为什么ASP.NET MVC Html.CheckBox输出两个名称相同的投入？ [英] Why does ASP.NET MVC Html.CheckBox output two INPUTs with the same name?

问题描述

为什么在世界上确实行：

 ＆LT;％= Html.CheckBox（ForSale，Model.Product.ForSale）％GT;出售
 

结果下面的HTML：

 ＆LT;输入ID =ForSaleNAME =ForSale类型=复选框VALUE =真/＆GT;
＆LT;输入名称=ForSale类型=隐藏值=FALSE/＆GT;
出售
 

现在，每当我检查框和访问的Request.Form [ForSale] ，我得到的答案可笑真，假 。我应该解析？

这个隐藏字段不会出现其他的HtmlHelper控制，那么，为什么它的CheckBox？

我如何把这个愚蠢的功能了吗？或做了的HtmlHelper 只是长大了它的用处？

更新

从下面的答案，似乎是有这背后一定道理。我有prepared一点点扩展方法，所以我没有去想它（感谢@ EU-GE-NE）：

 公共静态布尔GetCheckBoxValue（这System.Web.Htt prequestBase REQ，
                                        字符串名称）{
        返回Convert.ToBoolean（req.Form.GetValues​​（名称）。首先（））;
    }
 

解决方案

这迫使它是否被选中要包含的字段。如果取消选中复选框它不会被作为页面的一部分 - 他们只派，如果他们检查，然后有一个真值。隐藏字段确保false将如果未选中此复选框，可以发送作为隐藏字段总是被发送。

Why in the world does the line:

<%= Html.CheckBox("ForSale", Model.Product.ForSale)%> For Sale

result in the following HTML:

<input id="ForSale" name="ForSale" type="checkbox" value="true" />
<input name="ForSale" type="hidden" value="false" />
For Sale

Now whenever I check the box and access Request.Form["ForSale"], I get the ridiculous answer of "true,false". Am I supposed to parse that?

This hidden field doesn't appear for the other HtmlHelper controls, so why does it for CheckBox?

How do I turn this stupid "feature" off? Or did the HtmlHelper just outgrow its usefulness?

Update

From the answer below, it seems that there is some logic behind this. I have prepared a little extension method so I don't have to think about it (thanks to @eu-ge-ne):

    public static bool GetCheckBoxValue(this System.Web.HttpRequestBase req, 
                                        string name) {
        return Convert.ToBoolean(req.Form.GetValues(name).First());
    }

解决方案

It forces the field to be included if it's unchecked. If you uncheck a check box it doesn't get sent as part of the page - they are only sent if they're checked, and then there's a value of true. The hidden field ensures that false will be send if the check box is unchecked, as the hidden field is always sent.

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