I'm wondering if exists a better way to complete a worker subject. To do this, a complete when all tasks have run.
Here is the code:
export class WorkerSubject<T> extends Subject<T> {
protected worker: Worker;
protected jobs = 0;
protected finish = false;
constructor(callback: Function, async = false) {
super();
this.worker =
async ? createWorkerPostMessage(callback) : createStaticWorker(callback);
this.worker.onmessage = e => {
this.jobs--;
super.next(e.data);
if (this.jobs === 0 && this.finish) {
super.complete();
this.worker.terminate();
}
};
this.worker.onerror = e => {
super.error(e);
this.worker.terminate();
};
}
next(value: any): void {
if (this.finish) {
throw new Error('WorkerSubject complete, no more values can be emited.')
}
this.jobs++;
this.worker.postMessage(value);
}
complete() {
this.finish = true;
}
}
Any idea to improve this?
Related
How can I avoid invoking of the same event multiple times when a button is clicked rapidly.
Below is the code:
I've created a Custom Delegate Command as below
View Model
namespace TestProject.ViewModels
{
public class TestViewModel
{
public CustomDelegateCommand MenuButtonClickCommand { get; set; }
public TestViewModel()
{
MenuButtonClickCommand = new CustomDelegateCommand (async () => await ShowMenuAction());
}
private async Task ShowMenuAction()
{
//await some stuff
}
}
}
CustomDelegateCommand.cs
public class CustomDelegateTimerCommand : DelegateCommand
{
public CustomDelegateTimerCommand(Action executeMethod, Func<bool> validateMethod, Action onBusy = default(Action)) : base(executeMethod)
{
BackgroundTaskWaitHandle = new EventWaitHandle(true, EventResetMode.ManualReset);
_validateMethod = validateMethod;
_onBusy = onBusy;
}
}
The problem I'm facing is whenever a user clicks on the button rapidly, the menu list popup is opening multiple times.
I have lot of commands in my project and I need a solution that would work globally.
I tried to resolve the issue like below using ObservesCanExecute() but I don't like the idea of creating a separate variable for every command as I've a lot of commands in my project and I don't want the button to go in to disabled state when CanExecute = false.
ViewModel
MenuButtonClickCommand = new CustomDelegateCommand (async () => await ShowMenuAction().ObservesCanExecute(() => CanExecute );
private async Task ShowMenuAction()
{
CanExecute = false;
//await some stuff
CanExecute = true;
}
Any help is much appreciated!
There are 2 solutions to it. One is when you use, MVVM other is when you dont.
The non MVVM solution is delaying the execution of method for certain amount of time, like this:
public class SingleClickListener
{
private bool hasClicked;
private Action<object, EventArgs> _setOnClick;
public SingleClickListener(Action<object, EventArgs> setOnClick)
{
_setOnClick = setOnClick;
}
public void OnClick(object v, EventArgs e)
{
if (!hasClicked)
{
_setOnClick(v, e);
hasClicked = true;
}
reset();
}
private void reset()
{
Android.OS.Handler mHandler = new Android.OS.Handler();
mHandler.PostDelayed(new Action(() => { hasClicked = false; }), 500);
}
}
And then when you subscribe the onclick event:
var buttonNa = new Button { Text = "Test Button" };
buttonNa.Clicked += new SingleClickListener((sender, e) =>
{
//DO something
}).OnClick;
The Mvvm solution is bit more complicated, but its not as hacky.
TestCommand = new Command(
execute: async () =>
{
IsEditing = true;
RefreshCanExecutes();
//Fire Method
TestMethod();
},
canExecute: () =>
{
return !IsEditing;
});
public void RefreshCanExecutes()
{
(TestCommand as Command).ChangeCanExecute();
}
public void TestMethod()
{
//DO something
IsEditing = false;
RefreshCanExecutes();
}
Obviously dont forget to bind your commands to xaml :)
also second solution actually disables the button, so user cannot even tap it, first one however only ignores further taps, till time delay has finished.
Create a new class which inherits from Xamarin.Forms.Button with delay in click event, than add it to your xmal.
public class DelayedButton : Xamarin.Forms.Button
{
public DelayedButton()
{
this.Clicked += DelayedButton_Clicked;
}
async private void DelayedButton_Clicked(object sender, EventArgs e)
{
this.IsEnabled = false;
await Task.Delay(Delay);
this.IsEnabled = true;
}
public int Delay { get; set; } = 500;
}
In XAML：
<yourNameSpace:DelayedButton Delay="300" Text="DelayedButton" Command="{Binding ClickCommand}"/>
I am trying to implement below java code in c# referring to Android documentation
List<String> skuList = new ArrayList<> ();
skuList.add("premium_upgrade");
skuList.add("gas");
SkuDetailsParams.Builder params = SkuDetailsParams.newBuilder();
params.setSkusList(skuList).setType(SkuType.INAPP);
billingClient.querySkuDetailsAsync(params.build(),
new SkuDetailsResponseListener() {
#Override
public void onSkuDetailsResponse(BillingResult billingResult,
List<SkuDetails> skuDetailsList) {
// Process the result.
}
});
I have here 2 questions. I thought that i would run this code on a separate thread than UI thread like below to keep my ui responsive while network connection is done. is that the correct approach? QuerySkuDetailsAsync is called async but doesnt implement as async. how should this be working and how to handle in c# because it will fire and forget but Listener to handle the response.
public async Task<List<InAppBillingProduct>> GetProductsAsync(List<string> ProductIds)
{
var getSkuDetailsTask = Task.Factory.StartNew(() =>
{
var prms = SkuDetailsParams.NewBuilder();
var type = BillingClient.SkuType.Inapp;
prms.SetSkusList(ProductIds).SetType(type);
BillingClient.QuerySkuDetailsAsync(prms.Build(), new SkuDetailsResponseListener());
return InAppBillingProducts;
});
return await getSkuDetailsTask;
}
2nd question regarding how to handle with the listener as below. How do I return value from the listener. I need return list of InAppBillingProduct object.
public class SkuDetailsResponseListener : Java.Lang.Object, ISkuDetailsResponseListener
{
public void OnSkuDetailsResponse(BillingResult billingResult, IList<SkuDetails> skus)
{
if (billingResult.ResponseCode == BillingResponseCode.Ok)
{
// get list of Products here and return
}
}
}
FYI. This is how I did it. This is not a complete code but this will give you and idea.
Listener - PCL
============
private async Task EventClicked()
{
var skuList = new List<string>();
skuList.Add("[nameofsubscriptionfoundinyourgoogleplay]");
if (await _billingClientLifecycle.Initialize(skuList, DisconnectedConnection))
{
var firstProduct = _billingClientLifecycle?.ProductsInStore?.FirstOrDefault();
if (firstProduct != null)
{
//purchase here
}
}
}
private void DisconnectedConnection()
{
//Todo.alfon. handle disconnection here...
}
Interface - PCL
===========
public interface IInAppBillingMigratedNew
{
List<InAppBillingPurchase> PurchasedProducts { get; set; }
List<InAppBillingProduct> ProductsInStore { get; set; }
Task<bool> Initialize(List<String> skuList, Action onDisconnected = null);
}
Dependency - Platform Droid
===============
[assembly: XF.Dependency(typeof(InAppBillingMigratedNew))]
public class InAppBillingMigratedNew : Java.Lang.Object, IBillingClientStateListener
, ISkuDetailsResponseListener, IInAppBillingMigratedNew
{
private Activity Context => CrossCurrentActivity.Current.Activity
?? throw new NullReferenceException("Current Context/Activity is null");
private BillingClient _billingClient;
private List<string> _skuList = new List<string>();
private TaskCompletionSource<bool> _tcsInitialized;
private Action _disconnectedAction;
private Dictionary<string, SkuDetails> _skusWithSkuDetails = new Dictionary<string, SkuDetails>();
public List<InAppBillingPurchase> PurchasedProducts { get; set; }
public List<InAppBillingProduct> ProductsInStore { get; set; }
public IntPtr Handle => throw new NotImplementedException();
public Task<bool> Initialize(List<string> skuList, Action disconnectedAction = null)
{
_disconnectedAction = disconnectedAction;
_tcsInitialized = new TaskCompletionSource<bool>();
var taskInit = _tcsInitialized.Task;
_skuList = skuList;
_billingClient = BillingClient.NewBuilder(Context)
.SetListener(this)
.EnablePendingPurchases()
.Build();
if (!_billingClient.IsReady)
{
_billingClient.StartConnection(this);
}
return taskInit;
}
#region IBillingClientStateListener
public void OnBillingServiceDisconnected()
{
Console.WriteLine($"Connection disconnected.");
_tcsInitialized?.TrySetResult(false);
_disconnectedAction?.Invoke();
}
public void OnBillingSetupFinished(BillingResult billingResult)
{
var responseCode = billingResult.ResponseCode;
var debugMessage = billingResult.DebugMessage;
if (responseCode == BillingResponseCode.Ok)
{
QuerySkuDetails();
QueryPurchases();
_tcsInitialized?.TrySetResult(true);
}
else
{
Console.WriteLine($"Failed connection {debugMessage}");
_tcsInitialized?.TrySetResult(false);
}
}
#endregion
#region ISkuDetailsResponseListener
public void OnSkuDetailsResponse(BillingResult billingResult, IList<SkuDetails> skuDetailsList)
{
if (billingResult == null)
{
Console.WriteLine("onSkuDetailsResponse: null BillingResult");
return;
}
var responseCode = billingResult.ResponseCode;
var debugMessage = billingResult.DebugMessage;
switch (responseCode)
{
case BillingResponseCode.Ok:
if (skuDetailsList == null)
{
_skusWithSkuDetails.Clear();
}
else
{
if (skuDetailsList.Count > 0)
{
ProductsInStore = new List<InAppBillingProduct>();
}
foreach (var skuDetails in skuDetailsList)
{
_skusWithSkuDetails.Add(skuDetails.Sku, skuDetails);
//ToDo.alfon. make use mapper here
ProductsInStore.Add(new InAppBillingProduct
{
Name = skuDetails.Title,
Description = skuDetails.Description,
ProductId = skuDetails.Sku,
CurrencyCode = skuDetails.PriceCurrencyCode,
LocalizedIntroductoryPrice = skuDetails.IntroductoryPrice,
LocalizedPrice = skuDetails.Price,
MicrosIntroductoryPrice = skuDetails.IntroductoryPriceAmountMicros,
MicrosPrice = skuDetails.PriceAmountMicros
});
}
}
break;
case BillingResponseCode.ServiceDisconnected:
case BillingResponseCode.ServiceUnavailable:
case BillingResponseCode.BillingUnavailable:
case BillingResponseCode.ItemUnavailable:
case BillingResponseCode.DeveloperError:
case BillingResponseCode.Error:
Console.WriteLine("onSkuDetailsResponse: " + responseCode + " " + debugMessage);
break;
case BillingResponseCode.UserCancelled:
Console.WriteLine("onSkuDetailsResponse: " + responseCode + " " + debugMessage);
break;
// These response codes are not expected.
case BillingResponseCode.FeatureNotSupported:
case BillingResponseCode.ItemAlreadyOwned:
case BillingResponseCode.ItemNotOwned:
default:
Console.WriteLine("onSkuDetailsResponse: " + responseCode + " " + debugMessage);
break;
}
}
#endregion
#region Helper Methods Private
private void ProcessPurchases(List<Purchase> purchasesList)
{
if (purchasesList == null)
{
Console.WriteLine("No purchases done.");
return;
}
if (IsUnchangedPurchaseList(purchasesList))
{
Console.WriteLine("Purchases has not changed.");
return;
}
_purchases.AddRange(purchasesList);
PurchasedProducts = _purchases.Select(sku => new InAppBillingPurchase
{
PurchaseToken = sku.PurchaseToken
})?.ToList();
if (purchasesList != null)
{
LogAcknowledgementStatus(purchasesList);
}
}
private bool IsUnchangedPurchaseList(List<Purchase> purchasesList)
{
// TODO: Optimize to avoid updates with identical data.
return false;
}
private void LogAcknowledgementStatus(List<Purchase> purchasesList)
{
int ack_yes = 0;
int ack_no = 0;
foreach (var purchase in purchasesList)
{
if (purchase.IsAcknowledged)
{
ack_yes++;
}
else
{
ack_no++;
}
}
//Log.d(TAG, "logAcknowledgementStatus: acknowledged=" + ack_yes +
// " unacknowledged=" + ack_no);
}
private void QuerySkuDetails()
{
var parameters = SkuDetailsParams
.NewBuilder()
.SetType(BillingClient.SkuType.Subs)
.SetSkusList(_skuList)
.Build();
_billingClient.QuerySkuDetailsAsync(parameters, this);
}
private void QueryPurchases()
{
if (!_billingClient.IsReady)
{
Console.WriteLine("queryPurchases: BillingClient is not ready");
}
var result = _billingClient.QueryPurchases(BillingClient.SkuType.Subs);
ProcessPurchases(result?.PurchasesList?.ToList());
}
#endregion
}
I trying to scan QR-codes in my app. It works sometimes and sometimes not. The feeling is that it doesn't work when something is loading on another thread. For example, if I press the scan button when nearby stores still are loading. Often it works if I wait.
The video capture is working because I will see the preview.
Here is my code:
private bool resultFound;
public ScannerView()
{
InitializeComponent();
On<Xamarin.Forms.PlatformConfiguration.iOS>().SetUseSafeArea(false);
view = new UIView();
ScannerArea.Children.Add(view);
}
void HandleAVRequestAccessStatus(bool accessGranted)
{
if (!accessGranted)
{
MainThread.BeginInvokeOnMainThread(async () =>
{
await NavigationHelper.Current.CloseModalAsync();
});
}
metadataOutput = new AVCaptureMetadataOutput();
var metadataDelegate = new MetadataOutputDelegate();
metadataOutput.SetDelegate(metadataDelegate, DispatchQueue.MainQueue);
session = new AVCaptureSession();
camera = AVCaptureDevice.DevicesWithMediaType(AVMediaType.Video).First();
input = AVCaptureDeviceInput.FromDevice(camera);
session.AddInput(input);
session.AddOutput(metadataOutput);
metadataOutput.MetadataObjectTypes = AVMetadataObjectType.QRCode | AVMetadataObjectType.EAN8Code | AVMetadataObjectType.EAN13Code;
metadataDelegate.MetadataFound += MetadataDelegate_MetadataFound;
camera.LockForConfiguration(out var error);
camera.VideoZoomFactor = 2;
camera.UnlockForConfiguration();
layer = new AVCaptureVideoPreviewLayer(session);
layer.VideoGravity = AVLayerVideoGravity.ResizeAspectFill;
layer.MasksToBounds = true;
layer.Frame = UIApplication.SharedApplication.KeyWindow.RootViewController.View.Bounds;
view.Layer.AddSublayer(layer);
session.StartRunning();
}
protected override void OnAppearing()
{
base.OnAppearing();
var status = AVCaptureDevice.GetAuthorizationStatus(AVMediaType.Video);
if (status != AVAuthorizationStatus.Authorized)
{
MainThread.BeginInvokeOnMainThread(() =>
{
AVCaptureDevice.RequestAccessForMediaType(AVMediaType.Video, HandleAVRequestAccessStatus);
});
return;
}
HandleAVRequestAccessStatus(true);
}
protected override void OnDisappearing()
{
base.OnDisappearing();
session.StopRunning();
session.RemoveInput(input);
session = null;
}
void Handle_Clicked(object sender, System.EventArgs e)
{
NavigationHelper.Current.CloseModalAsync();
}
void MetadataDelegate_MetadataFound(object sender, AVMetadataMachineReadableCodeObject e)
{
if (resultFound)
{
return;
}
resultFound = true;
var text = e.StringValue;
Device.BeginInvokeOnMainThread(async () =>
{
Vibration.Vibrate(100);
await NavigationHelper.Current.CloseModalAsync();
TinyPubSub.Publish(NavigationParameter.ToString(), text);
});
}
}
public class MetadataOutputDelegate : AVCaptureMetadataOutputObjectsDelegate
{
public override void DidOutputMetadataObjects(AVCaptureMetadataOutput captureOutput, AVMetadataObject[] metadataObjects, AVCaptureConnection connection)
{
foreach (var m in metadataObjects)
{
if (m is AVMetadataMachineReadableCodeObject)
{
MetadataFound(this, m as AVMetadataMachineReadableCodeObject);
}
}
}
public event EventHandler<AVMetadataMachineReadableCodeObject> MetadataFound = delegate { };
}
I'm using Xamarin forms and writing a dependency service for the following objectives :
Open iOS files app. (UIDocumentPickerViewController )
Select any kind of a document.
Copy that document into my application Documents directory. (For app access)
Show that document into my application by storing its path into my SQLite DB.
What I am trying to do here is call the Files app from my application on an Entry click and the click event seems to be working well my dependency service calls perfectly but now when I try to use the UIDocumentPickerViewController I am unable to get View controller context in my dependency service to call the PresentViewController method. Now I know about the xamarin forms context but I don't know if it will work here and I don't even know if it would be a smart idea to use it as it has already been marked as obsolete and since I am not from the iOS background, I don't know what would be the right solution for it.
My code is as follows :
public class DocumentPickerRenderer : IDocumentPicker
{
public object PickFile()
{
var docPicker = new UIDocumentPickerViewController(new string[] { UTType.Data, UTType.Content }, UIDocumentPickerMode.Import);
docPicker.WasCancelled += (sender, wasCancelledArgs) =>
{
};
docPicker.DidPickDocumentAtUrls += (object sender, UIDocumentPickedAtUrlsEventArgs e) =>
{
Console.WriteLine("url = {0}", e.Urls[0].AbsoluteString);
//bool success = await MoveFileToApp(didPickDocArgs.Url);
var success = true;
string filename = e.Urls[0].LastPathComponent;
string msg = success ? string.Format("Successfully imported file '{0}'", filename) : string.Format("Failed to import file '{0}'", filename);
var alertController = UIAlertController.Create("import", msg, UIAlertControllerStyle.Alert);
var okButton = UIAlertAction.Create("OK", UIAlertActionStyle.Default, (obj) =>
{
alertController.DismissViewController(true, null);
});
alertController.AddAction(okButton);
PresentViewController(alertController, true, null);
};
PresentViewController(docPicker, true, null);
}
}
My questions:
Is my methodology correct for picking files?
what will be the object that I will be getting as a callback from a file selection and how will I get the callback?
Is there any other way or something available for xamarin forms, some guide or something that allows me to pick documents from my native file systems and gives a brief on how to handle it in both ios and android?
Hello Guys, You can use following code for picking any type of documents to mention in code using iOS Devices-
use follwing interface:
public interface IMedia
{
Task<string> OpenDocument();
}
public Task<string> OpenDocument()
{
var task = new TaskCompletionSource<string>();
try
{
OpenDoc(GetController(), (obj) =>
{
if (obj == null)
{
task.SetResult(null);
return;
}
var aa = obj.AbsoluteUrl;
task.SetResult(aa.Path);
});
}
catch (Exception ex)
{
task.SetException(ex);
}
return task.Task;
}
static Action<NSUrl> _callbackDoc;
public static void OpenDoc(UIViewController parent, Action<NSUrl> callback)
{
_callbackDoc = callback;
var version = UIDevice.CurrentDevice.SystemVersion;
int verNum = 0;
Int32.TryParse(version.Substring(0, 2), out verNum);
var allowedUTIs = new string[]
{
UTType.UTF8PlainText,
UTType.PlainText,
UTType.RTF,
UTType.PNG,
UTType.Text,
UTType.PDF,
UTType.Image,
UTType.Spreadsheet,
"com.microsoft.word.doc",
"org.openxmlformats.wordprocessingml.document",
"com.microsoft.powerpoint.ppt",
"org.openxmlformats.spreadsheetml.sheet",
"org.openxmlformats.presentationml.presentation",
"com.microsoft.excel.xls",
};
// Display the picker
var pickerMenu = new UIDocumentMenuViewController(allowedUTIs, UIDocumentPickerMode.Import);
pickerMenu.DidPickDocumentPicker += (sender, args) =>
{
if (verNum < 11)
{
args.DocumentPicker.DidPickDocument += (sndr, pArgs) =>
{
UIApplication.SharedApplication.OpenUrl(pArgs.Url);
pArgs.Url.StopAccessingSecurityScopedResource();
var cb = _callbackDoc;
_callbackDoc = null;
pickerMenu.DismissModalViewController(true);
cb(pArgs.Url.AbsoluteUrl);
};
}
else
{
args.DocumentPicker.DidPickDocumentAtUrls += (sndr, pArgs) =>
{
UIApplication.SharedApplication.OpenUrl(pArgs.Urls[0]);
pArgs.Urls[0].StopAccessingSecurityScopedResource();
var cb = _callbackDoc;
_callbackDoc = null;
pickerMenu.DismissModalViewController(true);
cb(pArgs.Urls[0].AbsoluteUrl);
};
}
// Display the document picker
parent.PresentViewController(args.DocumentPicker, true, null);
};
pickerMenu.ModalPresentationStyle = UIModalPresentationStyle.Popover;
parent.PresentViewController(pickerMenu, true, null);
UIPopoverPresentationController presentationPopover = pickerMenu.PopoverPresentationController;
if (presentationPopover != null)
{
presentationPopover.SourceView = parent.View;
presentationPopover.PermittedArrowDirections = UIPopoverArrowDirection.Down;
}
}
Now you need to call using following code:
var filePath = await DependencyService.Get<IMedia>().OpenDocument();
For pick document in Android, you can use following code
public class IntentHelper
{
public const int DocPicker = 101;
static Action<string> _callback;
public static async void ActivityResult(int requestCode, Result resultCode, Intent data)
{ if (requestCode == RequestCodes.DocPicker)
{
if (data.Data == null)
{
_callback(null);
}
else
{
var destFilePath = FilePath.GetPath(CurrentActivity, data.Data);
_callback(destFilePath);
}
}
}
public static Activity CurrentActivity
{
get
{
return (Xamarin.Forms.Forms.Context as MainActivity);
}
}
public static void OpenDocPicker(Action<string> callback)
{
_callback = callback;
var intent = new Intent(Intent.ActionOpenDocument);
intent.AddCategory(Intent.CategoryOpenable);
intent.SetType("*/*");
CurrentActivity.StartActivityForResult(intent, RequestCodes.DocPicker);
}
}
For pick document in Android, you can use following code:
public class IntentHelper
{
public const int DocPicker = 101;
static Action<string> _callback;
public static async void ActivityResult(int requestCode, Result resultCode, Intent data)
{
if (requestCode == RequestCodes.DocPicker)
{
if (data.Data == null)
{
_callback(null);
}
else
{
var destFilePath = FilePath.GetPath(CurrentActivity, data.Data);
_callback(destFilePath);
}
}
}
public static Activity CurrentActivity
{
get
{
return (Xamarin.Forms.Forms.Context as MainActivity);
}
}
public static void OpenDocPicker(Action<string> callback)
{
_callback = callback;
var intent = new Intent(Intent.ActionOpenDocument);
intent.AddCategory(Intent.CategoryOpenable);
intent.SetType("*/*");
CurrentActivity.StartActivityForResult(intent, RequestCodes.DocPicker);
}
}
Use below code to access the helper class: public class Media:
IMedia {
public Task<string> OpenDocument() {
var task = new TaskCompletionSource<string>();
try {
IntentHelper.OpenDocPicker((path) => { task.SetResult(path); });
} catch (Exception ex) {
task.SetResult(null);
}
return task.Task;
}
}
Since I was looking for UIDocumentPickerViewController and not UIDocumentMenuViewController the other answer was not what I was looking for :
So this is how I ended up doing it:
Calling the document picker:
var docPicker = new UIDocumentPickerViewController(new string[]
{ UTType.Data, UTType.Content }, UIDocumentPickerMode.Import);
docPicker.WasCancelled += DocPicker_WasCancelled;
docPicker.DidPickDocumentAtUrls += DocPicker_DidPickDocumentAtUrls;
docPicker.DidPickDocument += DocPicker_DidPickDocument;
var _currentViewController = GetCurrentUIController();
if (_currentViewController != null)
_currentViewController.PresentViewController(docPicker, true, null);
Where GetCurrentUIController is the function to get the current UI controller something like this :
public UIViewController GetCurrentUIController()
{
UIViewController viewController;
var window = UIApplication.SharedApplication.KeyWindow;
if (window == null)
{
return null;
}
if (window.RootViewController.PresentedViewController == null)
{
window = UIApplication.SharedApplication.Windows
.First(i => i.RootViewController != null &&
i.RootViewController.GetType().FullName
.Contains(typeof(Xamarin.Forms.Platform.iOS.Platform).FullName));
}
viewController = window.RootViewController;
while (viewController.PresentedViewController != null)
{
viewController = viewController.PresentedViewController;
}
return viewController;
}
For below iOS 11 i added the DidPickDocument event:
private void DocPicker_DidPickDocument(object sender, UIDocumentPickedEventArgs e)
{
try
{
NSUrl filePath = e.Url.AbsoluteUrl;
//This is the url for your document and you can use it as you please.
}
catch (Exception ex)
{
}
}
For above iOS 11 you use the DidPickDocumentUrls since multipick is supported there :
private void DocPicker_DidPickDocumentAtUrls(object sender, UIDocumentPickedAtUrlsEventArgs e)
{
try
{
List<NSUrl> filePath = e.Urls.ToList().Select(y => y.AbsoluteUrl).ToList();
//returns the list of images selected
}
catch (Exception ex)
{
AppLogger.LogException(ex);
}
}
In rx you can write :
var oe = Observable.FromEventPattern<SqlNotificationEventArgs>(sqlDep, "OnChange");
and then subscribe to the observable to convert the OnChange event on the sqlDep object into an observable.
Similarily, how can you create a Task from a C# event using the Task Parallel Library ?
EDIT: clarification
The solution pointed by Drew and then written explicitely by user375487 works for a single event. As soon as the task finished ... well it is finished.
The observable event is able to trigger again at any time. It is can be seen as an observable stream. A kind of ISourceBlock in the TPL Dataflow. But in the doc http://msdn.microsoft.com/en-us/library/hh228603(v=vs.110).aspx there is no example of ISourceBlock.
I eventually found a forum post explaining how to do that: http://social.msdn.microsoft.com/Forums/en/tpldataflow/thread/a10c4cb6-868e-41c5-b8cf-d122b514db0e
public static ISourceBlock CreateSourceBlock(
Action,Action,Action,ISourceBlock> executor)
{
var bb = new BufferBlock();
executor(t => bb.Post(t), () => bb.Complete(), e => bb.Fault(e), bb);
return bb;
}
//Remark the async delegate which defers the subscription to the hot source.
var sourceBlock = CreateSourceBlock<SomeArgs>(async (post, complete, fault, bb) =>
{
var eventHandlerToSource = (s,args) => post(args);
publisher.OnEvent += eventHandlerToSource;
bb.Complete.ContinueWith(_ => publisher.OnEvent -= eventHandlerToSource);
});
I've not tryed the above code. There may be a mismatch between the async delegate and the definition of CreateSourceBlock.
There is no direct equivalent for the Event Asynchronous Pattern (EAP) baked into the TPL. What you need to do is using a TaskCompletionSource<T> that you signal yourself in the event handler. Check out this section on MSDN for an example of what that would look like which uses WebClient::DownloadStringAsync to demonstrate the pattern.
You can use TaskCompletionSource.
public static class TaskFromEvent
{
public static Task<TArgs> Create<TArgs>(object obj, string eventName)
where TArgs : EventArgs
{
var completionSource = new TaskCompletionSource<TArgs>();
EventHandler<TArgs> handler = null;
handler = new EventHandler<TArgs>((sender, args) =>
{
completionSource.SetResult(args);
obj.GetType().GetEvent(eventName).RemoveEventHandler(obj, handler);
});
obj.GetType().GetEvent(eventName).AddEventHandler(obj, handler);
return completionSource.Task;
}
}
Example usage:
public class Publisher
{
public event EventHandler<EventArgs> Event;
public void FireEvent()
{
if (this.Event != null)
Event(this, new EventArgs());
}
}
class Program
{
static void Main(string[] args)
{
Publisher publisher = new Publisher();
var task = TaskFromEvent.Create<EventArgs>(publisher, "Event").ContinueWith(e => Console.WriteLine("The event has fired."));
publisher.FireEvent();
Console.ReadKey();
}
}
EDIT Based on your clarification, here is an example of how to achieve your goal with TPL DataFlow.
public class EventSource
{
public static ISourceBlock<TArgs> Create<TArgs>(object obj, string eventName)
where TArgs : EventArgs
{
BufferBlock<TArgs> buffer = new BufferBlock<TArgs>();
EventHandler<TArgs> handler = null;
handler = new EventHandler<TArgs>((sender, args) =>
{
buffer.Post(args);
});
buffer.Completion.ContinueWith(c =>
{
Console.WriteLine("Unsubscribed from event");
obj.GetType().GetEvent(eventName).RemoveEventHandler(obj, handler);
});
obj.GetType().GetEvent(eventName).AddEventHandler(obj, handler);
return buffer;
}
}
public class Publisher
{
public event EventHandler<EventArgs> Event;
public void FireEvent()
{
if (this.Event != null)
Event(this, new EventArgs());
}
}
class Program
{
static void Main(string[] args)
{
var publisher = new Publisher();
var source = EventSource.Create<EventArgs>(publisher, "Event");
source.LinkTo(new ActionBlock<EventArgs>(e => Console.WriteLine("New event!")));
Console.WriteLine("Type 'q' to exit");
char key = (char)0;
while (true)
{
key = Console.ReadKey().KeyChar;
Console.WriteLine();
if (key == 'q') break;
publisher.FireEvent();
}
source.Complete();
Console.ReadKey();
}
}