Question

如何使下面的剃刀选择选项禁用选择选项？

@Html.DropDownListFor(model => model.RiskChange, new List<SelectListItem>
      {                                      
        new SelectListItem{ Text="Low", Value = "Low" },
        new SelectListItem{ Text="Medium", Value = "Medium" },
        new SelectListItem{ Text="High", Value = "High" },
      }, "Select", new { @class = "form-control" , onchange = "onRiskChange()" })

使它像这样工作。

<select class="form-control"  name="RiskChange" >
         <option selected="true" disabled="disabled">Select</option>
         <option value="Low" >Low</option>
         <option  value="Medium"  >Medium</option>
         <option  value="High" >High</option>
</select>

Answer 1

不幸的是，默认SelectListItem不具有disabled属性的属性（并且无法从disabled创建optionLabel属性），因此无法设置{{1使用标准disabled在option元素中的}}属性。但是，您可以创建使用DropDownListFor属性的自定义帮助程序：

disabled

用法

public static class CustomHelper
{
    public static MvcHtmlString CustomDropDownListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IEnumerable<SelectListItem> selectList, string optionLabel, object htmlAttributes)
    {   
        if (expression == null)
        {
            throw new ArgumentNullException("expression");
        }

        ModelMetadata metadata = ModelMetadata.FromLambdaExpression<TModel, TProperty>(expression, htmlHelper.ViewData);
        string expressionName = ExpressionHelper.GetExpressionText(expression);
        string fullName = htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(expressionName);

        if (String.IsNullOrEmpty(fullName))
        {
            throw new ArgumentException("name");
        }

        var builder = new TagBuilder("select");

        // add default attributes here
        builder.Attributes.Add("name", fullName);

        // merge htmlAttributes here

        if (htmlAttributes != null)
        {
            var attr = HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes);
            builder.MergeAttributes(attr);
        }

        var sb = new StringBuilder();

        // if option label contains any string value,
        // create option placeholder with disabled and selected attribute
        if (!string.IsNullOrEmpty(optionLabel))
        {
            sb.Append(string.Format("<option selected='true' disabled='disabled'>{0}</option>", optionLabel));
        }

        foreach (var item in selectList)
        {
            sb.Append(string.Format("<option value='{0}'>{1}</option>", item.Value, item.Text));
        }

        builder.InnerHtml = sb.ToString();
        return MvcHtmlString.Create(builder.ToString(TagRenderMode.Normal));
    }
}

注意：可以找到here来创建具有自定义属性的选项列表的类似方法。

参考：SelectExtensions.DropDownListFor() method

如何禁用Razor SelectListItem中的默认选项？

1 个答案: