hello friends i am new in uwp.
i want to scan a document. i am installed the NTwain 3.6.0 Package from NuGet. now my question is how to get the scanner list and scan the document.
What I have tried:
dont know..................................................... public DeviceWatcherHelper( ObservableCollection<DeviceInformationDisplay> resultCollection, CoreDispatcher dispatcher) this .resultCollection = resultCollection; this .dispatcher = dispatcher; public delegate void DeviceChangedHandler(DeviceWatcher deviceWatcher, string id); public event DeviceChangedHandler DeviceChanged; public DeviceWatcher DeviceWatcher => deviceWatcher; public bool UpdateStatus = true ; public void StartWatcher(DeviceWatcher deviceWatcher) this .deviceWatcher = deviceWatcher; // Connect events to update our collection as the watcher report results. deviceWatcher.Added += Watcher_DeviceAdded; deviceWatcher.Updated += Watcher_DeviceUpdated; deviceWatcher.Removed += Watcher_DeviceRemoved; // deviceWatcher.EnumerationCompleted += Watcher_EnumerationCompleted; // deviceWatcher.Stopped += Watcher_Stopped; deviceWatcher.Start(); public void StopWatcher() // Since the device watcher runs in the background, it is possible that // a notification is "in flight" at the time we stop the watcher. // In other words, it is possible for the watcher to become stopped while a // handler is running, or for a handler to run after the watcher has stopped. if (IsWatcherStarted(deviceWatcher)) // We do not null out the deviceWatcher yet because we want to receive // the Stopped event. deviceWatcher.Stop(); public void Reset() if (deviceWatcher != null ) StopWatcher(); deviceWatcher = null ; DeviceWatcher deviceWatcher = null ; ObservableCollection<DeviceInformationDisplay> resultCollection; CoreDispatcher dispatcher; static bool IsWatcherStarted(DeviceWatcher watcher) return (watcher.Status == DeviceWatcherStatus.Started) || (watcher.Status == DeviceWatcherStatus.EnumerationCompleted); public bool IsWatcherRunning() if (deviceWatcher == null ) return false ; DeviceWatcherStatus status = deviceWatcher.Status; return (status == DeviceWatcherStatus.Started) || (status == DeviceWatcherStatus.EnumerationCompleted) || (status == DeviceWatcherStatus.Stopping); private async void Watcher_DeviceAdded(DeviceWatcher sender, DeviceInformation deviceInfo) // Since we have the collection databound to a UI element, we need to update the collection on the UI thread. await dispatcher.RunAsync(CoreDispatcherPriority.Low, () => // Watcher may have stopped while we were waiting for our chance to run. if (IsWatcherStarted(sender)) resultCollection.Add( new DeviceInformationDisplay(deviceInfo )); // RaiseDeviceChanged(sender, deviceInfo.Id); private async void Watcher_DeviceUpdated(DeviceWatcher sender, DeviceInformationUpdate deviceInfoUpdate) // Since we have the collection databound to a UI element, we need to update the collection on the UI thread. await dispatcher.RunAsync(CoreDispatcherPriority.Low, () => // Watcher may have stopped while we were waiting for our chance to run. if (IsWatcherStarted(sender)) // Find the corresponding updated DeviceInformation in the collection and pass the update object // to the Update method of the existing DeviceInformation. This automatically updates the object // for us. foreach (DeviceInformationDisplay deviceInfoDisp in resultCollection) if (deviceInfoDisp.Id == deviceInfoUpdate.Id) deviceInfoDisp.Update(deviceInfoUpdate); // RaiseDeviceChanged(sender, deviceInfoUpdate.Id); break ; private async void Watcher_DeviceRemoved(DeviceWatcher sender, DeviceInformationUpdate deviceInfoUpdate) // Since we have the collection databound to a UI element, we need to update the collection on the UI thread. await dispatcher.RunAsync(CoreDispatcherPriority.Low, () => // Watcher may have stopped while we were waiting for our chance to run. if (IsWatcherStarted(sender)) // Find the corresponding DeviceInformation in the collection and remove it foreach (DeviceInformationDisplay deviceInfoDisp in resultCollection) if (deviceInfoDisp.Id == deviceInfoUpdate.Id) resultCollection.Remove(deviceInfoDisp); break ; // RaiseDeviceChanged(sender, deviceInfoUpdate.Id); private async void Watcher_EnumerationCompleted(DeviceWatcher sender, object obj) await dispatcher.RunAsync(CoreDispatcherPriority.Low, () => // RaiseDeviceChanged(sender, string.Empty); private async void Watcher_Stopped(DeviceWatcher sender, object obj) await dispatcher.RunAsync(CoreDispatcherPriority.Low, () => // RaiseDeviceChanged(sender, string.Empty); on Scan Document Page XAML code :
<Border extensions:Mouse.Cursor= " Hand" Margin= " 42,10,76,0" BorderThickness= " 1" BorderBrush= " #E1E1E1" CornerRadius= " 5" VerticalAlignment= " Stretch" > <ComboBox Padding= " 5 0 0 0" Name= " CmbScannerList" extensions:Mouse.Cursor= " Hand" SelectedValuePath= " rid" BorderBrush= " Transparent" BorderThickness= " 0" FontSize= " 13" FontWeight= " Light" FontFamily= " {StaticResource inventoryRegularFont}" TabIndex= " 8" Header= " " PlaceholderForeground= " #414042" PlaceholderText= " Connected Devices List " HorizontalAlignment= " Left" VerticalAlignment= " Top" Margin= " 0,-1,0,0" Width= " 532" Height= " 57" > <ComboBox.ItemTemplate> <DataTemplate x:DataType= " local:DeviceInformationDisplay" > <TextBlock Name= " {x:Bind Id }" Text= " {x:Bind Name }" /> </ DataTemplate > </ ComboBox.ItemTemplate > </ ComboBox > </ Border > scan document page code behind:
public sealed partial class ScanDocumentPage : Page private DeviceWatcherHelper deviceWatcherHelper; private ObservableCollection<DeviceInformationDisplay> resultCollection = new ObservableCollection<DeviceInformationDisplay>(); public ScanDocumentPage() this .InitializeComponent(); deviceWatcherHelper = new DeviceWatcherHelper(resultCollection, Dispatcher); StartWatcher(); private void StartWatcher() resultCollection.Clear(); DeviceWatcher deviceWatcher; deviceWatcher = DeviceInformation.CreateWatcher(DeviceClass.All ); // here you can set the All or ImageScanner or Audiodevices deviceWatcherHelper.StartWatcher(deviceWatcher); protected override void OnNavigatedTo(NavigationEventArgs e) CmbScannerList.ItemsSource = resultCollection; // here you can bind the devices list.

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