Updates and LeafInput

Web/Utility/Validation.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Web;
+using System.Web.Mvc;
+
+namespace LeafWeb.Web.Utility
+{
+    public static class Validation
+    {
+        /// <summary>
+        /// Checks the ModelState for an error, and returns the given error string if there is one, or null if there is no error
+        /// Used to set class="error" on elements to present the error to the user
+        /// </summary>
+        /// <typeparam name="TModel"></typeparam>
+        /// <typeparam name="TProperty"></typeparam>
+        /// <param name="htmlHelper"></param>
+        /// <param name="expression"></param>
+        /// <param name="error"></param>
+        /// <returns></returns>
+        public static MvcHtmlString ValidationErrorFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, string error)
+        {
+            if (HasError(htmlHelper, ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData),ExpressionHelper.GetExpressionText(expression)))
+                return new MvcHtmlString(error);
+            else
+                return null;
+        }
+
+
+        private static bool HasError(this HtmlHelper htmlHelper, ModelMetadata modelMetadata, string expression)
+        {
+            string modelName = htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(expression);
+            FormContext formContext = htmlHelper.ViewContext.FormContext;
+            if (formContext == null)
+                return false;
+
+            if (!htmlHelper.ViewData.ModelState.ContainsKey(modelName))
+                return false;
+
+            ModelState modelState = htmlHelper.ViewData.ModelState[modelName];
+            if (modelState == null)
+                return false;
+
+            ModelErrorCollection modelErrors = modelState.Errors;
+            if (modelErrors == null)
+                return false;
+
+            return (modelErrors.Count > 0);
+        }
+    }
+}