ContainerAndRowContentAreaRenderer.cs

[ServiceConfiguration(typeof(ContentAreaRenderer), Lifecycle = ServiceInstanceScope.Singleton)]
public class ContainerAndRowContentAreaRenderer : ContentAreaRenderer
{
    // Number of columns in site grid
    protected const int NumberOfGridColumns = 12;

    // TagBuilder for the current container div.
    protected TagBuilder CurrentContainer;

    // TagBuilder for the current row div.
    protected TagBuilder CurrentRow;

    // To keep track of the current container.
    protected bool IsContainerOpen;

    // To keep track of the current row.
    protected bool IsRowOpen;

    // Current column counter for each row
    protected int CurrentColumn;

    public ContainerAndRowContentAreaRenderer(IContentRenderer contentRenderer, TemplateResolver templateResolver, ContentFragmentAttributeAssembler attributeAssembler, IContentRepository contentRepository, IContentAreaLoader contentAreaLoader) : base(contentRenderer, templateResolver, attributeAssembler, contentRepository, contentAreaLoader)
    {
    }

	protected virtual string GetContentAreaItemCssClass(HtmlHelper html, ContentAreaItem contentAreaItem, string templateTag)
	{
	    var baseClass = base.GetContentAreaItemCssClass(html, contentAreaItem);

	    // Allow developer to override by passing ChildrenCssClass in ViewData.
	    if (string.IsNullOrEmpty(baseClass) == false)
	    {
	        return baseClass;
	    }

	    return string.Format("block {0}", GetDisplayOptionCssClass(templateTag));
	}

	protected override string GetContentAreaItemTemplateTag(HtmlHelper html, ContentAreaItem contentAreaItem)
	{
	    var templateTag = base.GetContentAreaItemTemplateTag(html, contentAreaItem);

	    if (string.IsNullOrWhiteSpace(templateTag))
	    {
	        // Default to full width.
	        return SiteDisplayOptions.FullWidth;
	    }

	    return templateTag;
	}

	protected virtual string GetDisplayOptionCssClass(string templateTag)
	{
	    switch (templateTag)
	    {
	        case SiteDisplayOptions.FullWidth:
	            return "full";
	        case SiteDisplayOptions.TwoThirdsWidth:
	            return "two-thirds";
	        case SiteDisplayOptions.HalfWidth:
	            return "one-half";
	        case SiteDisplayOptions.OneThirdWidth:
	            return "one-third";
	        case SiteDisplayOptions.Hero:
	            return "hero";
	        default:
	            return templateTag;
	    }
	}

	protected virtual int GetNumberOfGridColumns(string templateTag)
	{
	    switch (templateTag)
	    {
	        case SiteDisplayOptions.TwoThirdsWidth:
	            return 8;
	        case SiteDisplayOptions.HalfWidth:
	            return 6;
	        case SiteDisplayOptions.OneThirdWidth:
	            return 4;
	        default:
	            return 12;
	    }
	}

	protected override void RenderContentAreaItems(HtmlHelper html, IEnumerable<ContentAreaItem> contentAreaItems)
	{
	    CurrentColumn = 0;
	    IsContainerOpen = false;
	    IsRowOpen = false;

	    foreach (ContentAreaItem contentAreaItem in contentAreaItems)
	    {
	        string templateTag = this.GetContentAreaItemTemplateTag(html, contentAreaItem);
	        bool isHeroContentAreaItem = this.IsHeroTag(templateTag);

	        if (isHeroContentAreaItem)
	            this.BeforeRenderHeroContentAreaItem(html, contentAreaItem);
	        else
	            this.BeforeRenderNormalContentAreaItem(html, contentAreaItem, templateTag);

	        using (html.BeginRenderingTag(templateTag))
	        {
	            this.RenderContentAreaItem(html, contentAreaItem, templateTag, this.GetContentAreaItemHtmlTag(html, contentAreaItem), this.GetContentAreaItemCssClass(html, contentAreaItem, templateTag));
	        }
	    }

	    // Close last row if open.
	    if (IsRowOpen)
	        EndRow(html);

	    // Close last container if open.
	    if (IsContainerOpen)
	        EndContainer(html);
	}

	protected virtual void BeforeRenderHeroContentAreaItem(HtmlHelper html, ContentAreaItem contentAreaItem)
	{
	    // Make sure to close row and container if open. We don't want to wrap hero blocks.
	    if (IsRowOpen)
	        EndRow(html);

	    if (IsContainerOpen)
	        EndContainer(html);
	}

	protected virtual void BeforeRenderNormalContentAreaItem(HtmlHelper html, ContentAreaItem contentAreaItem, string templateTag)
	{
	    int itemColumns = this.GetNumberOfGridColumns(templateTag);
	    CurrentColumn += itemColumns;
	    bool fitsInRow = CurrentColumn <= NumberOfGridColumns;

	    // Open container if not already open.
	    if (IsContainerOpen == false)
	        StartContainer(html);

	    if (fitsInRow == false || IsRowOpen == false)
	    {
	        // Make sure to close row if open.
	        if (IsRowOpen)
	            EndRow(html);

	        // Start on a new row.
	        StartRow(html);

	        // Set current column
	        CurrentColumn = itemColumns;
	    }
	}

	protected virtual void StartContainer(HtmlHelper html)
	{
	    CurrentContainer = new TagBuilder("div");
	    CurrentContainer.AddCssClass("container");

	    html.ViewContext.Writer.Write(CurrentContainer.ToString(TagRenderMode.StartTag));
	    IsContainerOpen = true;
	}

	protected virtual void EndContainer(HtmlHelper html)
	{
	    html.ViewContext.Writer.Write(CurrentContainer.ToString(TagRenderMode.EndTag));
	    IsContainerOpen = false;
	}

	protected virtual void StartRow(HtmlHelper html)
	{
	    CurrentRow = new TagBuilder("div");
	    CurrentRow.AddCssClass("row");

	    html.ViewContext.Writer.Write(CurrentRow.ToString(TagRenderMode.StartTag));
	    IsRowOpen = true;
	}

	protected virtual void EndRow(HtmlHelper html)
	{
	    html.ViewContext.Writer.Write(CurrentRow.ToString(TagRenderMode.EndTag));
	    IsRowOpen = false;
	}

	protected virtual bool IsHeroTag(string templateTag)
	{
	    return templateTag == SiteDisplayOptions.Hero;
	}
}

SiteDisplayOptions.cs

public static class SiteDisplayOptions
{
    public const string Hero = "Hero";
    public const string FullWidth = "FullWidth";
    public const string TwoThirdsWidth = "TwoThirdsWidth";
    public const string HalfWidth = "HalfWidth";
    public const string OneThirdWidth = "OneThirdWidth";
}