Question

说，我有一个组件，它在扩展组件的渲染功能中。

因为只有一个渲染函数会调用，如果我从“面板”中删除该函数，它将在“ ExtendedComponent”上运行，这是它们的其他方式。所以只有通过功能我才能从“ ExtendedComponent”中渲染“ SomeComponent”

class ExtendedComponent extends React.Component {
    constructor(props) {
        super(props);
        this. state = {
            showComponent: false,
        };
    }

    render() {
        console.log(this.state);
        const {showComponent} = this.state;
        return showComponent ? (
           <SomeComponent content="Message sent" />) : null;
    }

    toggleComponent = () => {
        console.log("came here");
        this.setState(({showComponent}) => ({showComponent: !showComponent}));
    };
}

class Panel extends ExtendedComponent {

componentDidMount() {
    this.toggleToast();
}

render() {
    return (
        <div>
            <h1>Hey!!!!!</h1>
        </div>
    );
}
}

Answer 1

有两种方法可以呈现超级组件而不是子组件：

从子组件中删除render方法
明确返回Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database! at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106) at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529) at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128) at org.eclipse.persistence.sessions.JNDIConnector.connect(JNDIConnector.java:123) ... 62 more Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source. at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319) at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557) at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477) at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525) ... 64 more

第二种适用于您的情况，因为它可以动态工作。

super.render();

React Extended Component Render函数调用

1 个答案: