響應式表單> 利用FormArray建立表單陣列

src/app/app.component.html

@@ -1,9 +1,9 @@
 <div [formGroup] = "form">
-  <div>帳號：<input type="text" formControlName="id" /></div>
-  <div>密碼：<input type="password" formControlName="password" /></div>
-  <div>
-    <button type="reset">重設</button>
-    <button type="submit">登入</button>
+  <div formArrayName="Tasks" *ngFor="let control of tasks.controls; let index = index">
+    <ng-container [formGroupName]="index">
+      <input type="text" placeholder="主旨" formControlName="Subject"/>
+      <input type="text" placeholder="內容" formControlName="Content"/>
+    </ng-container>
   </div>
 </div>
 <pre>{{form.value| json}}</pre>

src/app/app.component.ts

@@ -1,5 +1,5 @@
 import { Component } from '@angular/core';
-import { FormControl, FormGroup } from '@angular/forms';
+import { FormArray, FormControl, FormGroup } from '@angular/forms';
 
 
 @Component({
@@ -9,8 +9,20 @@ import { FormControl, FormGroup } from '@angular/forms';
 })
 export class AppComponent  {
   readonly form = new FormGroup({
-    id:new FormControl(),
-    password: new FormControl(),
+    Tasks: new FormArray([]),
   });
 
+  get tasks(): FormArray{
+    return this.form.get('Tasks') as FormArray;
+  }
+
+  ngOnInit(): void{
+    this.tasks.push(//注意此push用法
+      new FormGroup({
+        Subject: new FormControl(),
+        Content: new FormControl(),
+      })
+    );
+  }
+
 }