pass dictionary to controller asp.net mvc

Question

I am wanting to pass a dictionary of type to my controller via an Ajax post. The main reason here is the post may have between 1-3 key value pai

Answer 1

JavaScript object / dictionary has to be passed as a list of key-value pairs to ASP.NET MVC controller when Dictionary<TKey, TValue> is expected. Example:

If you have a dictionary like this:

public Dictionary<string, decimal?> SomeMapping { get; set; }

then you have to use something like this in your JavaScript:

var sourceMapping = { a: 1, b: 1.5, c: null };
var SomeMapping = [];
for (var key in sourceMapping) {
    if (sourceMapping.hasOwnProperty(key)) {
        SomeMapping.push({ Key: key, Value: sourceMapping[key] });
    }
}

I've used this approach in asynchronous POST request (sent using jQuery) that had content type set to 'application/json' (this may or may not be important in your case).

Answer 2

Client (JavaScript):

var dict = new Object();
dict.Key1 = "Value1"
dict.Key2 = "Value2"

$.post('/YourController/YourAction/', dict);

NOTE: The "dict" objects gets serialized behind the scenes before being sent to your action.

Server:

public ActionResult YourAction()
{
    string postData = string.Empty;
    using (StreamReader sr = new StreamReader(Request.InputStream))
    {
        postData = sr.ReadToEnd();
    }    

    //Load post data into JObject (Newtonsoft.Json)
    JObject o = JObject.Parse(postData);

    //Extract each key/val 
    string val1 = (string)o["Key1"];

    //Do whatever....
}

Answer 3

Something like (javascript)

dict = new Object();
dict['12'] = 5;
dict['13'] = 6;
dict['1000'] = 21;
dict['9'] = 13;
dict['13'] = 48;

$.post('/client.mvc/mypostaction/', { myDictionary: dict });

You can then post the dict object to your controller using a Dictionary<int, int> as property type.

ActionResult MyPostAction(Dictionary<string, int> myDictionary)

---

edit from author's code second time:

The following works for me, when having a Dictionary<string, int> kvPairs. <int, int> isn't going to work after all.

Make your post like:

var dict = new Object();
dict['13'] = 9;
dict['14'] = 10;
dict['2'] = 5;

$.post('controller.mvc/Test', { 'kvPairs': dict }, function(obj) { $('#output').html(obj.Count); });