Question

我的ASP.NET MVC Razor页面上需要一个表单。我的偏好是使用以下语法：

@using (Html.BeginForm())
{
}

但是，我需要在表单中添加几个属性。所以我最终得到了以下内容：

@using (Html.BeginForm(null, null, FormMethod.Post, new { name = "value" }))
{
}

然而，这具有不希望的副作用。如果此页面的请求中存在查询参数，则第一个表单会在提交表单时传递它们。但是，第二个版本没有。

我真的不知道为什么BeginForm()不支持属性，但有一种直接的方法可以向BeginForm()添加属性，并且在提交for时仍会传递任何查询参数？

修改

在研究之后，似乎最好的解决方案是这样的：

<form action="@Request.RawUrl" method="post" name="value">
</form>

但是，使用此语法时，将禁用客户端验证。在没有更复杂和可能不可靠的结构的情况下，似乎没有很好的解决方案。

Answer 1

确实如此，但我会使用自定义帮助程序来保留用于客户端验证的表单上下文：

public static class FormExtensions
{
    private static object _lastFormNumKey = new object();

    public static IDisposable BeginForm(this HtmlHelper htmlHelper, object htmlAttributes)
    {
        string rawUrl = htmlHelper.ViewContext.HttpContext.Request.RawUrl;
        return htmlHelper.FormHelper(rawUrl, FormMethod.Post, HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes));
    }

    private static int IncrementFormCount(IDictionary items)
    {
        object obj2 = items[_lastFormNumKey];
        int num = (obj2 != null) ? (((int)obj2) + 1) : 0;
        items[_lastFormNumKey] = num;
        return num;
    }

    private static string DefaultFormIdGenerator(this HtmlHelper htmlhelper)
    {
        int num = IncrementFormCount(htmlhelper.ViewContext.HttpContext.Items);
        return string.Format(CultureInfo.InvariantCulture, "form{0}", new object[] { num });
    }

    private static IDisposable FormHelper(this HtmlHelper htmlHelper, string formAction, FormMethod method, IDictionary<string, object> htmlAttributes)
    {
        var builder = new TagBuilder("form");
        builder.MergeAttributes<string, object>(htmlAttributes);
        builder.MergeAttribute("action", formAction);
        builder.MergeAttribute("method", HtmlHelper.GetFormMethodString(method), true);
        bool flag = htmlHelper.ViewContext.ClientValidationEnabled && !htmlHelper.ViewContext.UnobtrusiveJavaScriptEnabled;
        if (flag)
        {
            builder.GenerateId(htmlHelper.DefaultFormIdGenerator());
        }
        htmlHelper.ViewContext.Writer.Write(builder.ToString(TagRenderMode.StartTag));
        var form = new MvcForm(htmlHelper.ViewContext);
        if (flag)
        {
            htmlHelper.ViewContext.FormContext.FormId = builder.Attributes["id"];
        }
        return form;
    }
}

可以像这样使用：

@using (Html.BeginForm(htmlAttributes: new { name = "value" }))
{
    ...
}

Answer 2

我有类似的问题，这里是快速解决方案（适用于MVC4）。

声明扩展方法：

public static MvcForm BeginForm(this HtmlHelper helper, object htmlAttributes)
{
        return helper.BeginForm(helper.ViewContext.RouteData.Values["Action"].ToString(),
                                helper.ViewContext.RouteData.Values["Controller"].ToString(), 
                                FormMethod.Post, htmlAttributes);
}

并在您的网页中使用它：

@using (Html.BeginForm(htmlAttributes: new {@class="form-horizontal"})) 
{
...
}

Answer 3

对源代码的小修改：

http://aspnetwebstack.codeplex.com/SourceControl/latest#src/System.Web.Mvc/Html/FormExtensions.cs

public static MvcForm BeginForm(this HtmlHelper htmlHelper, object htmlAttributes)
{
   // generates <form action="{current url}" method="post">...</form>
   string formAction = htmlHelper.ViewContext.HttpContext.Request.RawUrl;
   return FormHelper(htmlHelper, formAction, FormMethod.Post, new RouteValueDictionary(htmlAttributes));
}

private static MvcForm FormHelper(this HtmlHelper htmlHelper, string formAction, FormMethod method, IDictionary<string, object> htmlAttributes)
{
   TagBuilder tagBuilder = new TagBuilder("form");
   tagBuilder.MergeAttributes(htmlAttributes);
   // action is implicitly generated, so htmlAttributes take precedence.
   tagBuilder.MergeAttribute("action", formAction);
   // method is an explicit parameter, so it takes precedence over the htmlAttributes.
   tagBuilder.MergeAttribute("method", HtmlHelper.GetFormMethodString(method), true);

   bool traditionalJavascriptEnabled = htmlHelper.ViewContext.ClientValidationEnabled
                                       && !htmlHelper.ViewContext.UnobtrusiveJavaScriptEnabled;

   if (traditionalJavascriptEnabled)
   {
       // forms must have an ID for client validation
       tagBuilder.GenerateId(htmlHelper.ViewContext.FormIdGenerator());
   }

   htmlHelper.ViewContext.Writer.Write(tagBuilder.ToString(TagRenderMode.StartTag));
   MvcForm theForm = new MvcForm(htmlHelper.ViewContext);

   if (traditionalJavascriptEnabled)
   {
       htmlHelper.ViewContext.FormContext.FormId = tagBuilder.Attributes["id"];
   }

   return theForm;
}

将HTML属性添加到Html.BeginForm（）的变化

3 个答案: