The problem
- You want to use Chosen to snazz up your dropdowns.
- You need to store the selected values.
- You need to prefill the selected values when the page is reloaded.
Setting up chosen: Add chosen to the project. The simplest way is to use NuGet Package Manager:

- Right click solution explorer > Manager NuGet Packages > Search for "chosen" > "Install"

Once it has installed you will need to reference it in your .aspx file:


Add the chosen class to your select:
(The data-placeholder is the test shown before you make a selection)


Initialise chosen:

        $(document).ready(function () {
            //initialise the recipients field with Chosen

Reading the selected fields:

In codebehind on postback we access the select using its name, and then split the results and loop through them:

 string recipients = Request.Form["recipientselect"];
        if (recipients != null) {
            string[] recList = recipients.Split(',');
            foreach (string rec in recList) {
                // save the selected recipients

Re-loading the selections into chosen:

Probably not the best way, but it works; I've set up a basic service returning the selected recipients and then added that selection to the dropdown:

function FillSelectedRecipients() {
            var docID = $("#<%= hidDocID.ClientID %>").val()

            if (docID.length > 0) {
                    type: "POST", url: "EchoService.asmx/GetRecipients",
                    data: '{"DocID": "' + $("#<%= hidDocID.ClientID %>").val() + '"}',
                    contentType: "application/json; charset=utf-8", dataType: "json",
                    success: function (msg) {
                    error: function () { 

The recipients can be loaded in directly as json, but the chosen dropdown needs to be updated using


in order to display correctly.