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How can i manage exceptions from Client.PostAsync<T>? [duplicate]

I was hoping somebody could enlighten me a little bit on an issue I am facing in regards to async/await exception handling with HttpClient. I have written some code to illustrate, and it is being excecuted on both a Windows Phone 8 device and the emulator:
private async void SearchButton_Click(object sender, EventArgs e)
{
try
{
HttpClient client = new HttpClient();
System.Diagnostics.Debug.WriteLine("BEGIN FAULTY REQUEST:");
string response = await client.GetStringAsync("http://www.ajshdgasjhdgajdhgasjhdgasjdhgasjdhgas.tk/");
System.Diagnostics.Debug.WriteLine("SUCCESS:");
System.Diagnostics.Debug.WriteLine(response);
}
catch (Exception exception)
{
System.Diagnostics.Debug.WriteLine("CAUGHT EXCEPTION:");
System.Diagnostics.Debug.WriteLine(exception);
}
}
Tapping the button that invokes this function, produces the following output in the debugger console, the most interesting being the ones in bold:
BEGIN FAULTY REQUEST:
An exception of type 'System.Net.WebException' occurred in System.Windows.ni.dll and wasn't handled before a managed/native boundary
An exception of type 'System.Net.WebException' occurred in System.Windows.ni.dll and wasn't handled before a managed/native boundary
A first chance exception of type 'System.Net.Http.HttpRequestException' occurred in mscorlib.ni.dll
An exception of type 'System.Net.Http.HttpRequestException' occurred in mscorlib.ni.dll and wasn't handled before a managed/native boundary
CAUGHT EXCEPTION:
(and here it prints out the HttpRequestException)
Of course I am expecting an error in this case since the URL I am calling is nonsense. What I am not understanding here, is why the debugger reports that the exceptions are not handled, when the output simultaneously reports that the exception is caught. Also, the UI side of the app becomes much less responsive while the output is being printed, indicating that something is probably amiss.
Is this not the way to handle exceptions when working with async and await? I appreciate any input! Thanks.

As you are using HttpClient, try to use response.EnsureSuccessStatusCode();
Now HttpClient will throw exception when response status is not a success code.
try
{
HttpResponseMessage response = await client.GetAsync("http://www.ajshdgasjhdgajdhgasjhdgasjdhgasjdhgas.tk/");
response.EnsureSuccessStatusCode(); // Throw if not a success code.
// ...
}
catch (HttpRequestException e)
{
// Handle exception.
}
ORIGINAL SOURCE OF THE CODE: http://www.asp.net/web-api/overview/advanced/calling-a-web-api-from-a-net-client

This is an artifact of the debugger. It's determining that an exception is "uncaught" because it's not caught yet. In this case this is expected behavior.
You are handling the exceptions correctly.

The debugger is telling you that this exception is first chance. When a debugger is attached to your process it gets notified for every exception that is thrown and then based on how the debugger has been configured it will decide what to do with it. You can go through What is first chance exception? for more details.
On a side note, catch specific exceptions only so that you understand which exceptions you are expecting and why.

Helix toolkit WPF CameraController Rotation Mode crash

control.viewPort.CameraController.CameraRotationMode = CameraRotationMode.Turnball;
Throws helpful error
"An exception of type 'System.NullReferenceException' occurred in
your.exe but was not handled in user code"
RotateGesture works, also adding children, but not changes in RotationMode - why?

WinRT ObservableCollection.RemoveAt() results in COMExcetion HRESULT E_FAIL

I have an ObservableCollection that a ListBox is databound to. I can add items to the ObservableCollection without issue, and the UI updates, but if I try to call either Remove or RemoveAt to allow the user to delete entries I end up with this:
'10Done.WindowsPhone.exe' (CoreCLR: .): Loaded
'C:\windows\system32\en-US\mscorlib.debug.resources.dll'. Module was
built without symbols. A first chance exception of type
'System.Runtime.InteropServices.COMException' occurred in
mscorlib.ni.dll An exception of type
'System.Runtime.InteropServices.COMException' occurred in
mscorlib.ni.dll but was not handled in user code Additional
information: Error HRESULT E_FAIL has been returned from a call to a
COM component.
Can I not remove items from a collection that is databound?

I have a error in make a new MainWindow in wpf

I have a error in my wpf project. When I want make a new from MainWindow in The following code:
public App()
{
System.Windows.Forms.Application.EnableVisualStyles();
System.Windows.Forms.Application.SetCompatibleTextRenderingDefault(false);
if (MyServer.IsAdministrator())
{
if (MyServer.IsRun())
Process.GetCurrentProcess().Kill();
else
{
MainWindow ObjMain = new MainWindow();
ObjMain.Show();
}
}
else
{
new CheckRunAsAdministrator().ShowDialog();
Process.GetCurrentProcess().Kill();
}
}
I see:
An unhandled exception of type 'System.InvalidOperationException' occurred in PresentationCore.dll
Additional information: The calling thread must be STA, because many UI components require this.
But after this error I remove codes in App() and in App.xaml wrote
But I see another problem. Please see the below.
A first chance exception of type 'System.NotImplementedException'
occurred in PresentationFramework.dll
Additional information: The method or operation is not implemented.
and after that:
An unhandled exception of type
'System.Windows.Markup.XamlParseException' occurred in
PresentationFramework.dll
Additional information: The method or operation is not implemented.
what's the problem?

How to fix "'System.AggregateException' occurred in mscorlib.dll"

I'm receiving an unhandled exception while debugging, and the program stops executing. The debugger doesn't show me the line so I don't know what to fix.
An unhandled exception of type 'System.AggregateException' occurred in mscorlib.dll
Additional information: A Task's exception(s) were not observed either by Waiting on the Task or accessing its Exception property. As a result, the unobserved exception was rethrown by the finalizer thread.
Cannot obtain value of local or argument '<this>' as it is not available at this instruction pointer, possibly because it has been optimized away. System.Threading.Tasks.TaskExceptionHolder
How can I troubleshoot this problem?
I also found this question which is pretty similar.

As the message says, you have a task which threw an unhandled exception.
Turn on Break on All Exceptions (Debug, Exceptions) and rerun the program.
This will show you the original exception when it was thrown in the first place.
(comment appended): In VS2015 (or above). Select Debug > Options > Debugging > General and unselect the "Enable Just My Code" option.

You could handle the exception directly so it would not crash your program (catching the AggregateException). You could also look at the Inner Exception, this will give you a more detailed explanation of what went wrong:
try {
// your code
} catch (AggregateException e) {
}

The accepted answer will work if you can easily reproduce the issue. However, as a matter of best practice, you should be catching any exceptions (and logging) that are executed within a task. Otherwise, your application will crash if anything unexpected occurs within the task.
Task.Factory.StartNew(x=>
throw new Exception("I didn't account for this");
)
However, if we do this, at least the application does not crash.
Task.Factory.StartNew(x=>
try {
throw new Exception("I didn't account for this");
}
catch(Exception ex) {
//Log ex
}
)

In my case I ran on this problem while using Edge.js — all the problem was a JavaScript syntax error inside a C# Edge.js function definition.