I am converting an object to JSON using JavaScriptSerializer and I can see this JSON output in server code:
[{\"UserId\":1,\"UserName\":\"Admin\"}]
Why are you doing that? Why not just return a JsonResult?
public ActionResult MyMethod()
{
List list = new List() {
new ListItem() { UserId = "1", UserName = "Admin" },
new ListItem() { UserId = "2", UserName = "JohnDoe" },
new ListItem() { UserId = "3", UserName = "JaneDoe" }};
return this.Json(list);
}