从非异步方法调用异步方法

Question

void Entry_TextChanged(object sender, TextChangedEventArgs e)
{
     var newText = e.NewTextValue;
     //once 3 keystroke is visible by 3
     if (newText.Length % 3 == 0)
     {
          //Call the web services
          var result = GettingModel(newText);
          if (result != null || result != string.Empty)
          {
               ModelVIN.Text = result;
          }    
     }
}

private string GettingModel(string vinText)
{
      var task = getModelForVIN(vinText);
      var result = task.Result;    
      return result.Model;
}

private async Task<VINLookUp> getModelForVIN(string vinText)
{
      var deviceId = CrossDeviceInfo.Current.Model;
      deviceId = deviceId.Replace(" ", "");
      var requestMgr = new RequestManager(deviceId);

      var VinData = new VINLookUp();    
      VinData = await requestMgr.getModelForVIN(vinText);    
      return VinData;
}

Answer 1

您不需要gettingmodel(string vinText)方法。通过调用task.result，您将阻塞主线程。

在UI线程中调用.result可能会死锁您正在经历的一切。使用continuewith或async voidwithawait。

您可以使entry_textchanged异步和awaitweb请求，这样它就不会阻塞UI。

private async void Entry_TextChanged(object sender, TextChangedEventArgs e)
{
     var newText = e.NewTextValue;
     //once 3 keystroke is visible by 3
     if (newText.Length % 3 == 0)
     {
          //Call the web services
          var result = await GetModelStringForVIN(newText);
          if (string.IsNullOrEmpty(result) == false)
          {
               ModelVIN.Text = result;
          }    
     }
} 

private async Task<string> GetModelStringForVIN(string vinText)
{
      var deviceId = CrossDeviceInfo.Current.Model;
      deviceId = deviceId.Replace(" ", string.Empty);
      var requestMgr = new RequestManager(deviceId);

      var VinData = await requestMgr.getModelForVIN(vinText);

      return VinData?.Model;
 }

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