mvc dropdownlistfor 未标记为必需，但仍然是必需的

发布于 2024-12-03 01:22:45 字数 949 浏览 4 评论 0原文

我在 cshtml 文件中有一个下拉列表：

var kategorie_wlasna = new SelectList(
  (from z in Model.Kategoria
    where !formReadOnly || z.Id == Model.KategoriaWlasnaId 
      select z), 
  "Id", 
  "Nazwa");
...
@Html.DropDownListFor(
  model => model.KategoriaWlasnaId, 
  kategorie_wlasna,
  "----",
  htmlClassDropDownListDef)

在我的 viewModel 中，我的属性没有任何注释为必需：

public long KategoriaWlasnaId { get; set; }

但该字段仍然是必需的。在浏览器中我得到：

<select class="input-validation-error form_object1" data-val="true" data-val-number="The field KategoriaWlasnaId must be a number." data-val-required="The KategoriaWlasnaId field is required." id="KategoriaWlasnaId" name="KategoriaWlasnaId">
  <option value="">-----</option>
  <option value="1227">Wykroczenie</option>
  <option value="1228">Przestępstwo</option>
</select>

我错过了什么？

原文

I have a dropdownlistfor in cshtml file:

var kategorie_wlasna = new SelectList(
  (from z in Model.Kategoria
    where !formReadOnly || z.Id == Model.KategoriaWlasnaId 
      select z), 
  "Id", 
  "Nazwa");
...
@Html.DropDownListFor(
  model => model.KategoriaWlasnaId, 
  kategorie_wlasna,
  "----",
  htmlClassDropDownListDef)

In my viewModel I have the property without any annotations as Required:

public long KategoriaWlasnaId { get; set; }

But the field is still Required. In the browser I get:

<select class="input-validation-error form_object1" data-val="true" data-val-number="The field KategoriaWlasnaId must be a number." data-val-required="The KategoriaWlasnaId field is required." id="KategoriaWlasnaId" name="KategoriaWlasnaId">
  <option value="">-----</option>
  <option value="1227">Wykroczenie</option>
  <option value="1228">Przestępstwo</option>
</select>

What am I missing?

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呆 2024-12-10 01:22:45

这很正常。值类型始终是必需的。您可以将属性设置为可为空：

public long? KategoriaWlasnaId { get; set; }

现在不再需要该属性，并且如果用户未在下拉列表中选择任何元素，则其值将为 null。如果您想让它成为必需的并个性化消息，您可以使用必需属性来装饰它：

[Required]
public long? KategoriaWlasnaId { get; set; }

That's normal. Value types are always required. You could make your property nullable:

public long? KategoriaWlasnaId { get; set; }

Now it will no longer be required and if the user doesn't select any element in the dropdown its value will be null. And if you wanted to make it required and personalize the message you could decorate it with the Required attribute:

[Required]
public long? KategoriaWlasnaId { get; set; }

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小帐篷 2024-12-10 01:22:45

您可以通过将以下行添加到 Application_Start 方法中的 Global.asax.cs 来修改默认的 DataAnnotationsModelValidatorProvider ，以便不需要值类型：

ModelValidatorProviders.Providers.Clear(); 
ModelValidatorProviders.Providers.Add(new DataAnnotationsModelMetadataValidatorProvider());
DataAnnotationsModelValidatorProvider.AddImplicitRequiredAttributeForValueTypes = false;

You can modify the default DataAnnotationsModelValidatorProvider so that value types will not be required by adding the following lines to Global.asax.cs in the Application_Start method:

ModelValidatorProviders.Providers.Clear(); 
ModelValidatorProviders.Providers.Add(new DataAnnotationsModelMetadataValidatorProvider());
DataAnnotationsModelValidatorProvider.AddImplicitRequiredAttributeForValueTypes = false;

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