HarmonyOS 如何在应用启动时，获取当应用的版本相关信息，并使用首选项进行持久化？

import { BusinessError } from '@kit.BasicServicesKit'; 
import bundleManager from '@ohos.bundle.bundleManager'; 
import dataPreferences from '@ohos.data.preferences'; 
 
let preferences: dataPreferences.Preferences | null = null; 
 
export default class EntryAbility extends UIAbility { 
 
  ...... 
 
  onWindowStageCreate(windowStage: window.WindowStage): void { 
 
    let options: dataPreferences.Options = { name: 'myStore' }; 
    try{ 
      preferences = dataPreferences.getPreferencesSync(this.context, options); 
    }catch (err){ 
      console.error("Failed to get preferences. code =" + err.code + ", message =" + err.message); 
    } 
 
    let bundleFlags = bundleManager.BundleFlag.GET_BUNDLE_INFO_DEFAULT; 
    try { 
      bundleManager.getBundleInfoForSelf(bundleFlags).then((data) => { 
 
        hilog.info(0x0000, 'testTag', 'getBundleInfoForSelf successfully. Data: %{public}s', JSON.stringify(data)); 
        if(preferences){ 
          preferences.putSync('versionName', data.versionName); 
        } 
      }).catch((err: BusinessError) => { 
        hilog.error(0x0000, 'testTag', 'getBundleInfoForSelf failed. Cause: %{public}s', err.message); 
      }); 
    } catch (err) { 
      let message = (err as BusinessError).message; 
      hilog.error(0x0000, 'testTag', 'getBundleInfoForSelf failed: %{public}s', message); 
    } 
 
    windowStage.loadContent('pages/Index', (err, data) => { 
      ...... 
    }); 
  } 
  ...... 
}