也许你想自己做点什么?
public delegate object Property<T>(T property);
public static HtmlString MultiSelectListFor<TModel, TKey, TProperty>(
this HtmlHelper<TModel> htmlHelper,
Expression<Func<TModel, IEnumerable<TKey>>> forExpression,
IEnumerable<TProperty> enumeratedItems,
Func<TProperty, TKey> idExpression,
Property<TProperty> displayExpression,
Property<TProperty> titleExpression,
object htmlAttributes) where TModel : class
{
//initialize values
var metaData = ModelMetadata.FromLambdaExpression(forExpression, htmlHelper.ViewData);
var propertyName = metaData.PropertyName;
var propertyValue = htmlHelper.ViewData.Eval(propertyName).ToStringOrEmpty();
var enumeratedType = typeof(TProperty);
//check for problems
if (enumeratedItems == null) throw new ArgumentNullException("The list of items cannot be null");
//build the select tag
var returnText = string.Format("<select multiple=\"multiple\" id=\"{0}\" name=\"{0}\"", HttpUtility.HtmlEncode(propertyName));
if (htmlAttributes != null)
{
foreach (var kvp in htmlAttributes.GetType().GetProperties()
.ToDictionary(p => p.Name, p => p.GetValue(htmlAttributes, null)))
{
returnText += string.Format(" {0}=\"{1}\"", HttpUtility.HtmlEncode(kvp.Key),
HttpUtility.HtmlEncode(kvp.Value.ToStringOrEmpty()));
}
}
returnText += ">\n";
//build the options tags
foreach (TProperty listItem in enumeratedItems)
{
var idValue = idExpression(listItem).ToStringOrEmpty();
var displayValue = displayExpression(listItem).ToStringOrEmpty();
var titleValue = titleExpression(listItem).ToStringOrEmpty();
returnText += string.Format("<option value=\"{0}\" title=\"{1}\"",
HttpUtility.HtmlEncode(idValue), HttpUtility.HtmlEncode(titleValue));
if (propertyValue.Contains(idValue))
{
returnText += " selected=\"selected\"";
}
returnText += string.Format(">{0}</option>\n", HttpUtility.HtmlEncode(displayValue));
}
//close the select tag
returnText += "</select>";
return new HtmlString(returnText);
}