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How to use Clipboard.Default.SetTextAsync in MAUI with FileSystemWatcher

I have followed https://learn.microsoft.com/en-us/dotnet/maui/platform-integration/data/clipboard?view=net-maui-7.0 in my project, and I understand that:
Access to the clipboard must be done on the main user interface thread. For more information on how to invoke methods on the main user interface thread, see MainThread.
I cannot do Clipboard.Default.SetTextAsync(url) without errors, and I can't understand where I've done wrong.
The URL is generated through the OnCreated() method of FileSystemWatcher.
I understand this is not the UI thread, but I fire an event which I believe should enable UI thread operations
I would like to get this code below fixed so that I can my app in macOS without any issues.
You can also check the code in GitHub by pulling the following two projects:
https://github.com/McoreD/UploaderX/tree/maui
https://github.com/McoreD/HelpersLib.git
My code is as below.
using HelpersLib;
using Microsoft.Extensions.Logging;
using ShareX.HelpersLib;
using ShareX.UploadersLib;
namespace UploaderX;
public partial class MainPage : ContentPage
{
int count = 0;
private FileSystemWatcher _watcher;
private string _watchDir;
private string _destDir;
public delegate void UrlReceivedEventHandler(string url);
public event UrlReceivedEventHandler UrlReceived;
public MainPage()
{
InitializeComponent();
string AppDir = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments), "UploaderX");
string AppSettingsDir = Path.Combine(AppDir, "Settings");
App.Settings = ApplicationConfig.Load(Path.Combine(AppSettingsDir, "ApplicationConfig.json"));
App.UploadersConfig = UploadersConfig.Load(Path.Combine(AppSettingsDir, "UploadersConfig.json"));
App.UploadersConfig.SupportDPAPIEncryption = false;
DebugHelper.Init(Path.Combine(AppDir, $"UploaderX-{DateTime.Now.ToString("yyyyMMdd")}-Log.txt"));
_watchDir = Directory.Exists(App.Settings.CustomScreenshotsPath2) ? App.Settings.CustomScreenshotsPath2 : Path.Combine(AppDir, "Watch Folder");
Helpers.CreateDirectoryFromDirectoryPath(_watchDir);
_destDir = _watchDir;
DebugHelper.Logger.WriteLine("Watch Dir: " + _watchDir);
DebugHelper.Logger.WriteLine("Destination Dir: " + _destDir);
_watcher = new FileSystemWatcher();
_watcher.Path = _watchDir;
_watcher.NotifyFilter = NotifyFilters.FileName;
_watcher.Created += OnCreated;
_watcher.EnableRaisingEvents = true;
this.UrlReceived += MainPage_UrlReceived;
}
private async void MainPage_UrlReceived(string url)
{
await Clipboard.Default.SetTextAsync(url);
}
private void OnUrlReceived(string url)
{
UrlReceived?.Invoke(url);
}
private async void OnCounterClicked(object sender, EventArgs e)
{
count++;
if (count == 1)
CounterBtn.Text = $"Clicked {count} time";
else
CounterBtn.Text = $"Clicked {count} times";
await Clipboard.Default.SetTextAsync(CounterBtn.Text);
}
async void OnCreated(object sender, FileSystemEventArgs e)
{
try
{
string fileName = new NameParser(NameParserType.FileName).Parse("%y%mo%d_%ra{10}") + Path.GetExtension(e.FullPath);
string destPath = Path.Combine(Path.Combine(Path.Combine(_destDir, DateTime.Now.ToString("yyyy")), DateTime.Now.ToString("yyyy-MM")), fileName);
FileHelpers.CreateDirectoryFromFilePath(destPath);
if (!Path.GetFileName(e.FullPath).StartsWith("."))
{
int successCount = 0;
long previousSize = -1;
await Helpers.WaitWhileAsync(() =>
{
if (!FileHelpers.IsFileLocked(e.FullPath))
{
long currentSize = FileHelpers.GetFileSize(e.FullPath);
if (currentSize > 0 && currentSize == previousSize)
{
successCount++;
}
previousSize = currentSize;
return successCount < 4;
}
previousSize = -1;
return true;
}, 250, 5000, () =>
{
File.Move(e.FullPath, destPath, overwrite: true);
}, 1000);
WorkerTask task = new WorkerTask(destPath);
UploadResult result = task.UploadFile();
DebugHelper.Logger.WriteLine(result.URL);
OnUrlReceived(result.URL);
}
}
catch (Exception ex)
{
DebugHelper.Logger.WriteLine(ex.Message);
}
}
}
Error once URL is generated:

You can wrap your call to SetTextAsync() with MainThread.BeginInvokeOnMainThread() like so to make sure it's invoked correctly:
private void MainPage_UrlReceived(string url)
{
MainThread.BeginInvokeOnMainThread(() =>
{
Clipboard.Default.SetTextAsync(url);
});
}
There is no need to await the call to SetTextAsync(), either, because you're calling it as a singular operation from within an event handler, which isn't awaitable.
I understand this is not the UI thread, but I fire an event which I believe should enable UI thread operations
Generally, there is no guarantee that event handlers of UI classes are called on the Main Thread.
You can find more information on when and how to invoke methods on the Main Thread in the official documentation: https://learn.microsoft.com/en-us/dotnet/maui/platform-integration/appmodel/main-thread?view=net-maui-7.0

C# Receiving console writeline in richtextbox from windows forms

I have looked at all similar questions. I cant seem to figure out why my situation does not work. I created a test app using the following class:
public class TextBoxStreamWriter : TextWriter
{
RichTextBox _output = null;
public TextBoxStreamWriter(RichTextBox output)
{
_output = output;
}
public override void Write(char value)
{
base.Write(value);
_output.AppendText(value.ToString()); // When character data is written, append it to the text box.
}
public override Encoding Encoding
{
get { return System.Text.Encoding.UTF8; }
}}
My Form Code
public partial class Form1 : Form
{
TextWriter _writer = null;
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
_writer = new TextBoxStreamWriter(richTextBox1);
// Redirect the out Console stream
Console.SetOut(_writer);
//Console.WriteLine("Now redirecting output to the text box");
}
private void button1_Click(object sender, EventArgs e)
{
// Writing to the Console now causes the text to be displayed in the text box.
Console.WriteLine("Hello world");
}
}
This works every time I click the button. Now the reason for my question is why does it work there and not in my project. I created a Youtube uploader app using API 3 it uploads completes but the console writeline show the messages but my richtextbox only shows my intial Video uploading message. Altimately I only want to capture the write for a couple of reasons Show any errors, Get progress to for progressbar and get video.ID when I call Console.writeline my richtextbox does not get updated heres the code being used
/// <summary>
/// Upload video to youtube
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button2_Click(object sender, EventArgs e)
{
//lblstatus.Text = "uploading video";
Console.WriteLine("uploading video");
try
{
Thread thead = new Thread(() =>
{
Run().Wait();
});
thead.IsBackground = true;
thead.Start();
}
catch (AggregateException ex)
{
Console.WriteLine("Error: " + ex.Message);
// MessageBox.Show(ex.Message);
}
}
private async Task Run()
{
UserCredential credential;
using (var stream = new FileStream("client_secret", FileMode.Open, FileAccess.Read))
{
credential = await GoogleWebAuthorizationBroker.AuthorizeAsync(
GoogleClientSecrets.FromStream(stream).Secrets,
// This OAuth 2.0 access scope allows an application to upload files to the
// authenticated user's YouTube channel, but doesn't allow other types of access.
new[] { YouTubeService.Scope.YoutubeUpload },
"user",
CancellationToken.None
);
}
var youtubeService = new YouTubeService(new BaseClientService.Initializer()
{
HttpClientInitializer = credential,
ApplicationName = Assembly.GetExecutingAssembly().GetName().Name
});
var video = new Video();
video.Snippet = new VideoSnippet();
video.Snippet.Title = txtTitle.Text;
video.Snippet.Description = txtDescription.Text;
string[] tagSeo = Regex.Split(txtTagSeo.Text, ",");
video.Snippet.Tags = tagSeo;
video.Snippet.CategoryId = "22"; // See https://developers.google.com/youtube/v3/docs/videoCategories/list
video.Status = new VideoStatus();
video.Status.PrivacyStatus = "public"; // or "private" or "public"
var filePath = txtPath.Text; // Replace with path to actual movie file.
Console.WriteLine(filePath);
using (var fileStream = new FileStream(filePath, FileMode.Open))
{
var videosInsertRequest = youtubeService.Videos.Insert(video, "snippet,status", fileStream, "video/*");
videosInsertRequest.ProgressChanged += videosInsertRequest_ProgressChanged;
videosInsertRequest.ResponseReceived += videosInsertRequest_ResponseReceived;
await videosInsertRequest.UploadAsync();
}
}
void videosInsertRequest_ProgressChanged(Google.Apis.Upload.IUploadProgress progress)
{
switch (progress.Status)
{
case UploadStatus.Uploading:
Console.WriteLine("{0} bytes sent.", progress.BytesSent);
//lblstatus.Text = String.Format("{0} bytes sent.", progress.BytesSent);
break;
case UploadStatus.Failed:
//lblstatus.Text = String.Format("An error prevented the upload from completing.{0} ", progress.Exception);
Console.WriteLine("An error prevented the upload from completing.\n{0}", progress.Exception);
break;
}
}
void videosInsertRequest_ResponseReceived(Video video)
{
Console.WriteLine("Video id '{0}' was successfully uploaded.", video.Id);
MessageBox.Show("Video id '{0}' was successfully uploaded.", video.Id);
}

I was unable to make the above code work so I went to plan B. I started with getting the Video ID only because I only get 6 tries per day I choose to use the Video ID as string. I eliminated the TextBoxStreamWriter class all together and went with creating a new thread and delegate. I will work on the progressbar value next. here's how I did it for anyone else who may have a similar problem.
Created a delegate to update my video ID Label as follows
public delegate void LabelDelegate(string s);
void UpdateVideoID(string text)
{
if (lblVideoID.InvokeRequired)
{
LabelDelegate LDEL = new LabelDelegate(UpdateVideoID);
lblVideoID.Invoke(LDEL, text);
}
else
lblVideoID.Text = text;
}
void videosInsertRequest_ResponseReceived(Video video)
{
Thread th = new Thread(() => UpdateVideoID(video.Id));
th.Start();
Console.WriteLine("Video id '{0}' was successfully uploaded.", video.Id);
}

Image does not display in gallery after download

I am developing a Xamarin app which retrives info from DB, take/choose photo and upload them to remote server, display this images from the remote server and the user can delete them by tap on and press a button and download the images from the remote server to the local device.
Everything works without problem, but when I download the image and after I go to the gallery for check it, the image does not appear, whereas I can see it and open in the file explorer. When I reboot the phone, the image appear in the gallery.
Below my current button download method:
private void button_download_image_Clicked(object sender, EventArgs e)
{
Uri image_url_format = new Uri(image_url);
WebClient webClient = new WebClient();
try
{
byte[] bytes_image = webClient.DownloadData(image_url_format);
Stream image_stream = new MemoryStream(bytes_image);
string dest_folder = Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDownloads).ToString();
string file_name = System.IO.Path.GetFileName(image_url_format.LocalPath);
string dest_path = System.IO.Path.Combine(dest_folder, file_name);
using (var fileStream = new FileStream(dest_path, FileMode.Create, FileAccess.Write))
{
image_stream.CopyTo(fileStream);
}
}
catch (Exception ex)
{
DisplayAlert("Error", ex.ToString(), "OK");
}
DisplayAlert("Alert", "Download completed!", "OK");
}
I tried in another device, but I got the same behavior.
Probably there is a sort of thing which does not refresh the gallery.
Any idea how to force the gallery to refresh or something similar?

You need to refresh your gallery after inserting or deleting any pictures in storage.
You can try this.
var mediaScanIntent = new Intent(Intent.ActionMediaScannerScanFile);
mediaScanIntent.SetData(Android.Net.Uri.FromFile(new Java.IO.File(dest_path)));
Xamarin.Forms.Forms.Context.SendBroadcast(mediaScanIntent);
Add these lines below your code.
Make it like
private void button_download_image_Clicked(object sender, EventArgs e)
{
Uri image_url_format = new Uri(image_url);
WebClient webClient = new WebClient();
try
{
byte[] bytes_image = webClient.DownloadData(image_url_format);
Stream image_stream = new MemoryStream(bytes_image);
string dest_folder = Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDownloads).ToString();
string file_name = System.IO.Path.GetFileName(image_url_format.LocalPath);
string dest_path = System.IO.Path.Combine(dest_folder, file_name);
using (var fileStream = new FileStream(dest_path, FileMode.Create, FileAccess.Write))
{
image_stream.CopyTo(fileStream);
}
var mediaScanIntent = new Intent(Intent.ActionMediaScannerScanFile);
mediaScanIntent.SetData(Android.Net.Uri.FromFile(new Java.IO.File(dest_path)));
//for old xamarin forms version
Xamarin.Forms.Forms.Context.SendBroadcast(mediaScanIntent);
//for new xamarin forms version
//Android.App.Application.SendBroadcast(mediaScanIntent);
}
catch (Exception ex)
{
DisplayAlert("Error", ex.ToString(), "OK");
return;
}
DisplayAlert("Alert", "Download completed!", "OK");
}

You need to just refresh the file you have downloaded. It's helpful.
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT){
Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
File f = new File("file://"+ Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES));
Uri contentUri = Uri.fromFile(f);
mediaScanIntent.setData(contentUri);
this.sendBroadcast(mediaScanIntent);
}else{
sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.parse("file://" + Environment.getExternalStorageDirectory())));
}

Make sure required permission given on both platforms.
Use in your class:
bool success = await DependencyService.Get<IPhotoLibrary>().SavePhotoAsync(data, folder, filename);
Common Interface
public interface IPhotoLibrary
{
Task<bool> SavePhotoAsync(byte[] data, string folder, string filename);
}
In Android service
public async Task<bool> SavePhotoAsync(byte[] data, string folder, string filename)
{
try
{
File picturesDirectory = Environment.GetExternalStoragePublicDirectory(Environment.DirectoryPictures);
File folderDirectory = picturesDirectory;
if (!string.IsNullOrEmpty(folder))
{
folderDirectory = new File(picturesDirectory, folder);
folderDirectory.Mkdirs();
}
using (File bitmapFile = new File(folderDirectory, filename))
{
bitmapFile.CreateNewFile();
using (FileOutputStream outputStream = new FileOutputStream(bitmapFile))
{
await outputStream.WriteAsync(data);
}
// Make sure it shows up in the Photos gallery promptly.
MediaScannerConnection.ScanFile(MainActivity.Instance,
new string[] { bitmapFile.Path },
new string[] { "image/png", "image/jpeg" }, null);
}
}
catch (System.Exception ex)
{
return false;
}
return true;
}
In iOS service:
public Task<bool> SavePhotoAsync(byte[] data, string folder, string filename)
{
NSData nsData = NSData.FromArray(data);
UIImage image = new UIImage(nsData);
TaskCompletionSource<bool> taskCompletionSource = new TaskCompletionSource<bool>();
image.SaveToPhotosAlbum((UIImage img, NSError error) =>
{
taskCompletionSource.SetResult(error == null);
});
return taskCompletionSource.Task;
}
also you can refer this one just to save an image and to reflect it in media, no need to use skiasharp for that. https://learn.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/graphics/skiasharp/bitmaps/saving
Hope this may resolve your issue.

Refer to Blu's answer,
I changed this Xamarin.Forms.Forms.Context.SendBroadcast(mediaScanIntent); to Android.App.Application.Context.SendBroadcast(mediaScanIntent); and all works.

Why value does not fall within the expected range when setting Value Changed for Gatt Characteristic

I would like to keep on reading characteristic/set value changed event handlers for characteristics from my BLE 4.0 device, by using the ValueChanged callback in Universal Windows Platform C# in Visual Studio 2017.
I followed some tutorial from these sites: Damian Blog's Windows Universal with BLE, Bluetooth Gatt's Git Hub, Bluetooth Generic Attribute Profile - Heart Rate Service and Dr. Jukka's mobile Blog on BLE. All of them are using ValueChanged and I have tried to follow what they did.
Unfortunately, instead of ValueChanged being triggered, I receive the following error when using the ValueChanged callback.
System.ArgumentException: 'Value does not fall within the expected range.'
This line of code is producing the error:
characteristic.ValueChanged += Oncharacteristic_ValueChanged;
Here is more details of my source code:
NOTE: I am using COM 7 for my dongler and my program could discover the BLE's device name, and could discover the Uuid of the services and characteristics.
public List<string> serviceList = new List<string>();
public List<string> characteristicList = new List<string>();
public BluetoothLEDevice myDevice { get; set; }
public MainPage()
{
this.InitializeComponent();
}
private async void Page_Loaded(object sender, RoutedEventArgs e)
{
// Find the com port
string selector = SerialDevice.GetDeviceSelector("COM7");
DeviceInformationCollection devices = await DeviceInformation.FindAllAsync(selector);
if (devices.Count > 0)
{
var dialog = new MessageDialog("Com Device found");
await dialog.ShowAsync();
DeviceInformation deviceInfo = devices[0];
SerialDevice serialDevice = await SerialDevice.FromIdAsync(deviceInfo.Id);
serialDevice.BaudRate = 9600;
serialDevice.DataBits = 8;
serialDevice.StopBits = SerialStopBitCount.One;
serialDevice.Parity = SerialParity.None;
}
else
{
MessageDialog popup = new MessageDialog("Sorry, no device found.");
await popup.ShowAsync();
}
// After com port is found, search for device
foreach (DeviceInformation di in await DeviceInformation.FindAllAsync(BluetoothLEDevice.GetDeviceSelector()))
{
BluetoothLEDevice bleDevice = await BluetoothLEDevice.FromIdAsync(di.Id);
// Display BLE device name
var dialogBleDeviceName = new MessageDialog("BLE Device Name " + bleDevice.Name);
await dialogBleDeviceName.ShowAsync();
myDevice = bleDevice;
}
// Check device connection
myDevice.ConnectionStatusChanged += OnConnectionStatusChanged;
foreach (var service in myDevice.GattServices)
{
serviceList.Add(service.Uuid.ToString());
// Verify if service is discovered by displaying a popup
MessageDialog serviceUuidPopUp = new MessageDialog("Adding Service Uuid to list " + service.Uuid.ToString() );
await serviceUuidPopUp.ShowAsync();
foreach (var characteristic in service.GetAllCharacteristics())
{
var characteristicUuid = characteristic.Uuid.ToString().ToLowerInvariant();
characteristicList.Add(characteristicUuid);
// Verify if characteristic is discovered by displaying a popup
MessageDialog charUuidPopUp = new MessageDialog("Adding characteristic Uuid to list " + characteristicUuid);
await charUuidPopUp.ShowAsync();
// set value changed event handlers for characteristics
characteristic.ValueChanged += Oncharacteristic_ValueChanged;
}
}
}
private void OnConnectionStatusChanged(BluetoothLEDevice sender, object args)
{
if (sender.ConnectionStatus == BluetoothConnectionStatus.Connected)
{
System.Diagnostics.Debug.WriteLine("Connected");
}
else
{
System.Diagnostics.Debug.WriteLine("Disconnected");
}
}
private void Oncharacteristic_ValueChanged(GattCharacteristic sender, GattValueChangedEventArgs args)
{
byte[] data = new byte[args.CharacteristicValue.Length];
DataReader.FromBuffer(
args.CharacteristicValue).ReadBytes(data);
string text = Encoding.UTF8.GetString(data, 0, data.Length);
}
UPDATE 1
I tried to check Characteristic Properties before set value changed event handlers for my characteristics by following the answer given by rudi belt on SO.
if (characteristic.CharacteristicProperties == (GattCharacteristicProperties.Read | GattCharacteristicProperties.Notify))
{
characteristic.ValueChanged += Oncharacteristic_ValueChanged;
}
Unfortunately, this IF statement is not executed.
UPDATE 2
I have tried to remove ALL the codes inside Oncharacteristic_ValueChanged method. But it still gives me the same error
System.ArgumentException: 'Value does not fall within the expected range.'
I have been spending a lot of time trying to solve this problem. I will be very happy if anyone can help me on this. Thank you!

Reading your efforts in the former question I can provide a working example, but first some explanation.
myDevice.ConnectionStatusChanged is not needed, it is only used to notice a connection is lost or connected. You have to connect to your device first and handle things in the connection method.
After you have succeeded in connecting you have to get the service that contains the characteristic you want to use for read, write, notify or indicate.
When you have selected the service You can get the characteristics of that service.
Select the characteristic by Uuid, or in my example with CharacteristicProperties.HasFlag.
This flag in my example is Notify.
In the code comments you find extra info.
using System;
using System.Diagnostics;
using System.Threading.Tasks;
using Windows.Devices.Bluetooth;
using Windows.Devices.Bluetooth.GenericAttributeProfile;
using Windows.Devices.Enumeration;
using Windows.UI.Popups;
using Windows.UI.Xaml.Controls;
namespace App1
{
public sealed partial class MainPage : Page
{
GattDeviceServicesResult serviceResult = null;
private BluetoothLEDevice myDevice;
private GattCharacteristic selectedCharacteristic;
public MainPage()
{
this.InitializeComponent();
ConnectDevice();
}
private async void ConnectDevice()
{
//This works only if your device is already paired!
foreach (DeviceInformation di in await DeviceInformation.FindAllAsync(BluetoothLEDevice.GetDeviceSelector()))
{
BluetoothLEDevice bleDevice = await BluetoothLEDevice.FromIdAsync(di.Id);
// Display BLE device name
var dialogBleDeviceName = new MessageDialog("BLE Device Name " + bleDevice.Name);
await dialogBleDeviceName.ShowAsync();
myDevice = bleDevice;
}
if (myDevice != null)
{
int servicesCount = 3;//Fill in the amount of services from your device!!!!!
int tryCount = 0;
bool connected = false;
while (!connected)//This is to make sure all services are found.
{
tryCount++;
serviceResult = await myDevice.GetGattServicesAsync();
if (serviceResult.Status == GattCommunicationStatus.Success && serviceResult.Services.Count >= servicesCount)
{
connected = true;
Debug.WriteLine("Connected in " + tryCount + " tries");
}
if (tryCount > 5)//make this larger if faild
{
Debug.WriteLine("Failed to connect to device ");
return;
}
}
if (connected)
{
for (int i = 0; i < serviceResult.Services.Count; i++)
{
var service = serviceResult.Services[i];
//This must be the service that contains the Gatt-Characteristic you want to read from or write to !!!!!!!.
string myServiceUuid = "0000ffe0-0000-1000-8000-00805f9b34fb";
if (service.Uuid.ToString() == myServiceUuid)
{
Get_Characteriisics(service);
break;
}
}
}
}
}
private async void Get_Characteriisics(GattDeviceService myService)
{
var CharResult = await myService.GetCharacteristicsAsync();
if (CharResult.Status == GattCommunicationStatus.Success)
{
foreach (GattCharacteristic c in CharResult.Characteristics)
{
if (c.CharacteristicProperties.HasFlag(GattCharacteristicProperties.Notify))
{
selectedCharacteristic = c;
break;
}
}
try
{
// Write the ClientCharacteristicConfigurationDescriptor in order for server to send notifications.
var result = await selectedCharacteristic.WriteClientCharacteristicConfigurationDescriptorAsync(
GattClientCharacteristicConfigurationDescriptorValue.Notify);
if (result == GattCommunicationStatus.Success)
{
var dialogNotifications = new MessageDialog("Successfully registered for notifications");
await dialogNotifications.ShowAsync();
selectedCharacteristic.ValueChanged += SelectedCharacteristic_ValueChanged;
}
else
{
var dialogNotifications = new MessageDialog($"Error registering for notifications: {result}");
await dialogNotifications.ShowAsync();
}
}
catch (Exception ex)
{
// This usually happens when not all characteristics are found
// or selected characteristic has no Notify.
var dialogNotifications = new MessageDialog(ex.Message);
await dialogNotifications.ShowAsync();
await Task.Delay(100);
Get_Characteriisics(myService); //try again
//!!! Add a max try counter to prevent infinite loop!!!!!!!
}
}
else
{
var dialogNotifications = new MessageDialog("Restricted service. Can't read characteristics");
await dialogNotifications.ShowAsync();
}
}
private void SelectedCharacteristic_ValueChanged(GattCharacteristic sender, GattValueChangedEventArgs args)
{
}
}
}
If you have problems with this code feel free to ask in comments.

The process cannot access the file because it is being used by another process

I am running a program where a file gets uploaded to a folder in IIS,and then is processed to extract some values from it. I use a WCF service to perform the process, and BackgroundUploader to upload the file to IIS. However, after the upload process is complete, I get the error "The process cannot access the file x because it is being used by another process." Based on similar questions asked here, I gathered that the file concerned needs to be in a using statement. I tried to modify my code to the following, but it didn't work, and I am not sure if it is even right.
namespace App17
{
public sealed partial class MainPage : Page, IDisposable
{
private CancellationTokenSource cts;
public void Dispose()
{
if (cts != null)
{
cts.Dispose();
cts = null;
}
GC.SuppressFinalize(this);
}
public MainPage()
{
this.InitializeComponent();
cts = new CancellationTokenSource();
}
public async void Button_Click(object sender, RoutedEventArgs e)
{
try
{
Uri uri = new Uri(serverAddressField.Text.Trim());
FileOpenPicker picker = new FileOpenPicker();
picker.FileTypeFilter.Add("*");
StorageFile file = await picker.PickSingleFileAsync();
using (var stream = await file.OpenAsync(FileAccessMode.Read))
{
GlobalClass.filecontent = file.Name;
GlobalClass.filepath = file.Path;
BackgroundUploader uploader = new BackgroundUploader();
uploader.SetRequestHeader("Filename", file.Name);
UploadOperation upload = uploader.CreateUpload(uri, file);
await HandleUploadAsync(upload, true);
stream.Dispose();
}
}
catch (Exception ex)
{
string message = ex.ToString();
var dialog = new MessageDialog(message);
await dialog.ShowAsync();
Log(message);
}
}
private void CancelAll(object sender, RoutedEventArgs e)
{
Log("Canceling all active uploads");
cts.Cancel();
cts.Dispose();
cts = new CancellationTokenSource();
}
private async Task HandleUploadAsync(UploadOperation upload, bool start)
{
try
{
Progress<UploadOperation> progressCallback = new Progress<UploadOperation>(UploadProgress);
if (start)
{
await upload.StartAsync().AsTask(cts.Token, progressCallback);
}
else
{
// The upload was already running when the application started, re-attach the progress handler.
await upload.AttachAsync().AsTask(cts.Token, progressCallback);
}
ResponseInformation response = upload.GetResponseInformation();
Log(String.Format("Completed: {0}, Status Code: {1}", upload.Guid, response.StatusCode));
cts.Dispose();
}
catch (TaskCanceledException)
{
Log("Upload cancelled.");
}
catch (Exception ex)
{
string message = ex.ToString();
var dialog = new MessageDialog(message);
await dialog.ShowAsync();
Log(message);
}
}
private void Log(string message)
{
outputField.Text += message + "\r\n";
}
private async void LogStatus(string message)
{
var dialog = new MessageDialog(message);
await dialog.ShowAsync();
Log(message);
}
private void UploadProgress(UploadOperation upload)
{
BackgroundUploadProgress currentProgress = upload.Progress;
MarshalLog(String.Format(CultureInfo.CurrentCulture, "Progress: {0}, Status: {1}", upload.Guid,
currentProgress.Status));
double percentSent = 100;
if (currentProgress.TotalBytesToSend > 0)
{
percentSent = currentProgress.BytesSent * 100 / currentProgress.TotalBytesToSend;
}
MarshalLog(String.Format(CultureInfo.CurrentCulture,
" - Sent bytes: {0} of {1} ({2}%), Received bytes: {3} of {4}", currentProgress.BytesSent,
currentProgress.TotalBytesToSend, percentSent, currentProgress.BytesReceived, currentProgress.TotalBytesToReceive));
if (currentProgress.HasRestarted)
{
MarshalLog(" - Upload restarted");
}
if (currentProgress.HasResponseChanged)
{
MarshalLog(" - Response updated; Header count: " + upload.GetResponseInformation().Headers.Count);
}
}
private void MarshalLog(string value)
{
var ignore = this.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
{
Log(value);
});
}
}
}
After this is done, the file name is sent to a WCF service which will access and process the uploaded file to extract certain values. It is at this point I receive the error. I would truly appreciate some help.
public async void Extract_Button_Click(object sender, RoutedEventArgs e)
{
ServiceReference1.Service1Client MyService = new ServiceReference1.Service1Client();
string filename = GlobalClass.filecontent;
string filepath = #"C:\Users\R\Documents\Visual Studio 2015\Projects\WCF\WCF\Uploads\"+ filename;
bool x = await MyService.ReadECGAsync(filename, filepath);
}
EDIT: Code before I added the using block
try
{
Uri uri = new Uri(serverAddressField.Text.Trim());
FileOpenPicker picker = new FileOpenPicker();
picker.FileTypeFilter.Add("*");
StorageFile file = await picker.PickSingleFileAsync();
GlobalClass.filecontent = file.Name;
GlobalClass.filepath = file.Path;
BackgroundUploader uploader = new BackgroundUploader();
uploader.SetRequestHeader("Filename", file.Name);
UploadOperation upload = uploader.CreateUpload(uri, file);
await HandleUploadAsync(upload, true);
}

When you work with stream writers you actually create a process, which you can close it from task manager. And after stream.Dispose() put stream.Close().
This should solve your problem.

You should also close the stream that writes the file to disk (look at your implementation of CreateUpload).

i got such error in DotNet Core 2 using this code:
await file.CopyToAsync(new FileStream(fullFileName, FileMode.Create));
counter++;
and this is how I managed to get rid of message (The process cannot access the file x because it is being used by another process):
using (FileStream DestinationStream = new FileStream(fullFileName, FileMode.Create))
{
await file.CopyToAsync(DestinationStream);
counter++;
}