Thursday, September 7, 2017

HTML Helpers - ASP.NET MVC's equivalent of JSTL Custom Taglibs

I have found the equivalent of Java's JSTL Custom Taglibs: HTML Helpers.

I started moving logic out of my Razor Views and into HTML Helper classes.

Here's my first, and it's a beauty (uses recursion to build out nested lists):

    public static class CategoryExtensions
        public static IHtmlString CategoryDisplay(this HtmlHelper helper, IEnumerable categories, int indentSize)
            string indentString = "";
            for (int i = 0; i < indentSize; i++)
                indentString += " ";
            StringBuilder stringBuilder = new StringBuilder();
\n"); stringBuilder.Append(BuildList(categories, indentString)); stringBuilder.Append(indentString).Append("
"); return new HtmlString(stringBuilder.ToString()); } private static IHtmlString BuildList(IEnumerable categories, string indentString) { StringBuilder stringBuilder = new StringBuilder(); stringBuilder.Append(indentString).Append("
    \n"); foreach (Category category in categories) { stringBuilder.Append(indentString).Append("
  1. \n"); stringBuilder.Append(indentString).Append("
    \n"); stringBuilder.Append(indentString).Append(" " + category.CategoryName + "\n"); stringBuilder.Append(indentString).Append("
    \n"); if (category.SubCategories.Any()) { indentString += " "; stringBuilder.Append(BuildList(category.SubCategories, indentString)); } stringBuilder.Append(indentString).Append("
  2. \n"); } stringBuilder.Append(indentString).Append("
\n"); return new HtmlString(stringBuilder.ToString()); } }
I'm glad to get the logic out of the Razor views (which should not have such complex logic) and into proper C# classes.

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