Retrieving flag values ​​on ASP.NET MVC postback

I am writing an ASP.NET MVC application. I am new, so I am sure it is very simple. I referred to ASP.NET MVC - how to get flag values ​​in a message , but the code is no longer available, making it next to useless.

Here is my view:

@using (@Html.BeginForm("Promote", "FPL", FormMethod.Post))
{
<div data-role="fieldcontain">
<fieldset id="PromotionInfo" name="PromotionInfo">
<legend><b>@Model.itemType Promotion Details</b></legend>
    <label for="TargetDate">Target Date: </label>
    <input type="date" id="TargetDate" data-role="datebox" data-options='{"mode": "flipbox"}' />

    <label for="EmailCC">Email cc List: </label>
    <input type="email" id="EmailCC" />

    <div  data-role="fieldcontain">
    <fieldset data-role="controlgroup">
    <legend>Choose Destination Server(s): </legend>

    @foreach (DataRow server in Model.destinationServerList.Rows)
    {
    <label for="@server.ItemArray[0]">@server.ItemArray[1]</label>  
    <input type="checkbox" name="destinationServerSID" id="@server.ItemArray[0].ToString()"  />
    }

    </fieldset>
    </div>
</fieldset>

</div>

<input type="submit" value="Submit" />
} 

And here is my controller:

    public ActionResult Promote(string id)
    {
        //Model(item) construction occurs here

        return View(item);
    }

    [HttpPost]
    public ActionResult Promote(FormCollection collection)
    {
        try
        {
            string[] test = collection.GetValues("destinationServerSID");
        }
        catch (Exception ex)
        {
            return null;
        }
    }

The variable test [] contains an array of two elements, both of which have the value "on", however, my list of elements is longer than 2 elements. It simply contains "on" for each value you select, but it does not have the value "off". I need the actual value of the checkbox (id field).