public static string RenderControlGroupSelectElement(HtmlHelper html, BootstrapSelectElementModel inputModel, BootstrapLabelModel labelModel, BootstrapInputType inputType)
        {
            if (string.IsNullOrEmpty(inputModel.htmlFieldName) || inputModel.selectList == null) return null;

            string input = string.Empty;

            if(inputType == BootstrapInputType.DropDownList)
                input = Renderer.RenderSelectElement(html, inputModel, BootstrapInputType.DropDownList);

            if (inputType == BootstrapInputType.ListBox)
                input = Renderer.RenderSelectElement(html, inputModel, BootstrapInputType.ListBox);

            string label = Renderer.RenderLabel(html, labelModel ?? new BootstrapLabelModel
            {
                htmlFieldName = inputModel.htmlFieldName,
                metadata = inputModel.metadata,
                htmlAttributes = new { @class = "control-label" }.ToDictionary()
            });

            bool fieldIsValid = true;
            if(inputModel != null) fieldIsValid = html.ViewData.ModelState.IsValidField(inputModel.htmlFieldName);
            return new BootstrapControlGroup(input, label, ControlGroupType.textboxLike, fieldIsValid).ToHtmlString();
        }
        public static string RenderSelectElement(HtmlHelper html, BootstrapSelectElementModel model, BootstrapInputType inputType)
        {
            string combinedHtml = "{0}{1}{2}";
            if (model.selectedValue != null)
            {
                foreach (var item in model.selectList)
                {
                    if (item.Value == model.selectedValue.ToString())
                        item.Selected = true;
                }
            }

            model.htmlAttributes.MergeHtmlAttributes(html.GetUnobtrusiveValidationAttributes(model.htmlFieldName, model.metadata));
            if (model.tooltipConfiguration != null) model.htmlAttributes.MergeHtmlAttributes(model.tooltipConfiguration.ToDictionary());
            if (model.tooltip != null) model.htmlAttributes.MergeHtmlAttributes(model.tooltip.ToDictionary());
            if (!string.IsNullOrEmpty(model.id)) model.htmlAttributes.AddOrReplace("id", model.id);

            // assign size class
            model.htmlAttributes.AddOrMergeCssClass("class", BootstrapHelper.GetClassForInputSize(model.size));

            // build html for input
            string input = string.Empty;

            if(inputType == BootstrapInputType.DropDownList)
                input = html.DropDownList(model.htmlFieldName, model.selectList, model.optionLabel, model.htmlAttributes.FormatHtmlAttributes()).ToHtmlString();

            if(inputType == BootstrapInputType.ListBox)
                input = html.ListBox(model.htmlFieldName, model.selectList, model.htmlAttributes.FormatHtmlAttributes()).ToHtmlString();

            // account for appendString, prependString, and AppendButtons
            TagBuilder appendPrependContainer = new TagBuilder("div");
            if (!string.IsNullOrEmpty(model.prependString) | !string.IsNullOrEmpty(model.appendString) | model.appendButtons.Count() > 0)
            {
                string addOnPrependString = "";
                string addOnAppendString = "";
                string addOnPrependButtons = "";
                string addOnAppendButtons = "";

                TagBuilder addOn = new TagBuilder("span");
                addOn.AddCssClass("add-on");
                if (!string.IsNullOrEmpty(model.prependString))
                {
                    appendPrependContainer.AddOrMergeCssClass("input-prepend");
                    addOn.InnerHtml = model.prependString;
                    addOnPrependString = addOn.ToString();
                }
                if (!string.IsNullOrEmpty(model.appendString))
                {
                    appendPrependContainer.AddOrMergeCssClass("input-append");
                    addOn.InnerHtml = model.appendString;
                    addOnAppendString = addOn.ToString();
                }
                if (model.appendButtons.Count() > 0)
                {
                    appendPrependContainer.AddOrMergeCssClass("input-append");
                    ((List<BootstrapButton>)model.appendButtons).ForEach(x => addOnAppendButtons += x.ToHtmlString());
                }
                if (model.prependButtons.Count() > 0)
                {
                    appendPrependContainer.AddOrMergeCssClass("input-append");
                    ((List<BootstrapButton>)model.prependButtons).ForEach(x => addOnPrependButtons += x.ToHtmlString());
                }

                appendPrependContainer.InnerHtml = addOnPrependButtons + addOnPrependString + "{0}" + addOnAppendString + addOnAppendButtons;
                combinedHtml = appendPrependContainer.ToString(TagRenderMode.Normal) + "{1}{2}";
            }

            string helpText = model.helpText != null ? model.helpText.ToHtmlString() : string.Empty;
            string validationMessage = "";
            if(model.displayValidationMessage && html.ValidationMessage(model.htmlFieldName) != null )
            {
                string validation = html.ValidationMessage((string)model.htmlFieldName).ToHtmlString();
                validationMessage = new BootstrapHelpText(validation, model.validationMessageStyle).ToHtmlString();
            }

            return MvcHtmlString.Create(string.Format(combinedHtml, input, helpText, validationMessage)).ToString();
        }