private static string CreateOption(SelectListItemTree item, int level, string indentation)
{
StringBuilder htmlBuilder = new StringBuilder();
TagBuilder option = new TagBuilder("option");
option.InnerHtml = GetIndentation(level, indentation) + System.Web.HttpUtility.HtmlEncode(item.Text);
if (item.Value != null)
{
option.Attributes["Value"] = item.Value;
}
if (item.Selected)
{
option.Attributes["selected"] = "selected";
}
htmlBuilder.AppendLine(option.ToString());
if (item.Items != null)
{
++level;
foreach (var i in item.Items)
{
htmlBuilder.AppendLine(CreateOption(i, level, indentation));
}
}
return(htmlBuilder.ToString());
}
public static IHtmlString DropDownListTree(this HtmlHelper htmlHelper, string name, IEnumerable <SelectListItemTree> selectListItemTree, IDictionary <string, object> htmlAttributes, bool allowMutiple, string optionLabel, string indentation)
{
ModelState state;
name = htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(name);
if (string.IsNullOrEmpty(name))
{
throw new ArgumentException("NULL", "name");
}
int level = 0;
TagBuilder selectBuilder = new TagBuilder("select");
StringBuilder optionBuilder = new StringBuilder();
//var blankOption = new TagBuilder("option");
//optionBuilder.AppendLine(blankOption.ToString());
if (optionLabel != null)
{
SelectListItemTree item = new SelectListItemTree();
item.Text = optionLabel;
item.Value = string.Empty;
optionBuilder.AppendLine(CreateOption(item, level, indentation));
}
foreach (var item in selectListItemTree)
{
optionBuilder.AppendLine(CreateOption(item, level, indentation));
}
selectBuilder.InnerHtml = optionBuilder.ToString();
selectBuilder.MergeAttributes <string, object>(htmlAttributes);
selectBuilder.MergeAttribute("name", name, true);
selectBuilder.GenerateId(name);
if (allowMutiple)
{
selectBuilder.MergeAttribute("mutiple", "mutiple");
}
if (htmlHelper.ViewData.ModelState.TryGetValue(name, out state) && (state.Errors.Count > 0))
{
selectBuilder.AddCssClass(HtmlHelper.ValidationInputCssClassName);
}
return(new HtmlString(selectBuilder.ToString()));
}