Dynamic json object with numerical keys

问题

I have a json object which I converted to dynamic C# object with help of this answer. It works just fine, but trouble is that this object has numerical keys. For instance,

var jsStr = "{address:{"100": {...}}}";

So I can't wirte

dynObj.address.100

And, as I know, I can't use indexers to get this object like this

dynObj.address["100"]

Please explain to me how I can get this working.

回答1:

As far as I can see from the source code he resolves the properties through a private dictionary, so you have to use reflection to access the dictionary key, or modify his code a bit so that TryGetMember in DynamicJSONObject is the following (and use __numeric__ to get the key e.g. data.address.__numeric__100, and then avoid using __numeric__ as a key):

public override bool TryGetMember(GetMemberBinder binder, out object result)
        {
            var name = binder.Name; 
            //Code to check if key is of form __numeric__<number> so that numeric keys can be accessed
            if (binder != null && binder.Name != null && binder.Name.StartsWith("__numeric__"))
            {
                name = binder.Name.Substring(11);
            }

            if (!_dictionary.TryGetValue(name, out result))
            {
                // return null to avoid exception.  caller can check for null this way...
                result = null;
                return true;
            }

            var dictionary = result as IDictionary<string, object>;
            if (dictionary != null)
            {
                result = new DynamicJsonObject(dictionary);
                return true;
            }

            var arrayList = result as ArrayList;
            if (arrayList != null && arrayList.Count > 0)
            {
                if (arrayList[0] is IDictionary<string, object>)
                    result = new List<object>(arrayList.Cast<IDictionary<string, object>>().Select(x => new DynamicJsonObject(x)));
                else
                    result = new List<object>(arrayList.Cast<object>());
            }

            return true;
        }

回答2:

My opensource framework ImpromptuInterface has methods to call dynamic members via string name of any C# 4 dynamic object.

object tOut =Impromptu.InvokeGet(dynObj.address,"100");

I tested it with an ExpandoObject it seemed to work just fine.

回答3:

An identifier must start with a letter, underscore (_), or dollar sign ($); subsequent characters can also be digits (0-9). Because JavaScript is case sensitive, letters include the characters "A" through "Z" (uppercase) and the characters "a" through "z" (lowercase). Starting with JavaScript 1.5, ISO 8859-1 or Unicode letters (or \uXXXX Unicode escape sequences) can be used in identifiers.

Quoted from: http://en.wikipedia.org/wiki/JavaScript_syntax#Variables

Oh I am sorry mis understood the question, well here you go with a working example you can adjust to your needs:

<script>
var jsStr = {address:{'100': 'test'}};
var test = jsStr.address;
console.log(test);
alert(test[100]);        
</script>

btw key CAN be numeric (as you see in the example in the answer), only the identifiers cannot. so you have to access just like you tried. you only have to leave away the quotes for numeric keys! and your json string will not be an object without evaluation, so in this example its strictly speaking a javascript object and not json but it doesnt matter to t he subject

来源：https://stackoverflow.com/questions/6387623/dynamic-json-object-with-numerical-keys

标签

json

dynamic

key

numerical