ASP.NET GetFullHtmlFieldId不返回有效身份证件 [英] ASP.NET GetFullHtmlFieldId not returning valid id

问题描述

在MVC2模板，我通常使用 this.ViewData.TemplateInfo.GetFullHtmlFieldId（字段名）
生成一个HTML元素的ID字段。这已在大多数情况下工作。

In MVC2 template, I normally use this.ViewData.TemplateInfo.GetFullHtmlFieldId(fieldName) to generate the id field of an html element. This has worked in most of the cases.

然而，这种方法实际上并不返回<一href=\"http://stackoverflow.com/questions/1482925/rendering-the-field-name-in-an-editortemplate-rendered-through-editorfor\">valid id字段，它只是preFIX 字段名与 ViewData.TemplateInfo.HtmlField preFIX 这使集合时导致的问题，我有 [] 在HtmlField preFIX。

However this method does not actually return valid id field, it merely prefix fieldName with ViewData.TemplateInfo.HtmlFieldPrefix, this is causing problems for me when rendering collections which has [] in the HtmlFieldPrefix.

我已经手动转换这些字符为 _ 在哪里找到需要，但是这似乎不优雅（重复code）中，有没有人发现了一个好办法，妥善产生id字段？

I have been manually converting those characters to _ where I find the need, but this seems to be not elegant (repeated code), has anyone found a good way to generate id field properly?

推荐答案

你能具体谈谈什么样的问题，你有吗？

Can you be more specific about the kind of problems do you have?

例如，有一种优雅的方法来的编辑可变长度的列表与<一个href=\"http://blog.stevensanderson.com/2010/01/28/validating-a-variable-length-list-aspnet-mvc-2-style/\"相对=nofollow>验证支持提供。虽然它不使用模板仍保持干燥与部分景色。

For example, there is an elegant approach to editing variable length list with validation support provided. While it doesn't use templates still remains DRY with partial views.

虽然IDS不一致 - 名字确定，只有我遇到的问题是，使用jquery.infieldlabel就显得标签的for属性（由GetFullHtmlFieldId LabelFor帮手内部产生的）不匹配相应TextBoxFor输入ID。所以，我创建了一个只是用来ID生成同样的方法LabelForCollectionItem helper方法作为TextBox - TagBuilder.GenerateId（全名）

While the ids are inconsistent - the names are OK and only problem I encountered is that using jquery.infieldlabel it appeared that label's for attribute (generated by GetFullHtmlFieldId inside LabelFor helper) didn't match id of the appropriate TextBoxFor input. So I created LabelForCollectionItem helper method that just uses the same method for id generation as the TextBox - TagBuilder.GenerateId(fullName)

也许code不符合您的需要，但希望这将帮助别人，因为我找到了解决我的问题第一搜索中你的问题。

Maybe the code doesn't correspond to your need but hope it will help somebody since I found your question among the first searching for solution to my problem.

public static class LabelExtensions
{
    /// <summary>
    /// Generates Label with "for" attribute corresponding to the id rendered by input (e.g. TextBoxFor), 
    /// for the case when input is a collection item (full name contains []).
    /// GetFullHtmlFieldId works incorrect inside Html.BeginCollectionItem due to brackets presense.
    /// This method copies TextBox's id generation.
    /// </summary>
    public static MvcHtmlString LabelForCollectionItem<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression,
               string labelText = null, object htmlAttributes = null) where TModel : class
    {
        var tag = new TagBuilder("label");
        tag.MergeAttributes(new RouteValueDictionary(htmlAttributes)); // to convert an object into an IDictionary

        // set inner text
        string htmlFieldName = ExpressionHelper.GetExpressionText(expression);
        string innerText = labelText ?? GetDefaultLabelText(html, expression, htmlFieldName);
        if (string.IsNullOrEmpty(innerText))
        {
            return MvcHtmlString.Empty;
        }
        tag.SetInnerText(innerText);

        // set for attribute
        string forId = GenerateTextBoxId(tag, html, htmlFieldName);
        tag.Attributes.Add("for", forId);

        return MvcHtmlString.Create(tag.ToString(TagRenderMode.Normal));
    }

    /// <summary>
    /// Extracted from System.Web.Mvc.Html.InputExtensions
    /// </summary>
    private static string GenerateTextBoxId<TModel>(TagBuilder tagBuilder, HtmlHelper<TModel> html, string htmlFieldName)
    {
        string fullName = html.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(htmlFieldName);
        tagBuilder.GenerateId(fullName);
        string forId = tagBuilder.Attributes["id"];
        tagBuilder.Attributes.Remove("id");
        return forId;
    }

    /// <summary>
    /// Extracted from System.Web.Mvc.Html.LabelExtensions
    /// </summary>
    private static string GetDefaultLabelText<TModel, TValue>(HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TValue>> expression, string htmlFieldName)
    {
        var metadata = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);
        string labelText = metadata.DisplayName ?? metadata.PropertyName ?? htmlFieldName.Split('.').Last();
        return labelText;
    }
}

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