Denis的回答让我想到了另一个使用JsonObjects的解决方案，

头属性检查器:

Predicate<object> hasHeader = jsonObject =>
                                 ((JObject)jsonObject).OfType<JProperty>()
                                     .Any(prop => prop.Name == "header");

或许更好:

Predicate<object> hasHeader = jsonObject =>
                                 ((JObject)jsonObject).Property("header") != null;

例如:

dynamic json = JsonConvert.DeserializeObject(data);
string header = hasHeader(json) ? json.header : null;

Denis的回答让我想到了另一个使用JsonObjects的解决方案，

头属性检查器:

Predicate<object> hasHeader = jsonObject =>
                                 ((JObject)jsonObject).OfType<JProperty>()
                                     .Any(prop => prop.Name == "header");

或许更好:

Predicate<object> hasHeader = jsonObject =>
                                 ((JObject)jsonObject).Property("header") != null;

例如:

dynamic json = JsonConvert.DeserializeObject(data);
string header = hasHeader(json) ? json.header : null;

以防它能帮到别人:

如果GetDataThatLooksVerySimilarButNotTheSame()方法返回一个ExpandoObject，你也可以在检查之前将其转换为dictionary。

dynamic test = new System.Dynamic.ExpandoObject();
test.foo = "bar";

if (((IDictionary<string, object>)test).ContainsKey("foo"))
{
    Console.WriteLine(test.foo);
}

由于ExpandoObject继承了IDictionary<string对象>，您可以使用以下检查

dynamic myVariable = GetDataThatLooksVerySimilarButNotTheSame();

if (((IDictionary<string, object>)myVariable).ContainsKey("MyProperty"))    
//Do stuff

您可以创建一个实用程序方法来执行此检查，这将使代码更加清晰和可重用

The two common solutions to this include making the call and catching the RuntimeBinderException, using reflection to check for the call, or serialising to a text format and parsing from there. The problem with exceptions is that they are very slow, because when one is constructed, the current call stack is serialised. Serialising to JSON or something analogous incurs a similar penalty. This leaves us with reflection but it only works if the underlying object is actually a POCO with real members on it. If it's a dynamic wrapper around a dictionary, a COM object, or an external web service, then reflection won't help.

另一种解决方案是使用IDynamicMetaObjectProvider获取DLR看到的成员名。在下面的例子中，我使用一个静态类(Dynamic)来测试Age字段并显示它。

class Program
{
    static void Main()
    {
        dynamic x = new ExpandoObject();

        x.Name = "Damian Powell";
        x.Age = "21 (probably)";

        if (Dynamic.HasMember(x, "Age"))
        {
            Console.WriteLine("Age={0}", x.Age);
        }
    }
}

public static class Dynamic
{
    public static bool HasMember(object dynObj, string memberName)
    {
        return GetMemberNames(dynObj).Contains(memberName);
    }

    public static IEnumerable<string> GetMemberNames(object dynObj)
    {
        var metaObjProvider = dynObj as IDynamicMetaObjectProvider;

        if (null == metaObjProvider) throw new InvalidOperationException(
            "The supplied object must be a dynamic object " +
            "(i.e. it must implement IDynamicMetaObjectProvider)"
        );

        var metaObj = metaObjProvider.GetMetaObject(
            Expression.Constant(metaObjProvider)
        );

        var memberNames = metaObj.GetDynamicMemberNames();

        return memberNames;
    }
}

对我来说，这是可行的:

if (IsProperty(() => DynamicObject.MyProperty))
  ; // do stuff



delegate string GetValueDelegate();

private bool IsProperty(GetValueDelegate getValueMethod)
{
    try
    {
        //we're not interesting in the return value.
        //What we need to know is whether an exception occurred or not

        var v = getValueMethod();
        return v != null;
    }
    catch (RuntimeBinderException)
    {
        return false;
    }
    catch
    {
        return true;
    }
}