我正在研究一个todo应用程序来理解反应的力量。我创建了3个组件,我将在下面向您展示。所以我想从位于其他组件中的数组状态中删除待办事项。React通道支持其他组件从状态数组中删除
看看下面我的组件。
这是我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;
在这里,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>
);
}}
出口默认TodoItemComponent
;
class TodoItemComponent extends Component {
deleteTodo(){
// this.setState({
// data: update(this.state.data, {$splice: [[index, 1]]})
// })
console.log('deleteTodo', this.props.todo);
}
render() {
console.log(this.props.todo, this.props.title);
return (
<div>
<li className="list-group-item todo-item">
<button className="btn btn-xs btn-react btn-circle m-r-md">
<span className="fa fa-check"></span>
</button>
{this.props.todo}
<span className="pull-right">
<button className="btn btn-xs btn-react btn-circle m-r-xs">
<span className="fa fa-pencil-square-o"></span>
</button>
<button className="btn btn-xs btn-react btn-circle" onClick={this.deleteTodo}>
<span className="fa fa-trash-o"></span>
</button>
</span>
</li>
</div>
);
}
}
export default TodoItemComponent;
这里是AddTodoComponent:
import TodoItemComponent from '../TodoItemComponent/TodoItemComponent';
class AddTodoComponent extends Component {
constructor(props) {
super(props);
this.state = {
todo: '',
todoArray: []
};
}
addTodo(e){
this.setState({ todo: e.target.value });
this.state.todoArray.push(<TodoItemComponent todo={this.state.todo} onDelete={this.delete}></TodoItemComponent>);
}
delete(index){
// this.setState({
// todoArray: update(this.state.todoArray, {$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;
正如你看到的我尝试删除按钮点击时登录this.props.todo
,所以当它发射出的TodoItemComponent deleteTodo function
。它返回我Uncaught TypeError: Cannot read property 'props' of null
但在render()
方法它被识别并记录输入的结果。
因此我试图在deleteTodo功能道具绑定在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>
因此函数是这样的:
deleteTodo(todo){
console.log('deleteTodo', todo);
this.props.onDelete(this.props.todo);
}
有人能帮助我在这个问题上?
你试过'onDelete = {()=> this.delete(1)}'或其他一些指标? – Li357
你不能在'delete'方法内访问'this.props.todo'的值。所以,你必须为它提供一个上下文,像这样'onClick = {this.delete.bind(this,this.props.todo)}'。有了这个,你可以在'delete'自定义方法中访问待办事项。 – Rowland
您不应该将呈现的React组件存储在状态中。将普通的旧JavaScript对象和数组保存在状态中,并且只在'render'中渲染React组件。 'addTodo'方法会导致渲染的组件被推入到一个在'render'生命周期之外更新的数组中。 –