internal static Dictionary <string, string> GetOptionAttributes <T>(HtmlSelectListModel <T> listModel, T item)
{
var properties = item.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance).Where(p => listModel.OptionAttributes.Values.Contains(p.Name));
var optionAttributes = new Dictionary <string, string>();
foreach (var p in properties)
{
var p1 = p;
foreach (var oa in listModel.OptionAttributes.Where(oa => p1.Name == oa.Value))
{
optionAttributes.Add(oa.Key, p.GetValue(item, null).ToString());
}
}
return(optionAttributes);
}
internal static void BuildOptionTags <T>(HtmlSelectListModel <T> listModel, StringBuilder optionsBuilder, T item, string selectedValue)
{
var optionAttributes = GetOptionAttributes(listModel, item);
string innerText = GetOptionInnerText(optionAttributes);
if (optionsBuilder == null)
{
optionsBuilder = new StringBuilder();
}
optionsBuilder.Append("<option ");
//bool defaultValueFound = false;
foreach (var attribute in optionAttributes)
{
optionsBuilder.Append(string.Format("{0}=\"{1}\" ", attribute.Key, attribute.Value));
if (attribute.Value == selectedValue)
{
optionsBuilder.Append("selected=\"selected\" ");
//defaultValueFound = true;
}
}
optionsBuilder.Append(">" + innerText + "</option>");
}
/// <summary>
/// Adds increased attributed functionality to DropDownListFor.
/// </summary>
/// <typeparam name="TModel"></typeparam>
/// <typeparam name="TProperty"></typeparam>
/// <typeparam name="T">The type of object in a list.</typeparam>
/// <param name="htmlHelper">The object this method attaches to.</param>
/// <param name="expression">The object the selected value binds to.</param>
/// <param name="listModel">The Model object for creating this list.</param>
/// <returns>MvcHtmlString - Html for Razor pages.</returns>
public static MvcHtmlString DropDownListWithAttributesFor <TModel, TProperty, T>(this HtmlHelper <TModel> htmlHelper, Expression <Func <TModel, TProperty> > expression, HtmlSelectListModel <T> listModel)
{
var dropdown = new TagBuilder("select");
foreach (var selectAttribute in listModel.SelectAttributes)
{
dropdown.Attributes.Add(selectAttribute.Key, selectAttribute.Value);
}
string currentValue = null;
var metadata = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);
if (metadata != null && metadata.Model != null)
{
currentValue = metadata.Model.ToString();
}
var optionsBuilder = new StringBuilder();
foreach (T item in listModel.DataObjects)
{
BuildOptionTags(listModel, optionsBuilder, item, currentValue);
}
if (string.IsNullOrWhiteSpace(currentValue) && listModel.ShouldUseEmptyValue)
{
optionsBuilder.Insert(0, "<option value=\"\">" + listModel.EmptyValueText + "</option>");
}
dropdown.InnerHtml = optionsBuilder.ToString();
return(new MvcHtmlString(dropdown.ToString(TagRenderMode.Normal)));
}