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