反应-左击未触发onMouseDown/onMouseUp

Question

我正在使用react组件中HTML画布上的鼠标事件，但在鼠标左键单击未触发onMouseDown/onMouseUp时有一个问题。它适用于右击和中心单击。

handleMouseDown(event)
{
    console.log("mouse down");
}

handleMouseMove(event)
{
    console.log("mouse move");
}

handleMouseUp(event)
{
    console.log("mouse up");
}

render() {
    return (
        <div
            className="chart">
            <canvas
                id="canvas"
                onMouseDown={this.handleMouseDown}
                onMouseMove={this.handleMouseMove.bind(this)}
                onMouseUp={this.handleMouseUp.bind(this)} />
        </div>
    );

以前有人经历过吗？

编辑注释:我正在尝试获取鼠标向下事件发生的位置的X/Y坐标。

Answer 1

您可以在左键单击时使用onClick：

​

class MyComponent extends React.Component {

  constructor(props) {
    super(props);
    this.handleClick = this.handleClick.bind(this);
  }

  handleClick(event){
    const yCoord = event.y;
    const xCoord = event.x;
    console.log("Y Coordinate = " + yCoord + 
    "\n X Coordinate = " + xCoord + ".");
    
    switch(event.which) {
      case 1: {
        console.log('Left Mouse button pressed.');
        break;
      }
      case 2: {
        console.log('Middle Mouse button pressed.');
        break;
      }
      case 3: {
        console.log('Right Mouse button pressed.');
        break;
      }
      default: {
        console.log('You have a strange Mouse!');
      }
    }
  }
  
  render() {
    return (
      <div className="chart">
        <canvas id="canvas" 
          onClick={(e) =>{this.handleClick(e.nativeEvent)}}
          onContextMenu={(e) =>
            {this.handleClick(e.nativeEvent)}}>
        </canvas>
      </div>
    );
  }
}

ReactDOM.render(
  <MyComponent />,
  document.getElementById('container')
);

.chart {
  width: 100;
  height: 100;
}

#canvas {
  border: 1px black solid;
  width: 50;
  height: 50;
  background-color: blue;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="container">
  <!-- This element's contents will be replaced with your component. -->
</div>

​

Answer 2

事件处理程序也可能是箭头函数。有关更多信息，请查看React文档处理事件。