HttpClient.PostAsync 崩溃应用。 如何捕捉异常？

Question

I'm trying to test this HttpRequest:

 public void TestX(string baseUrl)
        {
            StringContent httpContentDistanza = new StringContent(GlobalVariables.JsonDistanza);
            using HttpClient httpClient = new HttpClient
            {
                BaseAddress = new Uri(baseUrl)
            };

            HttpResponseMessage responseMessage = null;

            try
            {
                responseMessage = httpClient.PostAsync("/xxx/xx/xxx", httpContentDistanza).Result;
              // can't reach the code below
                if (responseMessage.IsSuccessStatusCode)
                {
                    string strContext = responseMessage.Content.ReadAsStringAsync().Result;

                    var risultato = JsonSerializer.Deserialize<Distanza1>(strContext);

                    GlobalVariables.DblAijCrnPsz = risultato.data.processDataIn.valore;
                }
            }
            catch (Exception ex)
            {
                if (responseMessage == null)
                {
                    responseMessage = new HttpResponseMessage();
                }
                responseMessage.StatusCode = HttpStatusCode.InternalServerError;
                responseMessage.ReasonPhrase = string.Format("RestHttpClient.SendRequest failed: {0}", ex);
            
            }
        }

The problem is that the URI is not reachable, and I was expecting that its gonna throw some Exception, but it did not.

In case where URI is not reachable I need some how to catch that Exception.

I'm using BackgroundWorker to run TestX() :

public MainWindow()
        {
            InitializeComponent();
            bgWorker = new BackgroundWorker { WorkerReportsProgress = true };
            bgWorker.DoWork += ResetAll;

        }

        private void ResetAll(object sender, DoWorkEventArgs e)
        {
           var x = gestLink.TestX(GlobalVariables.BaseUrl).ToString();
           //it also does't reach the code below

               ....
        }

---

Update

I don't know what I'm doing wrong.. I still can't catch the exception:

     public async Task TestX(string baseUrl)
            {
              StringContent httpContentDistanza = new  StringContent(GlobalVariables.JsonDistanza);

              using HttpClient httpClient = new HttpClient
               {
                  BaseAddress = new Uri(baseUrl)
               };
        
               HttpResponseMessage responseMessage = null;
             
                try
                {
                    responseMessage = await client.PostAsync("/xxx/xxx/xx", httpContentDistanza);
    
                    if (responseMessage.IsSuccessStatusCode)
                    {
                        string strContext = await responseMessage.Content.ReadAsStringAsync();
    
                     var risultato = JsonSerializer.Deserialize<Distanza1>(strContext);

                    }
                }
                catch(Exception ex)
                {
                    var error = ex.Message;
                }

It crash here responseMessage = await httpClient.PostAsync("/xxx/xx/xxx", httpContentDistanza); but stops in ResetAll() and var x = this .

---

I have seen and read similar problems ( Debugger stops after async HttpClient.GetAsync() and HttpClient.PostAsync and await crashing app ) before, but no solutions have helped me. Any suggestions how to catch the exception?

Answer 1

You should change this:

public void TestX(string baseUrl) 

to

public async Task TestX(string baseUrl)

and this

responseMessage = httpClient.PostAsync("/xxx/xx/xxx",httpContentDistanza).Result;

to

responseMessage = await httpClient.PostAsync("/xxx/xx/xxx", httpContentDistanza);

Then you can handle Exceptions.