在Angular项目中,可以使用NgRx来管理应用程序的状态。当处理表单时,可以使用NGRX动作来处理表单的依赖关系。下面是一个示例解决方法:
首先,安装必要的依赖项。在命令行中运行以下命令:
npm install @ngrx/store @ngrx/effects --save
然后,创建一个名为form.actions.ts
的文件,并添加以下代码:
import { createAction, props } from '@ngrx/store';
export const loadForm = createAction('[Form] Load Form');
export const loadFormSuccess = createAction('[Form] Load Form Success', props<{ form: any }>());
export const loadFormFailure = createAction('[Form] Load Form Failure', props<{ error: any }>());
export const updateForm = createAction('[Form] Update Form', props<{ form: any }>());
export const submitForm = createAction('[Form] Submit Form', props<{ form: any }>());
export const submitFormSuccess = createAction('[Form] Submit Form Success');
export const submitFormFailure = createAction('[Form] Submit Form Failure', props<{ error: any }>());
然后,创建一个名为form.reducer.ts
的文件,并添加以下代码:
import { createReducer, on } from '@ngrx/store';
import * as FormActions from './form.actions';
export interface FormState {
form: any;
loading: boolean;
error: any;
}
export const initialState: FormState = {
form: null,
loading: false,
error: null
};
export const formReducer = createReducer(
initialState,
on(FormActions.loadForm, state => ({
...state,
loading: true,
error: null
})),
on(FormActions.loadFormSuccess, (state, { form }) => ({
...state,
form,
loading: false
})),
on(FormActions.loadFormFailure, (state, { error }) => ({
...state,
error,
loading: false
})),
on(FormActions.updateForm, (state, { form }) => ({
...state,
form
})),
on(FormActions.submitForm, state => ({
...state,
loading: true,
error: null
})),
on(FormActions.submitFormSuccess, state => ({
...state,
loading: false
})),
on(FormActions.submitFormFailure, (state, { error }) => ({
...state,
error,
loading: false
}))
);
接下来,创建一个名为form.effects.ts
的文件,并添加以下代码:
import { Injectable } from '@angular/core';
import { Actions, createEffect, ofType } from '@ngrx/effects';
import { of } from 'rxjs';
import { catchError, map, mergeMap } from 'rxjs/operators';
import * as FormActions from './form.actions';
import { FormService } from './form.service';
@Injectable()
export class FormEffects {
loadForm$ = createEffect(() =>
this.actions$.pipe(
ofType(FormActions.loadForm),
mergeMap(() =>
this.formService.getForm().pipe(
map(form => FormActions.loadFormSuccess({ form })),
catchError(error => of(FormActions.loadFormFailure({ error })))
)
)
)
);
submitForm$ = createEffect(() =>
this.actions$.pipe(
ofType(FormActions.submitForm),
mergeMap(({ form }) =>
this.formService.submitForm(form).pipe(
map(() => FormActions.submitFormSuccess()),
catchError(error => of(FormActions.submitFormFailure({ error })))
)
)
)
);
constructor(
private actions$: Actions,
private formService: FormService
) {}
}
然后,创建一个名为form.service.ts
的文件,并添加以下代码:
import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';
@Injectable({
providedIn: 'root'
})
export class FormService {
constructor(private http: HttpClient) {}
getForm(): Observable {
return this.http.get('api/form');
}
submitForm(form: any): Observable {
return this.http.post('api/submit', form);
}
}
最后,在需要使用表单的组件中,添加以下代码:
import { Component, OnInit } from '@angular/core';
import { Store } from '@ngrx/store';
import { Observable } from 'rxjs';
import * as FormActions from './form.actions';
import { FormState } from './form.reducer';
@Component({
selector: 'app