In c# convert anonymous type into key/value array?

Question

I have the following anonymous type:

new {data1 = \"test1\", data2 = \"sam\", data3 = \"bob\"}

I need a method that will take this in, and

Answer 1

Building on @GWB's suggestion of using a RouteValueDictionary, I wrote this recursive function to support nested anonymous types, prefixing those nested parameters by their parents' keys.

public static string EncodeHtmlRequestBody(object data, string parent = null) {
    var keyValuePairs = new List<string>();
    var dict = new RouteValueDictionary(data);

    foreach (var pair in dict) {
        string key = parent == null ? pair.Key : parent + "." + pair.Key;
        var type = pair.Value.GetType();
        if (type.IsPrimitive || type == typeof(decimal) || type == typeof(string)) {
            keyValuePairs.Add(key + "=" + Uri.EscapeDataString((string)pair.Value).Replace("%20", "+"));
        } else {
            keyValuePairs.Add(EncodeHtmlRequestBody(pair.Value, key));
        }
    }

    return String.Join("&", keyValuePairs);
}

Example usage:

var data = new {
    apiOperation = "AUTHORIZE",
    order = new {
        id = "order123",
        amount = "101.00",
        currency = "AUD"
    },
    transaction = new {
        id = "transaction123"
    },
    sourceOfFunds = new {
        type = "CARD",
        provided = new {
            card = new {
                expiry = new {
                    month = "1",
                    year = "20"
                },
                nameOnCard = "John Smith",
                number = "4444333322221111",
                securityCode = "123"
            }
        }
    }
};

string encodedData = EncodeHtmlRequestBody(data);

encodedData becomes:

"apiOperation=AUTHORIZE&order.id=order123&order.amount=101.00&order.currency=AUD&transaction.id=transaction123&sourceOfFunds.type=CARD&sourceOfFunds.provided.card.expiry.month=1&sourceOfFunds.provided.card.expiry.year=20&sourceOfFunds.provided.card.nameOnCard=John+Smith&sourceOfFunds.provided.card.number=4444333322221111&sourceOfFunds.provided.card.securityCode=123"

Hope this helps someone else in a similar situation.

Edit: As DrewG pointed out, this doesn't support arrays. To properly implement support for arbitrarily nested arrays with anonymous types would be non-trivial, and as none of the APIs I've used have accepted arrays either (I'm not sure there's even a standardised way of serialising them with form encoding), I'll leave that to you folks if you need to support them.

Answer 2

There is a built-in method of converting anonymous objects to dictionaries:

HtmlHelper.AnonymousObjectToHtmlAttributes(yourObj)

It also returns RouteValueDictionary. Note that it's static

Answer 3

It is too late but anyway I would add this for a more robust solution. The ones I see here have some kind of problems (like they wouldn't work right with say DateTime). For that reason, I suggest first converting to a json (Newtonsoft Json.Net):

var data = new {data1 = "test1", data2 = "sam", data3 = "bob"};

var result = string.Join("&",
            JsonConvert.DeserializeObject<Dictionary<string, string>>(
            JsonConvert.SerializeObject(data))
            .Select(x => $"{x.Key}={x.Value}")
        );