Question

我正在使用ASP.NET MVC 2，但我不认为我已经听说过在MVC 3或4中修复了这个问题，但无论如何：

这是我的测试视图代码：

<br />
<%= Html.LabelFor( m => m.FieldFoo ) %>
<%= Html.TextBoxFor( m => m.FieldFoo ) %>

<br />
<%= Html.LabelFor( m => m.CustomFieldValues[0].Value ) %>
<%= Html.TextBoxFor( m => m.CustomFieldValues[0].Value ) %>

这就是呈现的内容：

<br />
<label for="FieldFoo">Foo?</label>
<input id="FieldFoo" name="FieldFoo" type="text" value="foo" />

<br />
<label for="CustomFieldValues[0]_Value">Value</label>
<input id="CustomFieldValues_0__Value" name="CustomFieldValues[0].Value" type="text" value="bar" />

发现差异：索引属性CustomFieldValues未将[和]字符替换为_属性的for=""。为什么呢？

我进入LabelFor代码并看到它调用html.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldId(htmlFieldName));而MVC的内部InputHelper有自己的逻辑使用TagBuilder.CreateSanitizedId()这解释了为什么它变得不同{{1}属性值。

MVC 2中是否有解决方法？

Answer 1

ASP.NET MVC 2没有带有htmlAttributes参数的LabelFor扩展方法。见blog post。我们可以创建一个扩展，它将添加此参数以及解决您的上述问题。这是样本，

public static class MyTagBuilder
{
    public static string CreateSanitizedId(string originalId)
    {
        return CreateSanitizedId(originalId, HtmlHelper.IdAttributeDotReplacement);
    }

    public static string CreateSanitizedId(string originalId, string invalidCharReplacement)
    {
        if (String.IsNullOrEmpty(originalId))
        {
            return null;
        }

        if (invalidCharReplacement == null)
        {
            throw new ArgumentNullException("invalidCharReplacement");
        }

        char firstChar = originalId[0];
        if (!Html401IdUtil.IsLetter(firstChar))
        {
            // the first character must be a letter
            return null;
        }

        StringBuilder sb = new StringBuilder(originalId.Length);
        sb.Append(firstChar);

        for (int i = 1; i < originalId.Length; i++)
        {
            char thisChar = originalId[i];
            if (Html401IdUtil.IsValidIdCharacter(thisChar))
            {
                sb.Append(thisChar);
            }
            else
            {
                sb.Append(invalidCharReplacement);
            }
        }

        return sb.ToString();
    }

    private static class Html401IdUtil
    {
        private static bool IsAllowableSpecialCharacter(char c)
        {
            switch (c)
            {
                case '-':
                case '_':
                case ':':
                    // note that we're specifically excluding the '.' character
                    return true;

                default:
                    return false;
            }
        }

        private static bool IsDigit(char c)
        {
            return ('0' <= c && c <= '9');
        }

        public static bool IsLetter(char c)
        {
            return (('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z'));
        }

        public static bool IsValidIdCharacter(char c)
        {
            return (IsLetter(c) || IsDigit(c) || IsAllowableSpecialCharacter(c));
        }
    }

}
public static class LabelExtensions
{
    public static MvcHtmlString LabelFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, object htmlAttributes)
    {
        return LabelFor(html, expression, new RouteValueDictionary(htmlAttributes));
    }
    public static MvcHtmlString LabelFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, IDictionary<string, object> htmlAttributes)
    {
        ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, html.ViewData);
        string htmlFieldName = ExpressionHelper.GetExpressionText(expression);
        string labelText = metadata.DisplayName ?? metadata.PropertyName ?? htmlFieldName.Split('.').Last();
        if (String.IsNullOrEmpty(labelText))
        {
            return MvcHtmlString.Empty;
        }

        TagBuilder tag = new TagBuilder("label");
        tag.MergeAttributes(htmlAttributes);
        tag.Attributes.Add("for", MyTagBuilder.CreateSanitizedId(html.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(htmlFieldName)));
        tag.SetInnerText(labelText);
        return MvcHtmlString.Create(tag.ToString(TagRenderMode.Normal));
    }
}


<%@ Import Namespace="NameSpaceOfTheExtensionMethodClass" %>


<%= Html.LabelFor(m => m.CustomFieldValues[0].Value, new { })%>
<%= Html.TextBoxFor( m => m.CustomFieldValues[0].Value )%>

GetFullHtmlFieldId返回不正确的id属性值

1 个答案: