MVC4中基于下拉选择的依赖验证

Question

我有一个下拉列表，其值Yes, No 。 如果选择yes我将验证接下来的两个文本框。 如何根据下拉选择进行依赖项验证？

public class MeetingAbstract
    {
        public string HasMaterialPublishedElseWhereLabel { get; set; }
        public string HasMaterialPublishedElseWhereOptions { get; set; }
        [Required]
        public string HasMaterialPublishedElseWhereText { get; set; }


        public string DtPublishedTimeId { get; set; }
        public string DtPublishedTimeLabel { get; set; }
        //validate this based on HasMaterialPublishedElseWhereText =Yes value
        public string DtPublishedTimeText { get; set; }


        public string PublishedPlaceId { get; set; }
        public string PublishedPlaceLabel { get; set; }
 //validate this based on HasMaterialPublishedElseWhereText =Yes value

        public string PublishedPlaceText { get; set; }

 }

视图

<div class="row" style="padding-bottom: 10px">
   <div class="col-md-10">
     <div class="col-md-6">@Html.Label(Model.HasMaterialPublishedElseWhereLabel, 
         new {@class = "control-label mandatory"})</div>
        <div class="col-md-4">
          @{
             options = Model.HasMaterialPublishedElseWhereOptions;
             optionsList = options.Split(',').ToList();
             optionSelect = optionsList.Select(option => new SelectListItem() 
                {Text = option, Value = option}).ToList();
            }
           @Html.DropDownListFor(model => model.HasMaterialPublishedElseWhereText,
                optionSelect, i18n_Models_Abstract.SelectOption, new { @class = "input-
                validation-error form-control" })
          @Html.ValidationMessageFor(model => model.HasMaterialPublishedElseWhereText, 
                i18n_Models_Abstract.RequiredField, 
                new { style = "padding-left: 5px" })

         </div>
       </div>
  </div>
  <div class="row" style="padding-bottom: 10px">
   <div class="col-md-10">
     <div class="col-md-6">@Html.Label(Model.DtPublishedTimeLabel, new {@class =
                    "control-label mandatory"})</div>
     <div class="col-md-4">@Html.TextBoxFor(model => model.DtPublishedTimeText, new \
                  {@class = "form-control", @placeholder = Model.DtPublishedTimeLabel, 
                  required = "required", maxlength = 40})
       @Html.ValidationMessageFor(model => model.DtPublishedTimeText, 
        i18n_Models_Abstract.RequiredField, new { style = "padding-left: 5px" })</div>
       </div>
    </div>
    <div class="row" style="padding-bottom: 10px">
      <div class="col-md-10">
        <div class="col-md-6">@Html.Label(Model.PublishedPlaceLabel, new {@class = 
             "control-label mandatory"})</div>
        <div class="col-md-4">@Html.TextBoxFor(model => model.PublishedPlaceText, new 
              {@class = "form-control", @placeholder = Model.PublishedPlaceLabel, 
              required = "required", maxlength = 40})
        @Html.ValidationMessageFor(model => model.PublishedPlaceText, 
        i18n_Models_Abstract.RequiredField, new { style = "padding-left: 5px" })
       </div>
     </div>
   </div>

Answer 1

我会在您的模型上添加一个Validate方法，该方法将通过ModelState.IsValid调用并公开：

public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) {
    if (this.HasMaterialPublishedElseWhereText == "Yes") {
        yield return new ValidationResult("This isn't valid! Let me tell you why...");
    }
}

然后在您的控制器中只需调用：

if (ModelState.IsValid) {
    //You can only get this far if your Validate method
    //doesn't return any ValidationResult objects.
    //Do your magic!
}

显然，这不会在客户端执行，因此如果需要在客户端进行验证，则可能需要将其引入。

最后要注意的是，如果只有两个值（例如“是”和“否”），则单选按钮可能比下拉菜单更有意义。