element-plus/docs/en-US/component/message-box.md
JeremyWuuuuu 11d3db586c
feat(components): [el-messagebox] add context for message box (#6379)
- Add context for message box
- Update documentation based on changes
2022-03-05 19:40:35 +08:00

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Message Box

A set of modal boxes simulating system message box, mainly for alerting information, confirm operations and prompting messages.

:::tip

By design MessageBox provides simulations of system's alert, confirm and promptso it's content should be simple. For more complicated contents, please use Dialog.

:::

Alert

Alert interrupts user operation until the user confirms.

:::demo Open an alert by calling the $alert method. It simulates the system's alert, and cannot be closed by pressing ESC or clicking outside the box. In this example, two parameters message and title are received. It is worth mentioning that when the box is closed, it returns a Promise object for further processing. If you are not sure if your target browsers support Promise, you should import a third party polyfill or use callbacks instead like this example.

message-box/alert

:::

Confirm

Confirm is used to ask users' confirmation.

:::demo Call $confirm method to open a confirm, and it simulates the system's confirm. We can also highly customize Message Box by passing a third attribute options which is a literal object. The attribute type indicates the message type, and it's value can be success, error, info and warning. Note that the second attribute title must be a string, and if it is an object, it will be handled as the attribute options. Here we use Promise to handle further processing.

message-box/confirm

:::

Prompt

Prompt is used when user input is required.

:::demo Call $prompt method to open a prompt, and it simulates the system's prompt. You can use inputPattern parameter to specify your own RegExp pattern. Use inputValidator to specify validation method, and it should return Boolean or String. Returning false or String means the validation has failed, and the string returned will be used as the inputErrorMessage. In addition, you can customize the placeholder of the input box with inputPlaceholder parameter.

message-box/prompt

:::

Customization

Can be customized to show various content.

:::demo The three methods mentioned above are repackagings of the $msgbox method. This example calls $msgbox method directly using the showCancelButton attribute, which is used to indicate if a cancel button is displayed. Besides we can use cancelButtonClass to add a custom style and cancelButtonText to customize the button text (the confirm button also has these fields, and a complete list of fields can be found at the end of this documentation). This example also uses the beforeClose attribute. It is a method and will be triggered when the MessageBox instance will be closed, and its execution will stop the instance from closing. It has three parameters: action, instance and done. Using it enables you to manipulate the instance before it closes, e.g. activating loading for confirm button; you can invoke the done method to close the MessageBox instance (if done is not called inside beforeClose, the instance will not be closed).

message-box/customization

:::

:::tip

The content of MessageBox can be VNode, allowing us to pass custom components. When opening the MessageBox, Vue compares new VNode with old VNode, then figures out how to efficiently update the UI, so the components may not be completely re-rendered (#8931). In this case, you can add a unique key to VNode each time MessageBox opens: example.

:::

Use HTML String

message supports HTML string.

:::demo Set dangerouslyUseHTMLString to true and message will be treated as an HTML string.

message-box/use-html

:::

:::warning

Although message property supports HTML strings, dynamically rendering arbitrary HTML on your website can be very dangerous because it can easily lead to XSS attacks. So when dangerouslyUseHTMLString is on, please make sure the content of message is trusted, and never assign message to user-provided content.

:::

Distinguishing cancel and close

In some cases, clicking the cancel button and close button may have different meanings.

:::demo By default, the parameters of Promise's reject callback and callback are 'cancel' when the user cancels (clicking the cancel button) and closes (clicking the close button or mask layer, pressing the ESC key) the MessageBox. If distinguishCancelAndClose is set to true, the parameters of the above two operations are 'cancel' and 'close' respectively.

message-box/distinguishable-close-cancel

:::

Centered content

Content of MessageBox can be centered.

:::demo Setting center to true will center the content.

message-box/centered-content

:::

Draggable

MessageBox can be draggable.

:::demo Setting draggable to true allows user to drag MessageBox.

message-box/draggable

:::

Global method

If Element Plus is fully imported, it will add the following global methods for app.config.globalProperties: $msgbox, $alert, $confirm and $prompt. So in a Vue instance you can call MessageBox like what we did in this page. The parameters are:

  • $msgbox(options)
  • $alert(message, title, options) or $alert(message, options)
  • $confirm(message, title, options) or $confirm(message, options)
  • $prompt(message, title, options) or $prompt(message, options)

App context inheritance > 2.0.4

Now message box accepts a context as second (forth if you are using message box variants) parameter of the message constructor which allows you to inject current app's context to message which allows you to inherit all the properties of the app.

import { getCurrentInstance } from 'vue'
import { ElMessageBox } from 'element-plus'

// in your setup method
const { appContext } = getCurrentInstance()!
// You can pass it like:
ElMessageBox({}, appContext)
// or if you are using variants
ElMessageBox.alert('Hello world!', 'Title', {}, appContext)

Local import

If you prefer importing MessageBox on demand:

import { ElMessageBox } from 'element-plus'

The corresponding methods are: ElMessageBox, ElMessageBox.alert, ElMessageBox.confirm and ElMessageBox.prompt. The parameters are the same as above.

Options

Attribute Description Type Accepted Values Default
title title of the MessageBox string
message content of the MessageBox string
dangerouslyUseHTMLString whether message is treated as HTML string boolean false
type message type, used for icon display string success / info / warning / error
icon custom icon component, overrides type string / Component
custom-class custom class name for MessageBox string
custom-style custom inline style for MessageBox CSSProperties
callback MessageBox closing callback if you don't prefer Promise function(action), where action can be 'confirm', 'cancel' or 'close', and instance is the MessageBox instance. You can access to that instance's attributes and methods
showClose whether to show close icon of MessageBox boolean true
before-close callback before MessageBox closes, and it will prevent MessageBox from closing function(action, instance, done), where action can be 'confirm', 'cancel' or 'close'; instance is the MessageBox instance, and you can access to that instance's attributes and methods; done is for closing the instance
distinguish-cancel-and-close whether to distinguish canceling and closing the MessageBox boolean false
lock-scroll whether to lock body scroll when MessageBox prompts boolean true
show-cancel-button whether to show a cancel button boolean false (true when called with confirm and prompt)
show-confirm-button whether to show a confirm button boolean true
cancel-button-text text content of cancel button string Cancel
confirm-button-text text content of confirm button string OK
cancel-button-class custom class name of cancel button string
confirm-button-class custom class name of confirm button string
close-on-click-modal whether MessageBox can be closed by clicking the mask boolean true (false when called with alert)
close-on-press-escape whether MessageBox can be closed by pressing the ESC boolean true (false when called with alert)
close-on-hash-change whether to close MessageBox when hash changes boolean true
show-input whether to show an input boolean false (true when called with prompt)
input-placeholder placeholder of input string
input-type type of input string text
input-value initial value of input string
input-pattern regexp for the input regexp
input-validator validation function for the input. Should returns a boolean or string. If a string is returned, it will be assigned to inputErrorMessage function
input-error-message error message when validation fails string Illegal input
center whether to align the content in center boolean false
draggable whether MessageBox is draggable boolean false
round-button whether to use round button boolean false
button-size custom size of confirm and cancel buttons string small / default / large default