c# - 如何轻松合并两个具有不同数据结构的匿名对象？

Question

我想合并这两个匿名对象:

var man1 = new {
    name = new {
        first = "viet"
    },
    age = 20
};

var man2 = new {
    name = new {
        last = "vo"
    },
    address = "123 street"
};

合并成一个:

var man = new {
    name = new {
        first = "viet",
        last = "vo"
    },
    age = 20,
    address = "123 street"
};

我寻找了一个解决方案，但没有找到任何巧妙的方法。

Answer 1

将匿名对象转换为ExpandoObject这本质上是 string 的字典。键和 object值:

var man1Expando = man1.ToDynamic();
var man2Expando = man2.ToDynamic();

public static ExpandoObject ToDynamic(this object obj)
{
    IDictionary<string, object> expando = new ExpandoObject();

    foreach (var propertyInfo in obj.GetType().GetProperties())
    {
        var currentValue = propertyInfo.GetValue(obj);
        if (propertyInfo.PropertyType.IsAnonymous())
        {
            expando.Add(propertyInfo.Name, currentValue.ToDynamic());
        }
        else
        {
            expando.Add(propertyInfo.Name, currentValue);
        }
    }

    return expando as ExpandoObject;
}

我正在使用辅助扩展来确定类型是否为匿名类型:

public static bool IsAnonymous(this Type type)
{
    return type.DeclaringType is null
        && type.IsGenericType
        && type.IsSealed
        && type.IsClass
        && type.Name.Contains("Anonymous");
}

然后，将两个生成的 expando 对象合并为一个，但递归地检查嵌套的 expando 对象:

var result = MergeDictionaries(man1Expando, man2Expando, overwriteTarget: true);

public static IDictionary<string, object> MergeDictionaries(
    IDictionary<string, object> targetDictionary,
    IDictionary<string, object> sourceDictionary,
    bool overwriteTarget)
{
    foreach (var pair in sourceDictionary)
    {
        if (!targetDictionary.ContainsKey(pair.Key))
        {
            targetDictionary.Add(pair.Key, sourceDictionary[pair.Key]);
        }
        else
        {
            if (targetDictionary[pair.Key] is IDictionary<string, object> innerTargetDictionary)
            {
                if (pair.Value is IDictionary<string, object> innerSourceDictionary)
                {
                    targetDictionary[pair.Key] = MergeDictionaries(
                        innerTargetDictionary,
                        innerSourceDictionary,
                        overwriteTarget);
                }
                else
                {
                    // What to do when target propety is nested, but source is not?
                    // Who takes precedence? Target nested property or source value?
                    if (overwriteTarget)
                    {
                        // Replace target dictionary with source value.
                        targetDictionary[pair.Key] = pair.Value;
                    }
                }
            }
            else
            {
                if (pair.Value is IDictionary<string, object> innerSourceDictionary)
                {
                    // What to do when target propety is not nested, but source is?
                    // Who takes precedence? Target value or source nested value?
                    if (overwriteTarget)
                    {
                        // Replace target value with source dictionary.
                        targetDictionary[pair.Key] = innerSourceDictionary;
                    }
                }
                else
                {
                    // Both target and source are not nested.
                    // Who takes precedence? Target value or source value?
                    if (overwriteTarget)
                    {
                        // Replace target value with source value.
                        targetDictionary[pair.Key] = pair.Value;
                    }
                }
            }
        }
    }

    return targetDictionary;
}

overwriteTarget参数决定合并时哪个对象优先。

使用代码:

var man1 = new
{
    name = new
    {
        first = "viet",
    },
    age = 20,
};

var man2 = new
{
    name = new
    {
        last = "vo",
    },
    address = "123 street",
};

var man1Expando = man1.ToDynamic();
var man2Expando = man2.ToDynamic();

dynamic result = MergeDictionaries(man1Expando, man2Expando, overwriteTarget: true);

Console.WriteLine(JsonConvert.SerializeObject(result, Formatting.Indented));

结果:

{
  "name": {
    "first": "viet",
    "last": "vo"
  },
  "age": 20,
  "address": "123 street"
}

注意我是如何将结果分配给 dynamic 的.让编译器分配类型将使您得到显示为 IDictionary<string, object> 的 expando 对象。 .使用字典表示，您不能像访问匿名对象那样访问属性:

var result = MergeDictionaries(man1Expando, man2Expando, overwriteTarget: true);

result.name; // ERROR

这就是为什么 dynamic .与 dynamic您正在丢失编译时检查，但将两个匿名对象合并为一个。你必须自己判断它是否适合你。