我如何 hide/display React JS 中的提交按钮

Question

我是 React JS 的新手，我不知道在 ReactJS 中该怎么做。

我一开始必须隐藏提交按钮，当键入日期字段时，应该会显示提交按钮。

class MyForm extends React.Component {
    constructor(props) {
      super(props);
      this.state = { startdate: '', enddate: '' };
    }
    mySubmitHandler = (event) => {
      event.preventDefault();
      alert("You are submitting " + this.state.startdate +"and"+ this.state.enddate);
    }
    myChangeHandler = (event) => {
      this.setState({startdate: event.target.value});
    }

    myEndDate = (event) => {
        this.setState({enddate: event.target.value});
      }

    render() {
      return (
        <form onSubmit={this.mySubmitHandler}>
        <img src="C:\Users\A9002255\Desktop\is.jpg"></img>
        <h2>Please select the Date range of .CSV </h2>
       
        <input
          type='date'
          onChange={this.myChangeHandler}
        />
        <span>   </span>
       <input
          type="date"
          onChange={this.myEndDate}
        />
        <div>
        <input
          type='submit' value="Download" class="bi bi-cloud-arrow-down"  style={{ width: '10%', height: 30}}
        />
        </div>
        </form>
      );
    }
  }
  ReactDOM.render(<MyForm />, document.getElementById('root'));

  export default MyForm;

Answer 1

您可以根据您所在州的开始日期和结束日期添加检查。试试下面的代码

   class MyForm extends React.Component {
constructor(props) {
  super(props);
  this.state = { startdate: '', enddate: '' };
}
mySubmitHandler = (event) => {
  event.preventDefault();
  alert("You are submitting " + this.state.startdate +"and"+ this.state.enddate);
}
myChangeHandler = (event) => {
  this.setState({startdate: event.target.value});
}

myEndDate = (event) => {
    this.setState({enddate: event.target.value});
  }

render() {
  return (
    <form onSubmit={this.mySubmitHandler}>
    <img src="C:\Users\A9002255\Desktop\is.jpg"></img>
    <h2>Please select the Date range of .CSV </h2>
   
    <input
      type='date'
      onChange={this.myChangeHandler}
    />
    <span>   </span>
   <input
      type="date"
      onChange={this.myEndDate}
    />
    <div>
    {this.state.startdate && this.state.enddate && <input
      type='submit' value="Download" class="bi bi-cloud-arrow-down"  style={{ width: '10%', height: 30}}
    />}
    </div>
    </form>
  );
}


}
ReactDOM.render(<MyForm />, document.getElementById('root'));

export default MyForm;

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