/// <inheritdoc />
/// <remarks>Does nothing if <see cref="For"/> is <c>null</c>.</remarks>
public override void Process(TagHelperContext context, TagHelperOutput output)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (output == null)
{
throw new ArgumentNullException(nameof(output));
}
IPlatformServices platFormServices = ViewContext.ViewBag.PlatFormServices;
List <SelectListItem> selectItems = null;
if (!string.IsNullOrEmpty(CodeList))
{
selectItems = platFormServices.GetPresentationCodelist(CodeList, TextName, ValueName);
}
// Ensure GenerateSelect() _never_ looks anything up in ViewData.
var items = Enumerable.Empty <SelectListItem>();
if (selectItems != null && selectItems.Count > 0)
{
items = selectItems;
}
if (For == null)
{
var options = Generator.GenerateGroupsAndOptions(optionLabel: null, selectList: items);
output.PostContent.AppendHtml(options);
return;
}
var tagBuilder = Generator.GenerateSelect(
ViewContext,
For.ModelExplorer,
optionLabel: null,
expression: For.Name,
selectList: items,
currentValues: _currentValues,
allowMultiple: _allowMultiple,
htmlAttributes: null);
if (tagBuilder != null)
{
output.MergeAttributes(tagBuilder);
output.PostContent.AppendHtml(tagBuilder.InnerHtml);
}
}