Expandí sobre la respuesta de balealexandre y agregué la capacidad de especificar HTML para incluir tanto antes como después del texto de la etiqueta. Agregué un montón de sobrecargas de métodos y comentarios. Espero que esto ayude a la gente!
También se enganchó información desde aquí: Html inside label using Html helper
namespace System.Web.Mvc.Html
{
public static class LabelExtensions
{
/// <summary>Creates a Label with custom Html before the label text. Only starting Html is provided.</summary>
/// <param name="startHtml">Html to preempt the label text.</param>
/// <returns>MVC Html for the Label</returns>
public static MvcHtmlString LabelFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, Func<object, HelperResult> startHtml)
{
return LabelFor(html, expression, startHtml, null, new RouteValueDictionary("new {}"));
}
/// <summary>Creates a Label with custom Html before the label text. Starting Html and a single Html attribute is provided.</summary>
/// <param name="startHtml">Html to preempt the label text.</param>
/// <param name="htmlAttributes">A single Html attribute to include.</param>
/// <returns>MVC Html for the Label</returns>
public static MvcHtmlString LabelFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, Func<object, HelperResult> startHtml, object htmlAttributes)
{
return LabelFor(html, expression, startHtml, null, new RouteValueDictionary(htmlAttributes));
}
/// <summary>Creates a Label with custom Html before the label text. Starting Html and a collection of Html attributes are provided.</summary>
/// <param name="startHtml">Html to preempt the label text.</param>
/// <param name="htmlAttributes">A collection of Html attributes to include.</param>
/// <returns>MVC Html for the Label</returns>
public static MvcHtmlString LabelFor<TModel, TProperty>(this HtmlHelper<TModel> html, Expression<Func<TModel, TProperty>> expression, Func<object, HelperResult> startHtml, IDictionary<string, object> htmlAttributes)
{
return LabelFor(html, expression, startHtml, null, htmlAttributes);
}
/// <summary>Creates a Label with custom Html before and after the label text. Starting Html and ending Html are provided.</summary>
/// <param name="startHtml">Html to preempt the label text.</param>
/// <param name="endHtml">Html to follow the label text.</param>
/// <returns>MVC Html for the Label</returns>
public static MvcHtmlString LabelFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, Func<object, HelperResult> startHtml, Func<object, HelperResult> endHtml)
{
return LabelFor(html, expression, startHtml, endHtml, new RouteValueDictionary("new {}"));
}
/// <summary>Creates a Label with custom Html before and after the label text. Starting Html, ending Html, and a single Html attribute are provided.</summary>
/// <param name="startHtml">Html to preempt the label text.</param>
/// <param name="endHtml">Html to follow the label text.</param>
/// <param name="htmlAttributes">A single Html attribute to include.</param>
/// <returns>MVC Html for the Label</returns>
public static MvcHtmlString LabelFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, Func<object, HelperResult> startHtml, Func<object, HelperResult> endHtml, object htmlAttributes)
{
return LabelFor(html, expression, startHtml, endHtml, new RouteValueDictionary(htmlAttributes));
}
/// <summary>Creates a Label with custom Html before and after the label text. Starting Html, ending Html, and a collection of Html attributes are provided.</summary>
/// <param name="startHtml">Html to preempt the label text.</param>
/// <param name="endHtml">Html to follow the label text.</param>
/// <param name="htmlAttributes">A collection of Html attributes to include.</param>
/// <returns>MVC Html for the Label</returns>
public static MvcHtmlString LabelFor<TModel, TProperty>(this HtmlHelper<TModel> html, Expression<Func<TModel, TProperty>> expression, Func<object, HelperResult> startHtml, Func<object, HelperResult> endHtml, IDictionary<string, object> htmlAttributes)
{
ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, html.ViewData);
string htmlFieldName = ExpressionHelper.GetExpressionText(expression);
//Use the DisplayName or PropertyName for the metadata if available. Otherwise default to the htmlFieldName provided by the user.
string labelText = metadata.DisplayName ?? metadata.PropertyName ?? htmlFieldName.Split('.').Last();
if (String.IsNullOrEmpty(labelText))
{
return MvcHtmlString.Empty;
}
//Create the new label.
TagBuilder tag = new TagBuilder("label");
//Add the specified Html attributes
tag.MergeAttributes(htmlAttributes);
//Specify what property the label is tied to.
tag.Attributes.Add("for", html.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldId(htmlFieldName));
//Run through the various iterations of null starting or ending Html text.
if (startHtml == null && endHtml == null) tag.InnerHtml = labelText;
else if (startHtml != null && endHtml == null) tag.InnerHtml = string.Format("{0}{1}", startHtml(null).ToHtmlString(), labelText);
else if (startHtml == null && endHtml != null) tag.InnerHtml = string.Format("{0}{1}", labelText, endHtml(null).ToHtmlString());
else tag.InnerHtml = string.Format("{0}{1}{2}", startHtml(null).ToHtmlString(), labelText, endHtml(null).ToHtmlString());
return MvcHtmlString.Create(tag.ToString());
}
}
}
Esto provocará una excepción llamada ambigua ya que la firma es idéntico al método de extensión existente. No hay métodos de extensión superiores. – Nilzor
@Nilzor, no hay extensión con esos parámetros, puede usar el código en mi respuesta, recuerde, es 'LabelFor' no' EditorFor'. – balexandre
Sí, tienes razón. Lo que debería haber dicho es que sus métodos no anulan el constructo @ Html.LabelFor (model => model.Register.UserName). Si intenta agregar una sobrecarga con esta firma, obtendrá una excepción de llamada ambigua, como lo he probado. Su solución es sólida, pero requiere que cambie el código de invocación (las vistas). – Nilzor