Adding a Dynamic form fields in MVC Asp.Net

I'm trying to add and remove form fields in MVC Asp.Net. I've followed this tutorial of dynamic adding and removing form fields.

I'm having a problem only this part of code. In below code it only adds a textbox.

if(x < max_fields){ //max input box allowed
        x++; //text box increment
        $(wrapper).append('<div><input type="text" name="mytext[]"/><a href="#" class="remove_field">Remove</a></div>'); //add input box
    }
});

but I want to add 2 dropdownlists and 1 textbox by using MVC helpers not html codes.

I've 2 dropdownlist, Sizes and Colors and 1 textbox for Quantity. Dropdownlists are populating values from DB.

<div class="form-group">
    <div class="row">
        <div class="input_fields_wrap">
            <button class="add_field_button">Add More Fields</button>
            <div class="col-md-2">
                @Html.DropDownList("ProductSizeVariantId", null, "Size", new { @class = "control-label" })
            </div>
            <div class="col-md-2">
                @Html.DropDownList("ProductSizeVariantValueId", null, "Select Size", new { @class = "control-label" })
            </div>
            <div class="col-md-2">
                @Html.DropDownList("ProductColorVariantId", null, "Select Color", new { @class = "control-label" })
            </div>
            <div class="col-md-2">
                @Html.TextBoxFor(x => x.Stock, new { @placeholder = "Quantity", @class = "form-control" })
            </div>
         </div>
    </div>
</div>

here is what i've tried

$(wrapper).append('<div><div class="col-md-2">@Html.DropDownList("ProductSizeVariantId", null, "Size", new { @class = "control-label" })</div><div class="col-md-2">@Html.DropDownList("ProductSizeVariantValueId", null, "Select Size", new { @class = "control-label" })</div><div class="col-md-2">@Html.DropDownList("ProductColorVariantId", null, "Select Color", new { @class = "control-label" })</div><div class="col-md-2">@Html.TextBoxFor(x => x.Stock, new { @placeholder = "Quantity", @class = "form-control" })</div><a href="#" class="remove_field">Remove</a></div>'); //add input box

after adding above code, when I click AddMore button, it reloads the page.