Form

Form component enhanced based on Element Plus Form.

Form consists of input, radio, select, checkbox and so on. With form, you can collect, verify and submit data.

TIP

The component has been upgraded with a flex layout to replace the old float layout.

Basic Usage

The most basic form includes various input form items, such as input, select, radio, checkbox, etc.

In each Form component, you need to use the bk-form-item component as the container for input items. You can also define the form structure in a configuration-driven manner through the items property. Each form item supports configuring options such as prop, label, and related field attributes.

vue

<template>
  <bk-form :model="form" label-width="auto" style="max-width: 600px">
    <bk-form-item label="Activity name">
      <el-input v-model="form.name" />
    </bk-form-item>
    <bk-form-item label="Activity zone">
      <el-select v-model="form.region" placeholder="please select your zone">
        <el-option label="Zone one" value="shanghai" />
        <el-option label="Zone two" value="beijing" />
      </el-select>
    </bk-form-item>
    <bk-form-item label="Activity time">
      <el-col :span="11">
        <el-date-picker
          v-model="form.date1"
          type="date"
          placeholder="Pick a date"
          style="width: 100%"
        />
      </el-col>
      <el-col :span="2" class="text-center">
        <span class="text-gray-500">-</span>
      </el-col>
      <el-col :span="11">
        <el-time-picker v-model="form.date2" placeholder="Pick a time" style="width: 100%" />
      </el-col>
    </bk-form-item>
    <bk-form-item label="Instant delivery">
      <el-switch v-model="form.delivery" />
    </bk-form-item>
    <bk-form-item label="Activity type">
      <el-checkbox-group v-model="form.type">
        <el-checkbox value="Online activities" name="type"> Online activities </el-checkbox>
        <el-checkbox value="Promotion activities" name="type"> Promotion activities </el-checkbox>
        <el-checkbox value="Offline activities" name="type"> Offline activities </el-checkbox>
        <el-checkbox value="Simple brand exposure" name="type"> Simple brand exposure </el-checkbox>
      </el-checkbox-group>
    </bk-form-item>
    <bk-form-item label="Resources">
      <el-radio-group v-model="form.resource">
        <el-radio value="Sponsor">Sponsor</el-radio>
        <el-radio value="Venue">Venue</el-radio>
      </el-radio-group>
    </bk-form-item>
    <bk-form-item label="Activity form">
      <el-input v-model="form.desc" type="textarea" />
    </bk-form-item>
    <bk-form-item>
      <bk-button type="primary" @click="onSubmit">Create</bk-button>
      <bk-button>Cancel</bk-button>
    </bk-form-item>
  </bk-form>
  <el-divider></el-divider>
  <bk-form :model="form" :items="items" label-width="auto" style="max-width: 600px">
    <bk-form-item>
      <bk-button type="primary" @click="onSubmit">Create</bk-button>
      <bk-button>Cancel</bk-button>
    </bk-form-item>
  </bk-form>
</template>

<script lang="ts" setup>
import { reactive } from "vue"
import type { FormItem } from "vue-business-kit"

const items: FormItem[] = [
  {
    label: "Activity name",
    type: "input",
    prop: "name"
  },
  {
    label: "Activity zone",
    type: "select",
    prop: "region",
    componentProps: {
      placeholder: "please select your zone"
    },
    children: [
      { label: "Zone one", value: "shanghai" },
      { label: "Zone two", value: "beijing" }
    ]
  },
  {
    label: "Activity time",
    type: "date-picker",
    prop: "date1",
    componentProps: {
      type: "datetimerange",
      placeholder: "Pick a date",
      style: { width: "100%" }
    }
  },
  {
    label: "Instant delivery",
    type: "switch",
    prop: "delivery"
  },
  {
    label: "Activity type",
    type: "checkbox-group",
    prop: "type",
    children: [
      { label: "Online activities", value: "Online activities" },
      { label: "Promotion activities", value: "Promotion activities" },
      { label: "Offline activities", value: "Offline activities" },
      { label: "Simple brand exposure", value: "Simple brand exposure" }
    ]
  },
  {
    label: "Resources",
    type: "radio-group",
    prop: "resource",
    children: [
      { label: "Sponsor", value: "Sponsor" },
      { label: "Venue", value: "Venue" }
    ]
  },
  {
    label: "Activity form",
    type: "input",
    prop: "desc",
    componentProps: {
      type: "textarea"
    }
  }
]

// do not use same name with ref
const form = reactive({
  name: "",
  region: "",
  date1: "",
  date2: "",
  delivery: false,
  type: [],
  resource: "",
  desc: ""
})

const onSubmit = () => {
  console.log("submit!")
}
</script>

TIP

W3C regulates that

When there is only one single-line text input field in a form, the user agent should accept Enter in that field as a request to submit the form.

To prevent this behavior, you can add @submit.prevent on <bk-form>.

Multi-Column Form @items

When the vertical space is limited and the form is relatively simple, you can put it in one line.

Set the col-num attribute to specify the number of columns for the form layout.

Alignment

Depending on your design, there are several different ways to align your label element.

You can set the label-position separately in items. If the value is empty, the label-position of bk-form is used.

The label-position attribute decides how labels align, it can be top or left. When set to top, labels will be placed at the top of the form field.

Validation

Form component allows you to verify your data, helping you find and correct errors.

You only need to add the rules attribute to the bk-form component and pass in the validation rules, then set the prop attribute of the form item to the specific key value that needs to be validated. For validation rules, refer to async-validator.

vue

<template>
  <bk-form
    ref="ruleFormRef"
    style="max-width: 600px"
    :model="ruleForm"
    :rules="rules"
    label-width="auto"
  >
    <bk-form-item label="Activity name" prop="name">
      <el-input v-model="ruleForm.name" />
    </bk-form-item>
    <bk-form-item label="Activity zone" prop="region">
      <el-select v-model="ruleForm.region" placeholder="Activity zone">
        <el-option label="Zone one" value="shanghai" />
        <el-option label="Zone two" value="beijing" />
      </el-select>
    </bk-form-item>
    <bk-form-item label="Activity count" prop="count">
      <el-select-v2 v-model="ruleForm.count" placeholder="Activity count" :options="options" />
    </bk-form-item>
    <bk-form-item label="Activity time" required>
      <el-col :span="11">
        <bk-form-item prop="date1">
          <el-date-picker
            v-model="ruleForm.date1"
            type="date"
            aria-label="Pick a date"
            placeholder="Pick a date"
            style="width: 100%"
          />
        </bk-form-item>
      </el-col>
      <el-col class="text-center" :span="2">
        <span class="text-gray-500">-</span>
      </el-col>
      <el-col :span="11">
        <bk-form-item prop="date2">
          <el-time-picker
            v-model="ruleForm.date2"
            aria-label="Pick a time"
            placeholder="Pick a time"
            style="width: 100%"
          />
        </bk-form-item>
      </el-col>
    </bk-form-item>
    <bk-form-item label="Instant delivery" prop="delivery">
      <el-switch v-model="ruleForm.delivery" />
    </bk-form-item>
    <bk-form-item label="Activity location" prop="location">
      <el-segmented v-model="ruleForm.location" :options="locationOptions" />
    </bk-form-item>
    <bk-form-item label="Activity type" prop="type">
      <el-checkbox-group v-model="ruleForm.type">
        <el-checkbox value="Online activities" name="type"> Online activities </el-checkbox>
        <el-checkbox value="Promotion activities" name="type"> Promotion activities </el-checkbox>
        <el-checkbox value="Offline activities" name="type"> Offline activities </el-checkbox>
        <el-checkbox value="Simple brand exposure" name="type"> Simple brand exposure </el-checkbox>
      </el-checkbox-group>
    </bk-form-item>
    <bk-form-item label="Resources" prop="resource">
      <el-radio-group v-model="ruleForm.resource">
        <el-radio value="Sponsorship">Sponsorship</el-radio>
        <el-radio value="Venue">Venue</el-radio>
      </el-radio-group>
    </bk-form-item>
    <bk-form-item label="Activity form" prop="desc">
      <el-input v-model="ruleForm.desc" type="textarea" />
    </bk-form-item>
    <bk-form-item>
      <bk-button type="primary" @click="submitForm(ruleFormRef)"> Create </bk-button>
      <bk-button @click="resetForm(ruleFormRef)">Reset</bk-button>
    </bk-form-item>
  </bk-form>
</template>

<script lang="ts" setup>
import { reactive, ref } from "vue"
import type { FormInstance, FormRules } from "vue-business-kit"

interface RuleForm {
  name: string
  region: string
  count: string
  date1: string
  date2: string
  delivery: boolean
  location: string
  type: string[]
  resource: string
  desc: string
}

const ruleFormRef = ref<FormInstance>()
const ruleForm = reactive<RuleForm>({
  name: "Hello",
  region: "",
  count: "",
  date1: "",
  date2: "",
  delivery: false,
  location: "",
  type: [],
  resource: "",
  desc: ""
})

const locationOptions = ["Home", "Company", "School"]

const rules = reactive<FormRules<RuleForm>>({
  name: [
    { required: true, message: "Please input Activity name", trigger: "blur" },
    { min: 3, max: 5, message: "Length should be 3 to 5", trigger: "blur" }
  ],
  region: [
    {
      required: true,
      message: "Please select Activity zone",
      trigger: "change"
    }
  ],
  count: [
    {
      required: true,
      message: "Please select Activity count",
      trigger: "change"
    }
  ],
  date1: [
    {
      type: "date",
      required: true,
      message: "Please pick a date",
      trigger: "change"
    }
  ],
  date2: [
    {
      type: "date",
      required: true,
      message: "Please pick a time",
      trigger: "change"
    }
  ],
  location: [
    {
      required: true,
      message: "Please select a location",
      trigger: "change"
    }
  ],
  type: [
    {
      type: "array",
      required: true,
      message: "Please select at least one activity type",
      trigger: "change"
    }
  ],
  resource: [
    {
      required: true,
      message: "Please select activity resource",
      trigger: "change"
    }
  ],
  desc: [{ required: true, message: "Please input activity form", trigger: "blur" }]
})

const submitForm = async (formEl: FormInstance | undefined) => {
  if (!formEl) return
  await formEl.elFormRef?.validate((valid, fields) => {
    if (valid) {
      console.log("submit!")
    } else {
      console.log("error submit!", fields)
    }
  })
}

const resetForm = (formEl: FormInstance | undefined) => {
  if (!formEl) return
  formEl.elFormRef?.resetFields()
}

const options = Array.from({ length: 10000 }).map((_, idx) => ({
  value: `${idx + 1}`,
  label: `${idx + 1}`
}))
</script>

Custom Validation Rules

This example shows how to customize your own validation rules to finish a two-factor password verification.

Here we use status-icon to reflect validation result as an icon.

vue

<template>
  <bk-form
    ref="ruleFormRef"
    style="max-width: 600px"
    :model="ruleForm"
    :rules="rules"
    label-width="auto"
    status-icon
    class="demo-ruleForm"
  >
    <bk-form-item label="Password" prop="pass">
      <el-input v-model="ruleForm.pass" type="password" autocomplete="off" />
    </bk-form-item>
    <bk-form-item label="Confirm" prop="checkPass">
      <el-input v-model="ruleForm.checkPass" type="password" autocomplete="off" />
    </bk-form-item>
    <bk-form-item label="Age" prop="age">
      <el-input v-model.number="ruleForm.age" />
    </bk-form-item>
    <bk-form-item>
      <bk-button type="primary" @click="submitForm(ruleFormRef)"> Create </bk-button>
      <bk-button @click="resetForm(ruleFormRef)">Reset</bk-button>
    </bk-form-item>
  </bk-form>
</template>

<script lang="ts" setup>
import { reactive, ref } from "vue"

import type { FormInstance, FormRules } from "vue-business-kit"

const ruleFormRef = ref<FormInstance>()

const checkAge = (rule: any, value: any, callback: any) => {
  if (!value) {
    return callback(new Error("Please input the age"))
  }
  setTimeout(() => {
    if (!Number.isInteger(value)) {
      callback(new Error("Please input digits"))
    } else {
      if (value < 18) {
        callback(new Error("Age must be greater than 18"))
      } else {
        callback()
      }
    }
  }, 1000)
}

const validatePass = (rule: any, value: any, callback: any) => {
  if (value === "") {
    callback(new Error("Please input the password"))
  } else {
    if (ruleForm.checkPass !== "") {
      if (!ruleFormRef.value) return
      ruleFormRef.value.elFormRef?.validateField("checkPass")
    }
    callback()
  }
}
const validatePass2 = (rule: any, value: any, callback: any) => {
  if (value === "") {
    callback(new Error("Please input the password again"))
  } else if (value !== ruleForm.pass) {
    callback(new Error("Two inputs don't match!"))
  } else {
    callback()
  }
}

const ruleForm = reactive({
  pass: "",
  checkPass: "",
  age: ""
})

const rules = reactive<FormRules<typeof ruleForm>>({
  pass: [{ validator: validatePass, trigger: "blur" }],
  checkPass: [{ validator: validatePass2, trigger: "blur" }],
  age: [{ validator: checkAge, trigger: "blur" }]
})

const submitForm = (formEl: FormInstance | undefined) => {
  if (!formEl) return
  formEl.elFormRef?.validate((valid) => {
    if (valid) {
      console.log("submit!")
    } else {
      console.log("error submit!")
    }
  })
}

const resetForm = (formEl: FormInstance | undefined) => {
  if (!formEl) return
  formEl.elFormRef?.resetFields()
}
</script>

TIP

Custom validate callback function must be called. See more advanced usage at async-validator.

Add/Delete Form Item

In addition to passing all validation rules at once on the form component, you can also pass the validation rules or delete rules on a single form field dynamically.

vue

<template>
  <bk-form
    ref="formRef"
    :model="dynamicValidateForm"
    label-width="auto"
    style="max-width: 600px"
    class="demo-dynamic"
  >
    <bk-form-item
      prop="email"
      label="Email"
      :rules="[
        {
          required: true,
          message: 'Please input email address',
          trigger: 'blur'
        },
        {
          type: 'email',
          message: 'Please input correct email address',
          trigger: ['blur', 'change']
        }
      ]"
    >
      <el-input v-model="dynamicValidateForm.email" />
    </bk-form-item>
    <bk-form-item
      v-for="(domain, index) in dynamicValidateForm.domains"
      :key="domain.key"
      :label="'Domain' + index"
      :prop="'domains.' + index + '.value'"
      :rules="{
        required: true,
        message: 'domain can not be null',
        trigger: 'blur'
      }"
    >
      <el-input v-model="domain.value" />
      <bk-button class="mt-2" @click.prevent="removeDomain(domain)"> Delete </bk-button>
    </bk-form-item>
    <bk-form-item>
      <bk-button type="primary" @click="submitForm(formRef)">Submit</bk-button>
      <bk-button @click="addDomain">New domain</bk-button>
      <bk-button @click="resetForm(formRef)">Reset</bk-button>
    </bk-form-item>
  </bk-form>
</template>

<script lang="ts" setup>
import { reactive, ref } from "vue"

import type { FormInstance } from "vue-business-kit"

const formRef = ref<FormInstance>()
const dynamicValidateForm = reactive<{
  domains: DomainItem[]
  email: string
}>({
  domains: [
    {
      key: 1,
      value: ""
    }
  ],
  email: ""
})

interface DomainItem {
  key: number
  value: string
}

const removeDomain = (item: DomainItem) => {
  const index = dynamicValidateForm.domains.indexOf(item)
  if (index !== -1) {
    dynamicValidateForm.domains.splice(index, 1)
  }
}

const addDomain = () => {
  dynamicValidateForm.domains.push({
    key: Date.now(),
    value: ""
  })
}

const submitForm = (formEl: FormInstance | undefined) => {
  if (!formEl) return
  formEl.elFormRef?.validate((valid) => {
    if (valid) {
      console.log("submit!")
    } else {
      console.log("error submit!")
    }
  })
}

const resetForm = (formEl: FormInstance | undefined) => {
  if (!formEl) return
  formEl.elFormRef?.resetFields()
}
</script>

Number Validate

Number Validate need a .number modifier added on the input v-model binding，it's used to transform the string value to the number which is provided by Vue.

TIP

When a form item is nested within another form item, its label width is set to 0. If necessary, you can manually set the label-width attribute on the nested form item.

Size Control

All components in a Form inherit their size attribute from that Form. Similarly, FormItem also has a size attribute.

Still you can fine tune each component's size if you don't want that component to inherit its size from From or FormItem.

vue

<template>
  <div>
    <el-radio-group v-model="size" aria-label="size control">
      <el-radio-button value="large">large</el-radio-button>
      <el-radio-button value="default">default</el-radio-button>
      <el-radio-button value="small">small</el-radio-button>
    </el-radio-group>
    <el-radio-group v-model="labelPosition" aria-label="position control">
      <el-radio-button value="left">Left</el-radio-button>
      <el-radio-button value="right">Right</el-radio-button>
      <el-radio-button value="top">Top</el-radio-button>
    </el-radio-group>
  </div>
  <br />
  <bk-form
    style="max-width: 600px"
    :model="sizeForm"
    label-width="auto"
    :label-position="labelPosition"
    :size="size"
  >
    <bk-form-item label="Activity name">
      <el-input v-model="sizeForm.name" />
    </bk-form-item>
    <bk-form-item label="Activity zone">
      <el-select v-model="sizeForm.region" placeholder="please select your zone">
        <el-option label="Zone one" value="shanghai" />
        <el-option label="Zone two" value="beijing" />
      </el-select>
    </bk-form-item>
    <bk-form-item label="Activity time">
      <el-col :span="11">
        <el-date-picker
          v-model="sizeForm.date1"
          type="date"
          aria-label="Pick a date"
          placeholder="Pick a date"
          style="width: 100%"
        />
      </el-col>
      <el-col class="text-center" :span="1" style="margin: 0 0.5rem">-</el-col>
      <el-col :span="11">
        <el-time-picker
          v-model="sizeForm.date2"
          aria-label="Pick a time"
          placeholder="Pick a time"
          style="width: 100%"
        />
      </el-col>
    </bk-form-item>
    <bk-form-item label="Activity type">
      <el-checkbox-group v-model="sizeForm.type">
        <el-checkbox-button value="Online activities" name="type">
          Online activities
        </el-checkbox-button>
        <el-checkbox-button value="Promotion activities" name="type">
          Promotion activities
        </el-checkbox-button>
      </el-checkbox-group>
    </bk-form-item>
    <bk-form-item label="Resources">
      <el-radio-group v-model="sizeForm.resource">
        <el-radio border value="Sponsor">Sponsor</el-radio>
        <el-radio border value="Venue">Venue</el-radio>
      </el-radio-group>
    </bk-form-item>
    <bk-form-item>
      <bk-button type="primary" @click="onSubmit">Create</bk-button>
      <bk-button>Cancel</bk-button>
    </bk-form-item>
  </bk-form>
</template>

<script lang="ts" setup>
import { reactive, ref } from "vue"

import type { ComponentSize, FormProps } from "vue-business-kit"

const size = ref<ComponentSize>("default")
const labelPosition = ref<FormProps["labelPosition"]>("right")

const sizeForm = reactive({
  name: "",
  region: "",
  date1: "",
  date2: "",
  delivery: false,
  type: [],
  resource: "",
  desc: ""
})

function onSubmit() {
  console.log("submit!")
}
</script>

<style>
.el-radio-group {
  margin-right: 12px;
}
</style>

Accessibility

When only a single input (or related control such as select or checkbox) is inside of a form item, the form item's label will automatically be attached to that input. However, if multiple inputs are inside of the form item, the form item will be assigned the WAI-ARIA role of group instead. In this case, it is your responsibility to assign assistive labels to the individual inputs.

Form API

Form Attributes

Name	Description	Type	Default
items	Configuration array for form items, each item can specify type, componentProps, and children	`array`	—
colNum	Number of columns for multi-column form layout	`number`	1

Element Plus Form Attributes

Name	Description	Type	Default
model	Data of form component.	`object`	—
rules	Validation rules of form.	`object`	—
inline	Whether the form is inline. (It is recommended to use the `col-num` attribute)	`boolean`	false
label-position	Position of label. If set to `'left'` or `'right'`, `label-width` prop is also required.	`enum`	right
label-width	Width of label, e.g. `'50px'`. All its direct child form items will inherit this value. `auto` is supported.	`string` / `number`	''
label-suffix	Suffix of the label.	`string`	''
hide-required-asterisk	Whether to hide required fields should have a red asterisk (star) beside their labels.	`boolean`	false
require-asterisk-position	Position of asterisk.	`enum`	left
show-message	Whether to show the error message.	`boolean`	true
inline-message	Whether to display the error message inline with the form item.	`boolean`	false
status-icon	Whether to display an icon indicating the validation result.	`boolean`	false
validate-on-rule-change	Whether to trigger validation when the `rules` prop is changed.	`boolean`	true
size	Control the size of components in this form.	`enum`	—
disabled	Whether to disable all components in this form. If set to `true`, it will override the `disabled` prop of the inner component.	`boolean`	false
scroll-to-error	When validation fails, scroll to the first error form entry.	`boolean`	false
scroll-into-view-options	When validation fails, it scrolls to the first error item based on the scrollIntoView option. scrollIntoView.	`object` / `boolean`	true

FormItem

Extends all Element Plus FormItemProps properties with additional features:

Name	Description	Type	Default
type required	Type of the form item component (e.g., 'input', 'select', 'radio')	`string`	—
componentProps	Additional props to pass to the underlying component	`object`	—
children	Nested form items for complex layouts	`array`	—

Form Events

Element Plus Form Events

Name	Description	Type
validate	triggers after a form item is validated	`Function`

Form Slots

Element Plus Form Slots

Name	Description	Subtags
default	customize default content	FormItem

Form Exposes

Element Plus Form Exposes

Name	Description	Type
validate	Validate the whole form. Receives a callback or returns `Promise`.	`Function`
validateField	Validate specified fields.	`Function`
resetFields	Reset specified fields and remove validation result.	`Function`
scrollToField	Scroll to the specified fields.	`Function`
clearValidate	Clear validation messages for all or specified fields.	`Function`
fields	Get all fields context.	`array`
getField	Get a field context.	`Function`

FormItem API

FormItem Attributes

Element Plus FormItem Attributes

Name	Description	Type	Default
prop	A key of `model`. It could be a path of the property (e.g `a.b.0` or `['a', 'b', '0']`). In the use of `validate` and `resetFields` method, the attribute is required.	`string` / `string[]`	—
label	Label text.	`string`	—
label-position	Position of item label. If set to `'left'` or `'right'`, `label-width` prop is also required. Default extend `label-position` of `form`.	`enum`	''
label-width	Width of label, e.g. `'50px'`. `'auto'` is supported.	`string` / `number`	—
required	Whether the field is required or not, will be determined by validation rules if omitted.	`boolean`	—
rules	Validation rules of form, see the following table, more advanced usage at async-validator.	`object`	—
error	Field error message, set its value and the field will validate error and show this message immediately.	`string`	—
show-message	Whether to show the error message.	`boolean`	true
inline-message	Inline style validate message.	`boolean`	false
size	Control the size of components in this form-item.	`enum`	—
for	Same as for in native label.	`string`	—
validate-status	Validation state of formItem.	`enum`	—

FormItemRule

Element Plus FormItemRule

Name	Description	Type	Default
trigger	How the validator is triggered.	`enum`	—

TIP

If you don't want to trigger the validator based on input events, set the validate-event attribute as false on the corresponding input type components (<el-input>, <el-radio>, <el-select>, ...).

FormItem Slots

Element Plus FormItem Slots

Name	Description	Type
default	Content of Form Item.	—
label	Custom content to display on label.	`object`
error	Custom content to display validation message.	`object`

FormItem Exposes

Element Plus FormItem Exposes

Name	Description	Type
size	Form item size.	`object`
validateMessage	Validation message.	`object`
validateState	Validation state.	`object`
validate	Validate form item.	`Function`
resetField	Reset current field and remove validation result.	`Function`
clearValidate	Remove validation status of the field.	`Function`

Form ​

Basic Usage ​

Multi-Column Form @items ​

Alignment ​

Validation ​

Custom Validation Rules ​

Add/Delete Form Item ​

Number Validate ​

Size Control ​

Accessibility ​

Form API ​

Form Attributes ​

FormItem ​

Form Events ​

Form Slots ​

Form Exposes ​

FormItem API ​

FormItem Attributes ​

FormItemRule ​

FormItem Slots ​

FormItem Exposes ​