angular2模板驱动表单验证问题

Question

我有angular2模板驱动表单验证的问题，以下是我的表单的代码。

  <h1>{{page_title}}</h1>
  <div *ngIf="success_flag" class="alert alert-success">
        {{success_message.message}}
  </div>
  <form  #add_book_form="ngForm"  (ngSubmit)="add_book(add_book_form)" novalidate>
              <div class="row">
                          <div class="col-sm-12 col-md-12 col-lg-12 col-xs-12">
                                      <div class="form-group clearfix">
                                            <label>Book Name</label>
                                            <input name="book_name" id="book_name" [(ngModel)]="book_name" class="form-control" required>
                                            <div *ngIf="book_name.invalid && (book_name.dirty || book_name.touched)" class="alert alert-danger">
                                                              <div *ngIf="book_name.errors.required">
                                                              Book Name is required.
                                                              </div>


                                                              </div>
                                      </div>
                                </div>
              </div>
              <div class="row">
                          <div class="col-sm-12 col-md-12 col-lg-12 col-xs-12">
                                      <div class="form-group clearfix">
                                            <label>Book Description</label>
                                            <textarea name="book_description" [(ngModel)]="book_description" class="form-control" required></textarea>
                                      </div>
                                </div>
              </div>
              <div class="row">
                          <div class="col-sm-12 col-md-12 col-lg-12 col-xs-12">
                                      <div class="form-group clearfix">
                                            <label>Book Published Date</label>
                                            <input name="book_published_date" [(ngModel)]="book_published_date" class="form-control"  required>
                                      </div>
                                </div>
              </div>      
              <div class="row">
                          <div class="col-sm-12 col-md-12 col-lg-12 col-xs-12">
                                      <div class="form-group clearfix">
                                            <label>Cover Image</label>
                                            <input name="book_cover_image" [(ngModel)]="book_cover_image" class="form-control" type="file" (change)="getFiles($event,'cover_image')" required>
                                      </div>
                                </div>
              </div>
              <div class="row">
                          <div class="col-sm-12 col-md-12 col-lg-12 col-xs-12">
                                      <div class="form-group clearfix">
                                            <label>PDF Copy</label>
                                            <input name="book_pdf_copy" [(ngModel)]="book_pdf_copy" class="form-control" type="file" (change)="getFiles($event,'pdf_copy')" required>
                                      </div>
                                </div>
              </div>
              <div class="row">
                          <div class="col-sm-12 col-md-12 col-lg-12 col-xs-12">
                                      <div class="form-group clearfix">
                                            <label>PDF Sample</label>
                                            <input name="book_pdf_sample" [(ngModel)]="book_pdf_sample" class="form-control" type="file" (change)="getFiles($event,'pdf_sample')" required>
                                      </div>
                                </div>
              </div>
              <div class="row">
                          <div class="col-sm-12 col-md-12 col-lg-12 col-xs-12">
                                      <div class="form-group clearfix">
                                            <label>Price</label>
                                            <input name="book_price" [(ngModel)]="book_price" class="form-control" type="number" required>
                                      </div>
                                </div>
              </div>
              <div class="row">
                          <div class="col-sm-12 col-md-12 col-lg-12 col-xs-12">
                                      <div class="form-group clearfix  text-center">
                                            <button [disabled]="add_book_form.invalid" class="btn btn-success">Save Book</button>
                                      </div>
                                </div>
              </div>      
        </form>

目前正在禁用提交按钮。当我尝试填写书名字段时，必须启用它，但它仍然不起作用，我不知道究竟存在哪个问题。错误消息也没有显示相同。

请帮忙。谢谢

Answer 1

@DBQ是对的。

而不是使用：

<button [disabled]="add_book_form.invalid" class="btn btn-success">Save Book</button>

你应该使用：

<button [disabled]="add_book_form.controls['book_name'].invalid" class="btn btn-success">Save Book</button>