private static string BooleanTemplateDropDownList(bool?value) { StringBuilder builder = new StringBuilder(); TagBuilder selectTag = new TagBuilder("select"); selectTag.AddCssClass("list-box"); selectTag.AddCssClass("tri-state"); selectTag.Attributes["disabled"] = "disabled"; builder.Append(selectTag.ToString(TagRenderMode.StartTag)); foreach (SelectListItem item in DefaultEditorTemplates.TriStateValues(value)) { builder.Append(SelectExtensions.ListItemToOption(item)); } builder.Append(selectTag.ToString(TagRenderMode.EndTag)); return(builder.ToString()); }