c#动态类型，及动态对象的创建，合并2个对象，map

太过爱你忘了你带给我的痛 2022-08-18 11:44 220阅读 0赞

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);

![SouthEast][]  
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" }

[SouthEast]: /images/20220731/2024584763b14b2891f9f11e0a23e021.png