Experience Sitecore !

I very love Glass Mapper as (once being configured) it takes away from you much of the manual efforts of wiring up your models.

Often working with Rendering Parameters, I decided to simplify their usage by having a strongly-typed HTML Helper powered by Glass Mapper. Here is how the usage looks like:

<div class="@(Html.GetRenderingParametersClassFor<ISingleClass>(m => m.Class))">
   your content here
</div>

It benefits from usage simplicity and also from having IntelliSense. Here's an example of what ISingleClass looks like:

[SitecoreType(TemplateId = ISingleClassConstants.TemplateIdString)]
public partial interface ISingleClass : IGlassBase
{   
    [SitecoreField(ISingleClassConstants.ClassFieldName)]
    Guid Class { get; }
}

In Sitecore items of a given type may look as smth. similar below:

OK, won't make it any longer: here's the code that does all the magic:

public static class HtmlHelperExtensions
{
    public static string GetRenderingParametersClassFor<T>(this HtmlHelper html, Func<T, object> getField, string fieldName = "Class") where T : class
    {
        var selectedItem = GetSelectedRenderingParameter(html, getField);
        return selectedItem?[fieldName] ?? "";
    }


    private static Item GetSelectedRenderingParameter<T>(this HtmlHelper html, Func<T, object> getField) where T : class
    {
        T renderingParameters = GetRenderingParameters<T>(html);

        var selectedItemId = getField(renderingParameters)?.ToString();
        return Context.Database.GetItem(selectedItemId);
    }

    public static T GetRenderingParameters<T>(this HtmlHelper html) where T : class
    {
        //TODO: wire-up ISitecoreService to get resolved via DI of your choise
        var sitecoreService = new SitecoreService(PageContext.Current.Database);

        var parameters = RenderingContext.CurrentOrNull.Rendering["Parameters"];
        var nameValueCollection = WebUtil.ParseUrlParameters(parameters);
        var config = sitecoreService.GlassContext[typeof(T)] as SitecoreTypeConfiguration;

        var renderingParametersModelFactory = new RenderingParametersModelFactory(sitecoreService);
        return renderingParametersModelFactory.CreateModel<T>(nameValueCollection, config.TemplateId);
    }
}

Bonus: in some cases you may also want selecting a HTML tag from rendering parameters, for example your editors could choose between heading tags they want to be on your rendering (like H1, H2, H3, H4 or may be just a generating paragraph P-tag):

In that case you can add one more method into the above HTML helper class:

public static MvcTag TagFrom<T>(this HtmlHelper html, Func<T, object> getField, string className = null) where T : class
{
    var selectedItem = GetSelectedRenderingParameter(html, getField);
    string tag = selectedItem?["Tag"] ?? "";

    html.ViewContext.ViewBag.Tag = tag;

    if (!string.IsNullOrWhiteSpace(tag)) 
    {
        var tagBuilder = new TagBuilder(tag);
    
        if (!string.IsNullOrWhiteSpace(className))
        {
            tagBuilder.Attributes.Add("class", className);
        }
        
        html.ViewContext.Writer.Write(tagBuilder.ToString(TagRenderMode.StartTag));
    }

    return new MvcTag(html.ViewContext);
}

Once compiled, you can then render you tags as below:

@using (Html.TagFrom<ITagRenderingParameter>(m => m.Tag, "tag_class"))
{
    @Html.Glass().Editable(m => m.Title)
}

And choose which HTML tag just from a Rendering Parameters dropdown:

Hope this helps!