Exception while debugging

Question

I created a view who have two entry and a button with a command to consume a rest api in my physical device but i got this exception while debugging:

[System.out] [OkHttp] sendRequest<< [apitrace] apitrace: warning: caught signal 11 [apitrace] call flush from exceptionCallback [libc] Fatal signal 11 (SIGSEGV), code 2 (SEGV_ACCERR), fault addr 0x7ffaf31ff0 in tid 15432 (companyname.add), pid 15432 (companyname.add)

this is the view:


    <ContentPage.Content>
        <StackLayout>
            <Entry Text="{Binding Machine_Qr}"></Entry>
            <Entry Text="{Binding Machine_Name}"></Entry>
            <Button Text="add the machine" Command="{Binding Ajout}"></Button>
        </StackLayout>
    </ContentPage.Content>

this is the View Model:

 public class AjoutMachineVM : BaseViewModel
    {
        public string machine_Name;
        public string machine_Qr;
        IMachineService _rest = DependencyService.Get<IMachineService>();



        public AjoutMachineVM()
        { 
            SaveMachine();
        }

        public async Task SaveMachine()
        {
            try
            {
                var machine = new Machine
                {
                    Machine_Name = machine_Name,
                    Machine_Qr = machine_Qr

                };

                await _rest.AddMachine(machine);

                await Shell.Current.GoToAsync("..");
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }
        public string Machine_Qr
        {
            get => Machine_Qr;
            set
            {
                machine_Qr = value;
                NotifyPropertyChanged(nameof(Machine_Qr));
            }
        }
        public string Machine_Name
        {
            get => Machine_Name;
            set
            {
                machine_Name = value;
                NotifyPropertyChanged(nameof(Machine_Name));
            }
        }
        public ICommand Ajout { get; }

    }

and this is the service :

public class MachineService : IMachineService
    {
        public  string Base_url = "http://192.168.1.112:45455/api/";

       public async Task AddMachine(Machine machine)
        {
            string url = Base_url + "machine/creation";

            HttpClient client = new HttpClient();

            var response = await client.PostAsync(url,
                           new StringContent(JsonConvert.SerializeObject(machine), Encoding.UTF8, "application/json"));

        }
    }

the exception comes after exectuting this line in the MachineService class :

 var response = await client.PostAsync(url,
                               new StringContent(JsonConvert.SerializeObject(machine), Encoding.UTF8, "application/json"));

There is no line mentioned but the exception is in the view model — Gazdallah Amira, Jun 03 '22 at 15:02
did you look at the stack trace? Or step through the code in the debugger? Is this an exception being caught by one or your try/catch blocks, or an unhandled exception? — Jason, Jun 03 '22 at 15:05
then you need to step through the code until you find the line that triggers it — Jason, Jun 03 '22 at 15:09
This comes up in every question you post. You need to learn to use the debugger. Or add some basic console logging to your app so you can determine which lines execute before the crash. — Jason, Jun 03 '22 at 15:14
I'm confused because I'm new in xamarin and this is a final project — Gazdallah Amira, Jun 03 '22 at 15:20
You'll have to find the line that crashes. Things to try 1) Put try..catch around more code. 2) Put breakpoint at start of each method. Continue until it crashes. Thus the problem is in the last method you were in. Start again, with only that one breakpoint. This time, step through lines of that method. 3) Comment out most of the code (so that it does not crash). Start adding the code back gradually, until it crashes. — ToolmakerSteve, Jun 03 '22 at 18:25
@ToolmakerSteve thank you that helped me, the break point was stopped in the SaveMachine method in the ViewModel class — Gazdallah Amira, Jun 03 '22 at 19:27
Use F10 (Debug / Step Over) to run lines one at a time, until you find the exact line that crashes. — ToolmakerSteve, Jun 03 '22 at 19:35
the exception line is : response.EnsureSuccessStatusCode(); – — Gazdallah Amira, Jun 03 '22 at 22:12
This mean the httprequest is failed, you can check this [link](https://stackoverflow.com/questions/21097730/usage-of-ensuresuccessstatuscode-and-handling-of-httprequestexception-it-throws). — Liyun Zhang - MSFT, Jun 08 '22 at 03:00

Exception while debugging

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