Pipeline processor to add help text to a field in Sitecore.

AddFieldHelpText.cs

using System;
using System.Linq;
using System.Web;
using Sitecore.Diagnostics;
using Sitecore.Globalization;
using Sitecore.Mvc.Presentation;
using Sitecore.Pipelines.GetChromeData;

namespace DEG.SC.ExperienceEditor
{
    public class AddFieldHelpText : GetChromeDataProcessor
    {
        public override void Process(GetChromeDataArgs args)
        {
            Assert.ArgumentNotNull(args, "args");
            Assert.IsNotNull(args.ChromeData, "Chrome Data");

            if (!"field".Equals(args.ChromeType, StringComparison.OrdinalIgnoreCase))
                return;

            var renderingContext = RenderingContext.CurrentOrNull;
            if(renderingContext == null)
                return;

            var currentRendering = GetCurrentRendering();
            if(currentRendering == null)
                return;

            var parameterKey = args.ChromeData.DisplayName + "_HelpText";

            var parameterValue = GetParameterValue(currentRendering, parameterKey);
            if(string.IsNullOrWhiteSpace(parameterValue))
                return;

            args.ChromeData.DisplayName += " " + Translate.Text(parameterValue);
        }

        private string GetParameterValue(Rendering currentRendering, string parameterKey)
        {
            if (currentRendering.Parameters.Any(x => x.Key.Equals(parameterKey, StringComparison.OrdinalIgnoreCase)))
                return currentRendering.Parameters.Where(x => x.Key.Equals(parameterKey, StringComparison.InvariantCultureIgnoreCase))
                                                  .Select(x => x.Value)
                                                  .First();
            var renderingItemParameters = HttpUtility.ParseQueryString(currentRendering.RenderingItem.Parameters);
            return renderingItemParameters[parameterKey] ?? "";
        }

        private Rendering GetCurrentRendering()
        {
            var contextService = Sitecore.Mvc.Common.ContextService.Get();
            if (contextService == null)
                return null;

            var renderingContext = contextService.GetInstances<RenderingContext>().LastOrDefault();
            return renderingContext == null
                       ? null
                       : renderingContext.Rendering;
        }
    }
}