angular - 返回错误类型错误的角度反应形式：“

问题描述

我正在尝试在 Angular 中创建一个反应式表单，但是在浏览器上加载页面时它返回两个错误ERROR TypeError: "_co.createBlogForm.form is undefined"和ERROR TypeError: "_co.blogTitle is undefined"在控制台上. 在组件内部，我使用 formControlName 声明了所有变量，并将 FormGroup 与表单名称绑定。请看下面我的代码：

.html 文件：

<div class="blog-form">
    <form [formGroup]="createBlogForm" (ngSubmit)="createBlog()">
      <div class="form-group form-row">
        <label>Blog Title</label>
        <input type="text" formControlName="blogTitle" class="form-control" placeholder="Enter blog Title"
          required>
      </div>
       <div [hidden]="blogTitle.valid || blogTitle.pristine" class="alert alert-danger">
       Blog Title is required 
      </div> 

      <div class="form-group form-row">
        <label class="col-md-3">Upload Image</label>
        <div class="col-md-9">
          <input type="file" id="imagePath" (change)="onSelectedFile($event)" />
          <div [innerHTML]="uploadError" class="error"></div>
        </div>
      </div>
      <div class="form-group">
        <label>Description</label>
        <input type="text" formControlName="blogDescription" class="form-control" placeholder="Enter Description"
          required>
      </div>

      <div class="form-group">
        <label>Enter the blog body</label>
        <textarea formControlName="blogBodyHtml" class="form-control" rows="3" required></textarea>
      </div>
      <div class="form-group">
        <label>Author</label>
        <input type="text" formControlName="blogAuthor" class="form-control" placeholder="Enter Author name"
          required>
      </div>
      <div class="form-group">
        <label>Category</label>
        <select formControlName="blogCategory" class="form-control" id="category" required>
              <option *ngFor="let category of possibleCategories" [value]="category">{{category}}</option>
            </select>
      </div>


      <button type="submit" class="btn btn-default" [disabled]="!createBlogForm.form.valid">Post the blog</button>

    </form>
  </div>

角组件

public createBlogForm: FormGroup;
  public imagePath: string;

  public blogTitle: string;
  public blogBodyHtml: string;
  public blogDescription: string;
  public blogCategory: string;
  public blogAuthor: string;
  public possibleCategories = ["Comedy", "Action", "Drama", "Technology","Cooking","Travel"];

  constructor(private blogpostService: BlogpostService, private toastr: ToastrManager, private router: Router,
    private _http: HttpClient, private formBuilder: FormBuilder) {

    console.log('CreateBlogComponent component constructor called');
   }
  ngOnInit() {
    console.log("CreateBlogComponent onInIt called");

    this.createBlogForm = this.formBuilder.group({
      blogTitle: [''],
      blogDescription: [''],
      blogBodyHtml: [''],
      blogCategory: [''],
      blogAuthor: [''],
      imagePath:['']
    })

}

onSelectedFile(event) {
  const file = event.target.files[0];
  this.createBlogForm.get('imagePath').setValue(file)
}

public createBlog(): any {
  const formData = new FormData();
  formData.append('imagePath', this.createBlogForm.get('imagePath').value);
  formData.append('title', this.createBlogForm.get('blogTitle').value);
  formData.append('description', this.createBlogForm.get('blogDescription').value);
  formData.append('blogBody', this.createBlogForm.get('blogBodyHtml').value);
  formData.append('category', this.createBlogForm.get('blogCategory').value);
  formData.append('author', this.createBlogForm.get('blogAuthor').value);
 }

  this.blogpostService.createBlog(formData).subscribe(

    data => {

      this.toastr.successToastr('Blog Posted Susseccfully!', 'Success!');


    },

}

标签： angularangular-reactive-formsreactive-forms

angular - 返回错误类型错误的角度反应形式：“_co.blogTitle 未定义”

问题描述

解决方案

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