javascript - Knockout ValidationMessage 绑定(bind)不显示消息

Question

我正在尝试在表单的多个部分上使用knockout.validation。其中大部分都工作正常，并且可以使用内置的消息附加程序，但我有 1 个特定字段，我需要自己手动将消息添加到 DOM。

不过，我在让它工作时遇到了一个真正的问题，因为如果字段没有发生变化，我根本无法显示文本。我模拟了一个非常小的示例来尽可能接近更大的形式进行说明。

我看到的行为:

• 点击submit 可以正确运行验证(在输入周围添加红色边框)，但不会像应有的那样显示错误消息。
• 在密码框中输入一些内容，然后将其清空，然后单击“提交”，可以正确显示错误消息和红色边框。

由于我正在尝试引入必填字段 - 我无法保证该字段已被修改，因此我需要确保第一个案例有效。谁能看出我做错了什么吗？

ko.validation.init({
  registerExtenders: true,
  messagesOnModified: true,
  insertMessages: true,
  decorateInputElement: true,
  decorateElementOnModified: false,
  errorElementClass: "is-invalid",
  messageTemplate: "inline_error"
}, true);

const viewModel = {};
viewModel.submitted = ko.observable(false);
viewModel.clicked = () => { viewModel.submitted(true); };
const onlyIf = ko.computed(() => viewModel.submitted());

viewModel.user = {
  password: ko.observable().extend({
    required: {
      message: `password is required.`,
      onlyIf,
    }
  })
};

ko.applyBindings(viewModel);

.is-invalid {
  border: thick solid red;
}

.text-danger {
   color: red;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.4.2/knockout-min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout-validation/2.0.3/knockout.validation.min.js"></script>

<div id="domTest">
  <button type="button" data-bind="click: clicked">Submit</button>

  <input type="password" class="form-control" id="password" placeholder="Password" data-bind="validationOptions:{ insertMessages: false }, textInput: user.password">
  <div class="text-danger error-message" data-bind="validationMessage: user.password" />
</div>

Answer 1

在此 Github 问题中，validationMessage does not run on initial binding ，stevegreatrex 说您需要将 messagesOnModified 更改为 false:

messagesOnModified: false

从这个问题的答案来看Knockout Validation onlyif object no function and pattern validation (作者:steve-greatrex)您需要更改计算的 onlyIf:

viewModel.onlyIf = ko.computed(() => viewModel.submitted());

然后将 viewModel.user 中的属性 onlyIf 更改为指向计算出的 viewModel.onlyIf:

viewModel.user = {
  password: ko.observable().extend({
    required: {
      message: `password is required.`,
      onlyIf: viewModel.onlyIf(),
    }
  })
};

希望这有帮助。

ko.validation.init({
  registerExtenders: true,
  //messagesOnModified: true,
  messagesOnModified: false,	
  insertMessages: true,
  decorateInputElement: true,
  decorateElementOnModified: false,
  errorElementClass: "is-invalid",
  messageTemplate: "inline_error"
}, true);

const viewModel = {};
viewModel.submitted = ko.observable(false);
viewModel.clicked = () => { viewModel.submitted(true); };
viewModel.onlyIf = ko.computed(() => viewModel.submitted());

viewModel.user = {
  password: ko.observable().extend({
    required: {
      message: `password is required.`,
      onlyIf: viewModel.onlyIf(),
    }
  })
};

ko.applyBindings(viewModel);

.is-invalid {
  border: thick solid red;
}

.text-danger {
   color: red;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.4.2/knockout-min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout-validation/2.0.3/knockout.validation.min.js"></script>

<div id="domTest">
  <button type="button" data-bind="click: clicked">Submit</button>

  <input type="password" class="form-control" id="password" placeholder="Password" data-bind="validationOptions:{ insertMessages: false }, textInput: user.password">
  <div class="text-danger error-message" data-bind="validationMessage: user.password" />
</div>