我刚刚注意到Html.CheckBox(“foo”)生成2个输入而不是一个,有人知道为什么是这样吗?
<input id="foo" name="foo" type="checkbox" value="true" />
<input name="foo" type="hidden" value="false" />
我刚刚注意到Html.CheckBox(“foo”)生成2个输入而不是一个,有人知道为什么是这样吗?
<input id="foo" name="foo" type="checkbox" value="true" />
<input name="foo" type="hidden" value="false" />
当前回答
隐藏的输入导致有样式的复选框出现问题。所以我创建了一个Html助手扩展,将隐藏的输入放在包含复选框的div之外。
using System;
using System.Linq.Expressions;
using System.Text;
using System.Web.Mvc;
using System.Web.Routing;
namespace YourNameSpace
{
public static class HtmlHelperExtensions
{
public static MvcHtmlString CustomCheckBoxFor<TModel, TValue>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TValue>> expression, string labelText)
{
//get the data from the model binding
var fieldName = ExpressionHelper.GetExpressionText(expression);
var fullBindingName = htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(fieldName);
var fieldId = TagBuilder.CreateSanitizedId(fullBindingName);
var metaData = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);
var modelValue = metaData.Model;
//create the checkbox
TagBuilder checkbox = new TagBuilder("input");
checkbox.MergeAttribute("type", "checkbox");
checkbox.MergeAttribute("value", "true"); //the visible checkbox must always have true
checkbox.MergeAttribute("name", fullBindingName);
checkbox.MergeAttribute("id", fieldId);
//is the checkbox checked
bool isChecked = false;
if (modelValue != null)
{
bool.TryParse(modelValue.ToString(), out isChecked);
}
if (isChecked)
{
checkbox.MergeAttribute("checked", "checked");
}
//add the validation
checkbox.MergeAttributes(htmlHelper.GetUnobtrusiveValidationAttributes(fieldId, metaData));
//create the outer div
var outerDiv = new TagBuilder("div");
outerDiv.AddCssClass("checkbox-container");
//create the label in the outer div
var label = new TagBuilder("label");
label.MergeAttribute("for", fieldId);
label.AddCssClass("checkbox");
//render the control
StringBuilder sb = new StringBuilder();
sb.AppendLine(outerDiv.ToString(TagRenderMode.StartTag));
sb.AppendLine(checkbox.ToString(TagRenderMode.SelfClosing));
sb.AppendLine(label.ToString(TagRenderMode.StartTag));
sb.AppendLine(labelText); //the label
sb.AppendLine("<svg width=\"10\" height=\"10\" class=\"icon-check\"><use xlink:href=\"/icons.svg#check\"></use></svg>"); //optional icon
sb.AppendLine(label.ToString(TagRenderMode.EndTag));
sb.AppendLine(outerDiv.ToString(TagRenderMode.EndTag));
//create the extra hidden input needed by MVC outside the div
TagBuilder hiddenCheckbox = new TagBuilder("input");
hiddenCheckbox.MergeAttribute("type", HtmlHelper.GetInputTypeString(InputType.Hidden));
hiddenCheckbox.MergeAttribute("name", fullBindingName);
hiddenCheckbox.MergeAttribute("value", "false");
sb.Append(hiddenCheckbox.ToString(TagRenderMode.SelfClosing));
//return the custom checkbox
return MvcHtmlString.Create(sb.ToString());
}
结果
<div class="checkbox-container">
<input checked="checked" id="Model_myCheckBox" name="Model.myCheckBox" type="checkbox" value="true">
<label class="checkbox" for="Model_myCheckBox">
The checkbox label
<svg width="10" height="10" class="icon-check"><use xlink:href="/icons.svg#check"></use></svg>
</label>
</div>
<input name="Model.myCheckBox" type="hidden" value="false">
其他回答
当我使用WebGrid时,我发现这确实引起了问题。WebGrid上的排序链接将由加倍的查询字符串或x=true&x=false转换为x=true,false,并在复选框中导致解析错误。
我最终使用jQuery在客户端删除隐藏字段:
<script type="text/javascript">
$(function () {
// delete extra hidden fields created by checkboxes as the grid links mess this up by doubling the querystring parameters
$("input[type='hidden'][name='x']").remove();
});
</script>
在2020/11和。net 5预览版中,有一个拉请求应该使这种行为可控。谢谢大家!
不管怎样,如果有人觉得它有用,.NET Core 3.0的Alexander Trofimov的回答:
public static IHtmlContent CheckBoxSimple(this IHtmlHelper htmlHelper, string name)
{
TextWriter writer = new StringWriter();
IHtmlContent html = htmlHelper.CheckBox(name);
html.WriteTo(writer, HtmlEncoder.Default);
string checkBoxWithHidden = writer.ToString();
string pureCheckBox = checkBoxWithHidden.Substring(0, checkBoxWithHidden.IndexOf("<input", 1));
return new HtmlString(pureCheckBox);
}
如果未选中复选框,则不提交表单字段。这就是为什么隐藏字段中总是有假值的原因。如果你不选中复选框,表单仍然会有隐藏字段的值。这就是ASP。NET MVC处理复选框值。
如果您想确认这一点,请在表单上放置一个复选框,而不是Html。隐藏,但带有<input type="checkbox" name="MyTestCheckboxValue"></input>。不选中复选框,提交表单并查看服务器端发布的请求值。您将看到没有复选框值。如果你有隐藏字段,它将包含MyTestCheckboxValue项的假值。
这是Alexander Trofimov解决方案的强类型版本:
using System.Web.Mvc;
using System.Web.Mvc.Html;
public static class HelperUI
{
public static MvcHtmlString CheckBoxSimpleFor<TModel>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, bool>> expression, object htmlAttributes)
{
string checkBoxWithHidden = htmlHelper.CheckBoxFor(expression, htmlAttributes).ToHtmlString().Trim();
string pureCheckBox = checkBoxWithHidden.Substring(0, checkBoxWithHidden.IndexOf("<input", 1));
return new MvcHtmlString(pureCheckBox);
}
}
从ASP开始。NET (Core) 5,添加到你的启动:
services.Configure<MvcViewOptions>(options =>
{
// Disable hidden checkboxes
options.HtmlHelperOptions.CheckBoxHiddenInputRenderMode = CheckBoxHiddenInputRenderMode.None;
});
以你的观点为例:
<input class="form-check-input" asp-for="@Model.YourBool" />
此属性的附加隐藏字段不再在表单中创建:
<input class="form-check-input" type="checkbox" data-val="true" data-val-required="The YourBool field is required." id="YourBool" name="YourBool" value="true" />
来源:https://github.com/dotnet/aspnetcore/pull/13014 # issuecomment - 674449674