我正在研究一個todo應用程序來理解反應的力量。我創建了3個組件,我將在下面向您展示。所以我想從位於其他組件中的數組狀態中刪除待辦事項。React通道支持其他組件從狀態數組中刪除
看看下面我的組件。
這是我TodoAppComponent:
import AddTodoComponent from '../AddTodoComponent/AddTodoComponent';
class TodoAppComponent extends Component {
render() {
return (
<div id="page-content-wrapper">
<div className="container">
<div className="row">
<div className="col-lg-6 col-lg-offset-3">
<h1 className="m-b-md">What needs to be done?</h1>
<AddTodoComponent></AddTodoComponent>
</div>
</div>
</div>
</div>
);
}
}
export default TodoAppComponent;
在這裏,我有TodoItemComponent:
class TodoItemComponent extends Component {
deleteTodo(todo){
console.log('deleteTodo', todo);
this.props.onDelete(this.props.todo);
}
render() {
console.log('this.props.todo', this.props.todo);
return (
<div>
<li className="list-group-item todo-item">
<button className="btn btn-xs btn-react btn-circle m-r-md">
<span className="fa fa-check"></span>
</button>
{this.props.todo}
<span className="pull-right">
<button className="btn btn-xs btn-react btn-circle m-r-xs">
<span className="fa fa-pencil-square-o"></span>
</button>
<button className="btn btn-xs btn-react btn-circle" onClick={this.deleteTodo.bind(this.props.todo)}>
<span className="fa fa-trash-o"></span>
</button>
</span>
</li>
</div>
);
}}
出口默認TodoItemComponent
;
class TodoItemComponent extends Component {
deleteTodo(){
// this.setState({
// data: update(this.state.data, {$splice: [[index, 1]]})
// })
console.log('deleteTodo', this.props.todo);
}
render() {
console.log(this.props.todo, this.props.title);
return (
<div>
<li className="list-group-item todo-item">
<button className="btn btn-xs btn-react btn-circle m-r-md">
<span className="fa fa-check"></span>
</button>
{this.props.todo}
<span className="pull-right">
<button className="btn btn-xs btn-react btn-circle m-r-xs">
<span className="fa fa-pencil-square-o"></span>
</button>
<button className="btn btn-xs btn-react btn-circle" onClick={this.deleteTodo}>
<span className="fa fa-trash-o"></span>
</button>
</span>
</li>
</div>
);
}
}
export default TodoItemComponent;
這裏是AddTodoComponent:
import TodoItemComponent from '../TodoItemComponent/TodoItemComponent';
class AddTodoComponent extends Component {
constructor(props) {
super(props);
this.state = {
todo: '',
todoArray: []
};
}
addTodo(e){
this.setState({ todo: e.target.value });
this.state.todoArray.push(<TodoItemComponent todo={this.state.todo} onDelete={this.delete}></TodoItemComponent>);
}
delete(index){
// this.setState({
// todoArray: update(this.state.todoArray, {$splice: [[index, 1]]})
// });
console.log('testDelete', this.state.todoArray);
}
handleChange(e){
this.setState({ todo: e.target.value });
}
render() {
return (
<div>
<div className="input-group m-b-md">
<input type="text" className="form-control add-todo" placeholder="Todo..." value={this.state.todo} onChange={this.handleChange.bind(this)} />
<span className="input-group-btn">
<button className="btn btn-react" type="button" onClick={this.addTodo.bind(this)}>Add</button>
</span>
</div>
<ul className="list-group">
{this.state.todoArray}
</ul>
</div>
);
}
}
export default AddTodoComponent;
正如你看到的我嘗試刪除按鈕點擊時登錄this.props.todo
,所以當它發射出的TodoItemComponent deleteTodo function
。它返回我Uncaught TypeError: Cannot read property 'props' of null
但在render()
方法它被識別並記錄輸入的結果。
因此我試圖在deleteTodo功能道具綁定在TodoItemComponent
:
<button className="btn btn-xs btn-react btn-circle" onClick={this.deleteTodo.bind(this.props.todo)}>
<span className="fa fa-trash-o"></span>
</button>
因此函數是這樣的:
deleteTodo(todo){
console.log('deleteTodo', todo);
this.props.onDelete(this.props.todo);
}
有人能幫助我在這個問題上?
你試過'onDelete = {()=> this.delete(1)}'或其他一些指標? – Li357
你不能在'delete'方法內訪問'this.props.todo'的值。所以,你必須爲它提供一個上下文,像這樣'onClick = {this.delete.bind(this,this.props.todo)}'。有了這個,你可以在'delete'自定義方法中訪問待辦事項。 – Rowland
您不應該將呈現的React組件存儲在狀態中。將普通的舊JavaScript對象和數組保存在狀態中,並且只在'render'中渲染React組件。 'addTodo'方法會導致渲染的組件被推入到一個在'render'生命週期之外更新的數組中。 –