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<T>,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<RuntimeTypeHandle, PropertyInfo[]>
DynamicObjectProperties = new ConcurrentDictionary<RuntimeTypeHandle, PropertyInfo[]>();

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

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;
}

/// <summary>
/// 支持动态输出的对象接口
/// </summary>
public interface IInjectClass
{
}
/// <summary>
/// 动态输出时忽略此标记的属性
/// </summary>
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<kk>(ist, (k, v) =>
{
if (k != "aa") return v;

return v + "(改变了哦)";
});

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

json = json + "<br /><br />" + Tools.JsonUtils.JsonSerializer(ToDynamicResult<kk>(
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<RuntimeTypeHandle, PropertyInfo[]>
DynamicObjectProperties = new ConcurrentDictionary<RuntimeTypeHandle, PropertyInfo[]>();

private static PropertyInfo[] GetObjectProperties<T>()
{
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;
}

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

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;
}

/// <summary>
/// 合并2个对象
/// </summary>
/// <typeparam name="TSource">对象1类型</typeparam>
/// <typeparam name="TTarget">对象2类型</typeparam>
/// <param name="s">对象1实例</param>
/// <param name="t">对象2实例</param>
/// <returns>合并后的动态对象</returns>
public static IDictionary<string, Object> MergerObject<TSource, TTarget>(TSource s, TTarget t)
{
var targetPts = GetObjectProperties<TSource>();

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

var dynamicResult = new ExpandoObject() as IDictionary<string, Object>;

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;
}
/// <summary>
/// 合并2个对象
/// </summary>
/// <typeparam name="TSource">对象1类型</typeparam>
/// <typeparam name="TTarget">对象2类型</typeparam>
/// <param name="s">对象1实例</param>
/// <param name="t">对象2实例</param>
/// <returns>合并后的动态对象</returns>
public static List<IDictionary<string, Object>> MergerListObject<TSource, TTarget>(List<TSource> s, TTarget t)
{
var targetPts = GetObjectProperties<TSource>();

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

var result = new List<IDictionary<string, Object>>();

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

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<KeyValue> kk = new List<KeyValue>
{
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<KeyValue, dynamic>(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<KeyValue, dynamic>(
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" }