DynamicPlaceholderWithFluentTagBuilder.cshtml

@* Using with a basic TagBuilder *@
<div>
    @Html.Sitecore().DynamicPlaceholder("feature", 
        Html.Tag("div")
            .AddCssClass("col-sm-4")
            .GenerateId("featureCol"),
        3, 3)
</div>

@* Using with a Func<DynamicPlaceholderRenderContext, TagBuilder> *@
<div class="row">
    @Html.Sitecore().DynamicPlaceholder("feature", 
        ctx => @Html.Tag("div")
                    .AddCssClass("col-sm-" + 12 / ctx.PlaceholdersCount)
                    .GenerateId("featureCol" + ctx.Index),
        3, 4)
</div>