HarmonyOS Eventhub 注册的响应函数无法访问所在类中的其它属性字段

this.context.eventHub.on('myEvent', ()=>{this.eventFunc1()})

url: string = "123456" 
eventFunc1() { 
  console.info("testTag-" + this.url) 
} 
private callback = ()=>{this.eventFunc1()}; 
onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void { 
  this.context.eventHub.on('myEvent', this.callback) 
  this.context.eventHub.off("myEvent", this.callback) 
  hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onCreate'); 
}