System.IO.StreamReader(Request.InputStream).ReadToEnd(); and checkbox

I'm using string data = new System.IO.StreamReader(Request.InputStream).ReadToEnd(); to read data from my View (ASP.NET MVC 4.6) and it work fine but not for the checkboxes, when I have test checkbox that is not selected data contains test=false but when i select that checkbox I get test=true&test=false why it happens? How can I get only test=true?

@Edit: And checkbox is added to view by: @Html.CheckBox()