如何在AddModelError消息中包含一个链接？

Question

我想添加一个ModelState错误,如下所示:

ModelState.AddModelError("", "Some message, <a href="/controller/action">click here</a>)

但是,链接不会被编码,因此显示为文本.我试过用

<%= Html.ValidationSummary(true, "Some message")

代替

<%: Html.ValidationSummary(true, "Some message")

但没有运气.

任何人都知道如何让这个工作？

干杯

Answer 1

最简单的方法(也适用于MVC 4):

在控制器中:

ModelState.AddModelError("", "Please click <a href=\"http://stackoverflow.com\">here</a>");

在视图中:

if (ViewData.ModelState.Any(x => x.Value.Errors.Any()))
{
@Html.Raw(HttpUtility.HtmlDecode(Html.ValidationSummary().ToHtmlString()))
}

Answer 2

ValidationSummary助手自动对所有消息进行HTML编码.一种可能的解决方法是编写自定义验证摘要助手,该助手不对消息进行HTML编码:

public static class HtmlExtensions
{
    public static MvcHtmlString MyValidationSummary(this HtmlHelper htmlHelper, bool excludePropertyErrors, string message)
    {
        var formContext = htmlHelper.ViewContext.ClientValidationEnabled ?  htmlHelper.ViewContext.FormContext : null;
        if (formContext == null && htmlHelper.ViewData.ModelState.IsValid)
        {
            return null;
        }

        string messageSpan;
        if (!string.IsNullOrEmpty(message))
        {
            TagBuilder spanTag = new TagBuilder("span");
            spanTag.SetInnerText(message);
            messageSpan = spanTag.ToString(TagRenderMode.Normal) + Environment.NewLine;
        }
        else
        {
            messageSpan = null;
        }

        var htmlSummary = new StringBuilder();
        TagBuilder unorderedList = new TagBuilder("ul");

        IEnumerable<ModelState> modelStates = null;
        if (excludePropertyErrors)
        {
            ModelState ms;
            htmlHelper.ViewData.ModelState.TryGetValue(htmlHelper.ViewData.TemplateInfo.HtmlFieldPrefix, out ms);
            if (ms != null)
            {
                modelStates = new ModelState[] { ms };
            }
        }
        else
        {
            modelStates = htmlHelper.ViewData.ModelState.Values;
        }

        if (modelStates != null)
        {
            foreach (ModelState modelState in modelStates)
            {
                foreach (ModelError modelError in modelState.Errors)
                {
                    string errorText = GetUserErrorMessageOrDefault(htmlHelper.ViewContext.HttpContext, modelError, null /* modelState */);
                    if (!String.IsNullOrEmpty(errorText))
                    {
                        TagBuilder listItem = new TagBuilder("li");
                        listItem.InnerHtml = errorText;
                        htmlSummary.AppendLine(listItem.ToString(TagRenderMode.Normal));
                    }
                }
            }
        }

        if (htmlSummary.Length == 0)
        {
            htmlSummary.AppendLine(@"<li style=""display:none""></li>");
        }

        unorderedList.InnerHtml = htmlSummary.ToString();

        TagBuilder divBuilder = new TagBuilder("div");
        divBuilder.AddCssClass((htmlHelper.ViewData.ModelState.IsValid) ? HtmlHelper.ValidationSummaryValidCssClassName : HtmlHelper.ValidationSummaryCssClassName);
        divBuilder.InnerHtml = messageSpan + unorderedList.ToString(TagRenderMode.Normal);

        if (formContext != null)
        {
            // client val summaries need an ID
            divBuilder.GenerateId("validationSummary");
            formContext.ValidationSummaryId = divBuilder.Attributes["id"];
            formContext.ReplaceValidationSummary = !excludePropertyErrors;
        }
        return MvcHtmlString.Create(divBuilder.ToString());
    }

    private static string GetUserErrorMessageOrDefault(HttpContextBase httpContext, ModelError error, ModelState modelState)
    {
        if (!String.IsNullOrEmpty(error.ErrorMessage))
        {
            return error.ErrorMessage;
        }
        if (modelState == null)
        {
            return null;
        }

        string attemptedValue = (modelState.Value != null) ? modelState.Value.AttemptedValue : null;
        return String.Format(CultureInfo.CurrentCulture, "The value {0} is invalid.", attemptedValue);
    }
}

然后:

<%= Html.MyValidationSummary(true, "Some message") %>

当然,通过这样做,您应该小心,因为您将这些错误消息放入文本中,因为现在它们不会被HTML编码.这意味着,如果你想用一些特殊字符,如<,>,&进入你的消息,你需要自己的HTML编码,或标记将打破.

Answer 3

<div class="validation-summary-errors">
    <ul>
    <% foreach(var error in ViewData.ModelState.Where(s => s.Value.Errors.Count!=0).SelectMany(s => s.Value.Errors)) { %>
        <li><%= error.ErrorMessage %></li>
    <% } %>
    </ul>
</div>

或剃须刀：

<div class="validation-summary-errors">
    <ul>
    @foreach(var error in ViewData.ModelState.Where(s => s.Value.Errors.Count!=0).SelectMany(s => s.Value.Errors)) {
        <li>@Html.Raw(error.ErrorMessage)</li>
    }
    </ul>
</div>