是否有一种简单的方法来合并C#匿名对象

Question

假设我有两个这样的匿名对象:

var objA = new { test = "test", blah = "blah" };
var objB = new { foo = "foo", bar = "bar" };

我想将它们结合起来得到:

new { test = "test", blah = "blah", foo = "foo", bar = "bar" };

我不知道在编译时objA和objB的属性是什么.我希望这就像jquery的extend方法.

有人知道可以帮我这样做的库或.net框架类吗？

Answer 1

如果您真的在C#4.0意义上表示动态,那么您可以执行以下操作:

static dynamic Combine(dynamic item1, dynamic item2)
{
    var dictionary1 = (IDictionary<string, object>)item1;
    var dictionary2 = (IDictionary<string, object>)item2;
    var result = new ExpandoObject();
    var d = result as IDictionary<string, object>; //work with the Expando as a Dictionary

    foreach (var pair in dictionary1.Concat(dictionary2))
    {
        d[pair.Key] = pair.Value;
    }

    return result;
}

您甚至可以使用带有两个对象(不是动态的)的反射来编写一个版本并返回一个动态.

Answer 2

使用TypeDescriptor

正如评论中所提到的,Luke Foust解决方案不适用于匿名类型.强制转换为Dictionary不起作用,我建议使用TypeDescriptor.GetProperties方法构造字典:

public static dynamic CombineDynamics(object object1, object object2)
{
  IDictionary<string, object> dictionary1 = GetKeyValueMap(object1);
  IDictionary<string, object> dictionary2 = GetKeyValueMap(object2);

  var result = new ExpandoObject();

  var d = result as IDictionary<string, object>;
  foreach (var pair in dictionary1.Concat(dictionary2))
  {
    d[pair.Key] = pair.Value;
  }

  return result;
}

private static IDictionary<string, object> GetKeyValueMap(object values)
{
  if (values == null)
  {
    return new Dictionary<string, object>();
  }

  var map = values as IDictionary<string, object>;
  if (map == null)
  {
    return map;
  }

  map = new Dictionary<string, object>();
  foreach (PropertyDescriptor descriptor in TypeDescriptor.GetProperties(values))
  {
    map.Add(descriptor.Name, descriptor.GetValue(values));
  }

  return map;
}

它现在使用匿名类型:

var a = new {foo = "foo"};
var b = new {bar = "bar"};

var c = CombineDynamics(a, b);

string foobar = c.foo + c.bar;

笔记:

我的GetKeyValueMap方法基于RouteValueDictionary类(System.Web.Routing).我已经重写了它(使用ILSpy来反汇编它),因为我认为一个System.Web类与对象合并无关.