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API > @angular/forms

FormControl

跟踪独立表单控件的值和验证状态。

Tracks the value and validation status of an individual form control.

查看"说明"...

      
      class FormControl extends AbstractControl {
  constructor(formState: any = null, validatorOrOpts?: ValidatorFn | AbstractControlOptions | ValidatorFn[], asyncValidator?: AsyncValidatorFn | AsyncValidatorFn[])
  setValue(value: any, options: { onlySelf?: boolean; emitEvent?: boolean; emitModelToViewChange?: boolean; emitViewToModelChange?: boolean; } = {}): void
  patchValue(value: any, options: { onlySelf?: boolean; emitEvent?: boolean; emitModelToViewChange?: boolean; emitViewToModelChange?: boolean; } = {}): void
  reset(formState: any = null, options: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
  registerOnChange(fn: Function): void
  registerOnDisabledChange(fn: (isDisabled: boolean) => void): void

  // 继承自 forms/AbstractControl
  constructor(validators: ValidatorFn | ValidatorFn[], asyncValidators: AsyncValidatorFn | AsyncValidatorFn[])
  value: any
  validator: ValidatorFn | null
  asyncValidator: AsyncValidatorFn | null
  parent: FormGroup | FormArray | null
  status: string
  valid: boolean
  invalid: boolean
  pending: boolean
  disabled: boolean
  enabled: boolean
  errors: ValidationErrors | null
  pristine: boolean
  dirty: boolean
  touched: boolean
  untouched: boolean
  valueChanges: Observable<any>
  statusChanges: Observable<any>
  updateOn: FormHooks
  root: AbstractControl
  setValidators(newValidator: ValidatorFn | ValidatorFn[]): void
  setAsyncValidators(newValidator: AsyncValidatorFn | AsyncValidatorFn[]): void
  clearValidators(): void
  clearAsyncValidators(): void
  markAsTouched(opts: { onlySelf?: boolean; } = {}): void
  markAllAsTouched(): void
  markAsUntouched(opts: { onlySelf?: boolean; } = {}): void
  markAsDirty(opts: { onlySelf?: boolean; } = {}): void
  markAsPristine(opts: { onlySelf?: boolean; } = {}): void
  markAsPending(opts: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
  disable(opts: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
  enable(opts: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
  setParent(parent: FormGroup | FormArray): void
  abstract setValue(value: any, options?: Object): void
  abstract patchValue(value: any, options?: Object): void
  abstract reset(value?: any, options?: Object): void
  updateValueAndValidity(opts: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
  setErrors(errors: ValidationErrors, opts: { emitEvent?: boolean; } = {}): void
  get(path: string | (string | number)[]): AbstractControl | null
  getError(errorCode: string, path?: string | (string | number)[]): any
  hasError(errorCode: string, path?: string | (string | number)[]): boolean
}

参见

说明

它和 FormGroup 和 FormArray 是 Angular 表单的三大基本构造块之一。 它扩展了 AbstractControl 类，并实现了关于访问值、验证状态、用户交互和事件的大部分基本功能。

This is one of the three fundamental building blocks of Angular forms, along with FormGroup and FormArray. It extends the AbstractControl class that implements most of the base functionality for accessing the value, validation status, user interactions and events. See usage examples below.

Further information available in the Usage Notes...

构造函数

创建新的 FormControl 实例。

Creates a new FormControl instance.

      
      constructor(formState: any = null, validatorOrOpts?: ValidatorFn | AbstractControlOptions | ValidatorFn[], asyncValidator?: AsyncValidatorFn | AsyncValidatorFn[])
参数
formState any

使用一个初始值或定义了初始值和禁用状态的对象初始化该控件。

Initializes the control with an initial value, or an object that defines the initial value and disabled state.

可选. 默认值是 `null`.
validatorOrOpts ValidatorFn | AbstractControlOptions | ValidatorFn[]

一个同步验证器函数或其数组，或者一个包含验证函数和验证触发器的 AbstractControlOptions 对象。

A synchronous validator function, or an array of such functions, or an AbstractControlOptions object that contains validation functions and a validation trigger.

可选. 默认值是 `undefined`.
asyncValidator AsyncValidatorFn | AsyncValidatorFn[]

一个异步验证器函数或其数组。

A single async validator or array of async validator functions

可选. 默认值是 `undefined`.

方法

setValue()

设置该表单控件的新值。

Sets a new value for the form control.

      
      setValue(value: any, options: { onlySelf?: boolean; emitEvent?: boolean; emitModelToViewChange?: boolean; emitViewToModelChange?: boolean; } = {}): void
参数
value any

控件的新值。

The new value for the control.

options object

当值发生变化时，该配置项决定如何传播变更以及发出事件。 该配置项会传递给 updateValueAndValidity 方法。

Configuration options that determine how the control propagates changes and emits events when the value changes. The configuration options are passed to the updateValueAndValidity method.

  • onlySelf：如果为 true，则每次变更只影响该控件本身，不影响其父控件。默认为 false。

    onlySelf: When true, each change only affects this control, and not its parent. Default is false.

  • emitEvent：如果为 true 或未提供（默认），则当控件值变化时， statusChanges 和 valueChanges 这两个 Observable 都会以最近的状态和值发出事件。 如果为 false，则不会发出事件。

    emitEvent: When true or not supplied (the default), both the statusChanges and valueChanges observables emit events with the latest status and value when the control value is updated. When false, no events are emitted.

  • emitModelToViewChange：如果为 true 或未提供（默认），则每次变化都会触发一个 onChange 事件以更新视图。

    emitModelToViewChange: When true or not supplied (the default), each change triggers an onChange event to update the view.

  • emitViewToModelChange：如果为 true 或未提供（默认），则每次变化都会触发一个 ngModelChange 事件以更新模型。

    emitViewToModelChange: When true or not supplied (the default), each change triggers an ngModelChange event to update the model.

可选. 默认值是 `{}`.
返回值

void

patchValue()

修补控件的值。

Patches the value of a control.

See also:

  • setValue 的配置项

    setValue for options

      
      patchValue(value: any, options: { onlySelf?: boolean; emitEvent?: boolean; emitModelToViewChange?: boolean; emitViewToModelChange?: boolean; } = {}): void
参数
value any
options object
可选. 默认值是 `{}`.
返回值

void

在 FormControl 这个层次上，该函数的功能和 setValue 完全相同。 但 FormGroup 和 FormArray 上的 patchValue 则具有不同的行为。

This function is functionally the same as setValue at this level. It exists for symmetry with patchValue on FormGroups and FormArrays, where it does behave differently.

reset()

重置该表单控件，把它标记为 pristine 和 untouched，并把它的值设置为 null。

Resets the form control, marking it pristine and untouched, and setting the value to null.

      
      reset(formState: any = null, options: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
参数
formState any

使用初始值或一个包含初始值和禁用状态的对象来重置该控件。

Resets the control with an initial value, or an object that defines the initial value and disabled state.

可选. 默认值是 `null`.
options object

当值发生变化时，该配置项会决定控件如何传播变更以及发出事件。

Configuration options that determine how the control propagates changes and emits events after the value changes.

  • onlySelf：如果为 true ，则每个变更只会影响当前控件而不会影响父控件。默认为 false。

    onlySelf: When true, each change only affects this control, and not its parent. Default is false.

  • emitEvent：如果为 true 或未提供（默认），则当控件被重置时， statusChanges 和 valueChanges 这两个 Observable 都会以最近的状态和值发出事件。 如果为 false，则不会发出事件。

    emitEvent: When true or not supplied (the default), both the statusChanges and valueChanges observables emit events with the latest status and value when the control is reset. When false, no events are emitted.

可选. 默认值是 `{}`.
返回值

void

registerOnChange()

注册变更事件的监听器。

Register a listener for change events.

      
      registerOnChange(fn: Function): void
参数
fn Function

当值变化时，就会调用该方法。

The method that is called when the value changes

返回值

void

registerOnDisabledChange()

注册禁用事件的监听器。

Register a listener for disabled events.

      
      registerOnDisabledChange(fn: (isDisabled: boolean) => void): void
参数
fn (isDisabled: boolean) => void

当禁用状态发生变化时，就会调用该方法。

The method that is called when the disabled status changes.

返回值

void

使用说明

初始化表单控件

Initializing Form Controls

用一个初始值初始化 FormControl。

Instantiate a FormControl, with an initial value.

      
      const control = new FormControl('some value');
console.log(control.value);     // 'some value'

下面的例子用一个表单状态对象初始化控件。这里用到的是 value 和 disabled 键。

The following example initializes the control with a form state object. The value and disabled keys are required in this case.

      
      const control = new FormControl({ value: 'n/a', disabled: true });
console.log(control.value);     // 'n/a'
console.log(control.status);    // 'DISABLED'

下面的例子使用一个同步验证器初始化了该控件。

The following example initializes the control with a sync validator.

      
      const control = new FormControl('', Validators.required);
console.log(control.value);      // ''
console.log(control.status);     // 'INVALID'

下面的例子使用一个配置对象初始化了该控件。

The following example initializes the control using an options object.

      
      const control = new FormControl('', {
   validators: Validators.required,
   asyncValidators: myAsyncValidator
});

配置该控件，使其在发生 blur 事件时更新

Configure the control to update on a blur event

把 updateOn 选项设置为 'blur'，可以在发生 blur 事件时更新。

Set the updateOn option to 'blur' to update on the blur event.

      
      const control = new FormControl('', { updateOn: 'blur' });

配置该控件，使其在发生 submit 事件时更新

Configure the control to update on a submit event

把 updateOn 选项设置为 'submit'，可以在发生 submit 事件时更新。

Set the updateOn option to 'submit' to update on a submit event.

      
      const control = new FormControl('', { updateOn: 'submit' });

把该控件重置回初始值

Reset the control back to an initial value

通过传递包含值和禁用状态的独立值或表单状态对象，可以将其重置为特定的表单状态（这是所支持的仅有的两个非计算状态）。

You reset to a specific form state by passing through a standalone value or a form state object that contains both a value and a disabled state (these are the only two properties that cannot be calculated).

      
      const control = new FormControl('Nancy');

console.log(control.value); // 'Nancy'

control.reset('Drew');

console.log(control.value); // 'Drew'

把该控件重置回初始值并禁用。

Reset the control back to an initial value and disabled

      
      const control = new FormControl('Nancy');

console.log(control.value); // 'Nancy'
console.log(control.status); // 'VALID'

control.reset({ value: 'Drew', disabled: true });

console.log(control.value); // 'Drew'
console.log(control.status); // 'DISABLED'