How to bind dynamic cart

I assume you're having collection of items (cart items). Pass it as a model to the View. And use it something like this:

<ul class="dropdown-menu dropdown-cart" role="menu">
@{
    foreach(var item in Model)
    {
              <li>
                  <span class="item">
                    <span class="item-left">
                        <img src="@item.ProductImgURL" alt="" />
                        <span class="item-info">
                            <span>@Model.ProductName</span>
                            <span>@Model.ProductPrice $</span>
                        </span>
                    </span>
                    <span class="item-right">
                        <button class="btn btn-xs btn-danger pull-right">x</button>
                    </span>
                </span>
              </li>
    }
}
</ul>

-KR