dynamicResult = new ExpandoObject() as IDictionary;

            foreach (var p in queryPts)
            {
                var attributes = p.GetCustomAttributes(typeof(IngoreProperty), true);
                if (attributes.FirstOrDefault() != null) continue;

                var _name = p.Name;                     //原来是属性名
                var _value = p.GetValue(source, null);  //原来的属性值
                object _resultvalue = _value;           //最终的映射值

                if (injectAct != null)
                {
                    string _tempname = null;
                    var condition = injectAct.FirstOrDefault(x => x.Orginal == _name);
                    if (CheckChangeInfo(condition, out _tempname))
                    {
                        _resultvalue = condition.fn.Invoke(_value);
                        dynamicResult.Add(_tempname ?? _name, _resultvalue);
                        continue;
                    }
                }

                //var value = Convert.ChangeType(value，typeof(string));  
                dynamicResult.Add(_name, _resultvalue);
            }

            return dynamicResult;
        }

        /// 

        /// 合并2个对象
        /// 
        /// 对象1类型
        /// 对象2类型
        /// 对象1实例
        /// 对象2实例
        /// 合并后的动态对象
        public static IDictionary MergerObject(TSource s, TTarget t)
        {
            var targetPts = GetObjectProperties();

            PropertyInfo[] mergerPts = null;
            var _type = t.GetType();
            mergerPts = _type.Name.Contains("<>") ? _type.GetProperties() : GetObjectProperties();

            var dynamicResult = new ExpandoObject() as IDictionary;

            foreach (var p in targetPts)
            {
                var attributes = p.GetCustomAttributes(typeof(IngoreProperty), true);
                if (attributes.FirstOrDefault() != null) continue;

                dynamicResult.Add(p.Name, p.GetValue(s, null));
            }
            foreach (var p in mergerPts)
            {
                var attributes = p.GetCustomAttributes(typeof(IngoreProperty), true);
                if (attributes.FirstOrDefault() != null) continue;

                dynamicResult.Add(p.Name, p.GetValue(t, null));
            }

            return dynamicResult;
        }
        /// 

        /// 合并2个对象
        /// 
        /// 对象1类型
        /// 对象2类型
        /// 对象1实例
        /// 对象2实例
        /// 合并后的动态对象
        public static List> MergerListObject(List s, TTarget t)
        {
            var targetPts = GetObjectProperties();

            PropertyInfo[] mergerPts = null;
            var _type = t.GetType();
            mergerPts = _type.Name.Contains("<>") ? _type.GetProperties() : GetObjectProperties();

            var result = new List>();

            s.ForEach(x =>
            {
                var dynamicResult = new ExpandoObject() as IDictionary;

                foreach (var p in targetPts)
                {
                    var attributes = p.GetCustomAttributes(typeof(IngoreProperty), true);
                    if (attributes.FirstOrDefault() != null) continue;

                    dynamicResult.Add(p.Name, p.GetValue(x, null));
                }

                foreach (var p in mergerPts)
                {
                    var attributes = p.GetCustomAttributes(typeof(IngoreProperty), true);
                    if (attributes.FirstOrDefault() != null) continue;

                    dynamicResult.Add(p.Name, p.GetValue(t, null));
                }

                result.Add(dynamicResult);
            });

            return result;
        }

        private static bool CheckChangeInfo(MapCondition condition, out string name)
        {
            name = null;

            bool result = condition != null &&
                          condition.fn != null &&
                          !string.IsNullOrWhiteSpace(condition.Orginal);//&&
                        //!string.IsNullOrWhiteSpace(condition.NewName);

            if (result)
            {
                var temp = condition.NewName;
                name = (string.IsNullOrWhiteSpace(temp) || temp.Trim().Length == 0) ? null : temp;
            }

            return result;
        }
    }
}

测试一下：

List kk = new List 
{ 
    new KeyValue{key="aaa", value="111"},
    new KeyValue{key="bbb", value="222"},
    new KeyValue{key="ccc", value="333"},
    new KeyValue{key="ddd", value="444"},
};

var result = Class2Map.MergerListObject(kk, new { p = "jon test" });
var json = JsonUtils.JsonSerializer(result);

Response.Write(json);

输出如下：

[{"key":"aaa","value":"111","p":"jon test"},{"key":"bbb","value":"222","p":"jon test"},{"key":"ccc","value":"333","p":"jon test"},{"key":"ddd","value":"444","p":"jon test"}]

var result = Class2Map.MergerObject(
                new KeyValue { key = "aaa", value = "111" },
                new { p = "jon test" }
            );
var json = JsonUtils.JsonSerializer(result);

Response.Write(json);

输出如下：

{ "key": "aaa", "value": "111", "p": "jon test" }