I am using Xam.Connectivity plugin for checking Internet Connectivity.
Here is my code
if (!CrossConnectivity.Current.IsConnected)
{
DependencyService.Get<ISQLite>().ShowSnackBar("No Internet Connection");
}
If I need to check internet every second then I am calling this code every second using Device Timer.This code is good,but I want to detect when Internet goes down with out using any Timer.
So how to achieve this?
I think you would be better off to use the event that is implemented for this.
CrossConnectivity.Current.ConnectivityChanged += async (sender, args) =>
{
if (!args.IsConnected)
DependencyService.Get<ISQLite>().ShowSnackBar("No Internet Connection");
};
Whenever the connection state now changes, you will be notified automatically.
Please note that you are using the "old" plugin. This functionality is now also captured in the Xamarin.Essentials library which works similar, but will probably be the maintained version from now.
Related
We are evaluating FiddlerCore for a use-case. Basically, for now we just want to catch all of the endpoints/urls being requested on a system. This works fine in Fiddler, no issues. But we only want to catch them while a certain vendor software is open. So we want to write a plugin to that software that will run when it launches, and then exit when it exits. Hence, using FiddlerCore (hopefully).
As proof-of-concept, I just made a simple app, one form with a textbox, that it should just append each url into the textbox. Simple as simple can be. However, it's not doing anything. I run the app, then refresh a page in my browser, and ... nothing.
Here is the entire (non-generated) code of my program...
using Fiddler;
using System;
using System.Windows.Forms;
namespace ScratchCSharp {
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
FiddlerApplication.AfterSessionComplete += FiddlerApplication_AfterSessionComplete;
FiddlerApplication.Startup(8888, FiddlerCoreStartupFlags.Default);
}
private void FiddlerApplication_AfterSessionComplete(Session s) {
textBox1.Invoke((Action)delegate () {
AddText(s.fullUrl);
});
}
public void AddText(string text) {
textBox1.Text += $"{text}\n";
}
}
}
After a little more poking around, I see that FiddlerApplication.IsSystemProxy is returning false. Seems to have to do with that the Startup flag to set as system proxy is no longer honored, and it tells you now to use the Telerik.NetworkConnections.NetworkConnectionManager to set it as the system proxy. But I can't find anywhere that actually says how to do that. The closest thing I could find is this thread which seems to be their official answer to this question. However, it only goes into a lot of talk about WHY they deprecated the flag, and what their thinking was in how they designed its replacement, but not actually into HOW TO USE the replacement. The Demo app also does NOT use these libraries (probably why it doesn't catch anything either).
The biggest problem though, is that the NetworkConnectionsManager class has no public constructor, so you can't create an instance. It is not inheritable, so you can't make a subclass instance. All of the methods on it are instance methods, not static/shared. And there seems to be no method in the libraries which will create an instance of NetworkConnectitonsManager for you.
So while the class is clearly designed to be used as an instance (hence the methods not being static/shared, there doesn't actually seem to be any way to create an instance.
Any help on how to set this thing up to catch all the outgoing URLs on the system?
You can use the following code for starting Fiddler Core and registering it as a system proxy:
FiddlerCoreStartupSettings startupSettings =
new FiddlerCoreStartupSettingsBuilder()
.ListenOnPort(fiddlerCoreListenPort)
.RegisterAsSystemProxy()
.ChainToUpstreamGateway()
.DecryptSSL()
.OptimizeThreadPool()
.Build();
FiddlerApplication.Startup(startupSettings);
Some of the methods are obsolete for now, but I would recommend to stick with them until the NetworkConnectionManager API is improved and finalized.
Also, there is a sample application (that FiddlerCore installer installs on the Desktop), which is useful for a starting point with the development.
I am building Xamarin.Forms app that pretty much works offline except a few calls to a web-service. Now I need to check internet connection just before I make a request, but I cannot find a solution or an answer that would allow checking internet connection only once not continuously
You could use Xamarin.Essentials and specifically Connectivity class as CrossConnectivity features have been consolidated into Xamarin.Essentials toolkit.
var connect = Connectivity.NetworkAccess;
if (connect != NetworkAccess.Internet) Message = "Device does not have internet access.";
else { // api call }
You can use the ConnectivityPlugin by James Montemagno
Nuget can be found here
For check the internet you just have to do this:
if(CrossConnectivity.Current.IsConnected)
{
//You are connected to the internet!!!
}
You might wanna check this: https://jamesmontemagno.github.io/ConnectivityPlugin/CheckingConnectivity.html
Xamarin Essentials Connectivity is also an option.
if (Connectivity.NetworkAccess == NetworkAccess.Internet)
{
//You are connected to the internet!!!
}
I can not find how to start WPS client in Windows 10 from command prompt or powershell. When I used Linux, everything was really ease with wla_supplicant (wpa_cli wps_pbc). Is there something similar in Windows?
Does anyone know how to set up Wi-Fi network (over WPS) key without human input in Windows?
I also tried WCN (Windows Connect Now) from Microsoft as it implements WPS features. I got also samples from Windows SDK on WCN, but they could not get key by WPS (it faild). But if I use Windows user interface to connect wiothout PIN, everyting seems to be pretty fine.
I am sure that there is possibility to do that, it is very important to perform Wifi Protected Setup by button start from the command prompt or app (C++/C#) without human intrusion or input (once WPS is on air, Windows should automatically get the network key and connect then).
I don't know if it's too late to answer, just put what I know in here and hope it can help.
First, if your system has updated to 16299(Fall Creator Update), you can just simply use new wifi api from UWP.
Install newest Windows SDK, create a C# console project, target C# version to at least 7.1, then add two reference to the project.
C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETCore\v4.5\System.Runtime.WindowsRuntime.dll
C:\Program Files (x86)\Windows Kits\10\UnionMetadata\10.0.16299.0\Windows.winmd
After all of that , code in below should work.
using System;
using System.Threading.Tasks;
using Windows.Devices.Enumeration;
using Windows.Devices.WiFi;
class Program
{
static async Task Main(string[] args)
{
var dic = await DeviceInformation.FindAllAsync(WiFiAdapter.GetDeviceSelector());
if (dic.Count > 0)
{
var adapter = await WiFiAdapter.FromIdAsync(dic[0].Id);
foreach (var an in adapter.NetworkReport.AvailableNetworks)
{
if (an.Ssid == "Ssid which you want to connect to.")
{
// Fouth parameter which is ssid can not be set to null even if we provided
// first one, or an exception will be thrown.
await adapter.ConnectAsync(an, WiFiReconnectionKind.Manual, null, "",
WiFiConnectionMethod.WpsPushButton);
}
}
}
}
}
Build and run the exe, then push your router's button, your pc will be connect to the router.
But if you can not update to 16299, WCN will be your only choice. You may already notice that if call IWCNDevic::Connect frist with push-button method, the WSC(Wifi Simple Configuration) session will fail. That's because WNC would not start a push-button session as a enrollee, but only as a registrar. That means you have to ensure that router's button has been pushed before you call IWCNDevic::Connect. The way to do that is using Native Wifi api to scan your router repeatedly, analyse the newest WSC information element from the scan result, confirm that Selected Registrar attribute has been set to true and Device Password Id attribute has been set to 4. After that, query the IWCNDevice and call Connect function will succeed. Then you can call IWCNDevice::GetNetworkProfile to get a profile that can use to connect to the router. Because it's too much of code, I will only list the main wifi api that will be used.
WlanEnuminterfaces: Use to get a available wifi interface.
WlanRegisterNotification: Use to register a callback to handle scan an connect results.
WlanScan: Use to scan a specified wifi BSS.
WlanGetNetworkBsslist: Use to get newest BSS information after scan.
WlanSetProfile: Use to save profile for a BSS.
WlanConnect: Use to connect to a BSS.
And about the WSC information element and it's attributes, you can find all the information from Wi-Fi Simple Configuration Technical Specification v2.0.5.
For Krisz. About timeout.
You can't cast IAsyncOperation to Task directly. The right way to do that is using AsTask method. And also, you should cancel ConnectAsync after timeout.
Sample code:
var t = adapter.ConnectAsync(an, WiFiReconnectionKind.Manual, null, "",
WiFiConnectionMethod.WpsPushButton).AsTask();
if (!t.Wait(10000))
t.AsAsyncOperation().Cancel();
I have a SignalR hub and two clients (Windows and PCL for Android and iOS). Neither of the clients is able to call some methods on the server. This behaviour is quite odd, since the methods look very similar. Moreover, a colleague of mine is able to call methods I cannot call, and vice versa, does not invoke methods that I invoke with no problems.
Here is an example of a method, which works for me and does not work for my colleague:
public override async Task<bool> RefreshArray(User user, int waitMilis)
{
var cts = new CancellationTokenSource();
try
{
cts.CancelAfter(waitMilis);
await Proxy.Invoke("RefreshArray", user);
return true;
}
catch (Exception ex)
{
OnExceptionOccured(ex);
return false;
}
}
And a method which does not work for me, but works for my colleague:
public override async Task<bool> RequestInformation(User user, Product product, int waitMilis)
{
var cts = new CancellationTokenSource();
try
{
cts.CancelAfter(waitMilis);
await Proxy.Invoke("RequestInformation", user, product);
return true;
}
catch (Exception ex)
{
OnExceptionOccured(ex);
return false;
}
}
Yes, me and my colleague have exactly the same code. And no, there are no typos or different arguments. I have tried to get as much data from the client connection as possible, by setting _connection.TraceLevel = TraceLevels.All; However, I did not get any information on the invoked methods, just on the replies from the hub. When calling RefreshArray, I got exactly the data I requested. When calling RequestInformation, the debugger never even hit the breakpoint in the hub method and the _connection.Trace displayed only this: 11:22:45.6169660 - 7bc57897-489b-49a2-8459-3fcdb8fcf974 - SSE: OnMessage(Data: {})
Has anybody solved a similar issue? Is there a solution?
UPDATE 1
I just realized that I have encountered almost the same issue about a year ago (Possible SignalR bug in Xamarin Android). StackOverflow has also pointed me to a question with almost the same issue (SignalR on Xamarin.iOS - randomly not able to call Hub method), just related to iOS and Azure. However, I got the same proble even outside Xamarin, on Windows Phone 8.1 and and Windows 10 Universal App. Moreover, I am running the server just locally, so it is not an issue od Azure. Is it really possible, that a 2 years old bug has no solution?
UPDATE 2
I have just created a simple console application with SignalR.Client. In the console application every method worked just fine. Amazingly, also the Windows 10 Universal Application started to behave as expected - every hub method was invoked correctly. Windows Phone 8.1 also improved its behaviour (all hub methods invoked). However, every now and then the connection tried to reconnect periodically (for no apparent reason), leading to Connection started reconnecting before invocation result was received. error. The Android application still behaved as before.
So I tried to replicate my previous steps and created another console application, but this time with SignalR.Client.Portable library. To my dissapointment, there was no change in the Android application behaviour.
Next week we will start to test our application on iOS, so I really wonder what new oddities will we encounter.
I have managed to solve the problem (at least so it seems). As it turned out, there is some weird stuff going around, when an application receives an answer from SignalR hub. It seems as if the HubProxy was blocked for a certain period of time on Android, while it drops the connection and starts to reconnect periodically on Windows Phone, not waiting for an asnwer from the hub.
The implementation of RefreshArray on the hub was something like this:
public async Task RefreshArray(User user)
{
await Clients.Caller.SendArray(_globalArray);
await Clients.Caller.SendMoreInformation(_additionalInfo);
}
Because the method sent two methods as an answer, the client Proxy got stuck and each platform handled it in its own unexpected way. The reason why some methods were called on my computer and not on colleagues was, simply, because we had different position of breakpoints, which enabled the application to resolve at least some requests and responses.
The ultimate solution was to add some synchronization into the invokation of methods. Now my hub calls only await Clients.Caller.SendArray(_globalArray);. This is then handled on the client with a ArraySent(string[] array) event, which then subsequently invokes the SendMoreInformation() method on the hub.
I downloaded the red5-recorder (http://www.red5-recorder.com/) , which fails to allow me to start recording. After debugging I found that the netconnection, needed to record to a media server, created does not fire a NetStatusEvent event, so essentially it fails silently. I have implemented the connection with the following minimal working example:
trace("make net connection");
nc = new NetConnection();
nc.client = { onBWDone: function():void{ trace("bandwidth check done.") } };
trace("add event listener");
nc.addEventListener(NetStatusEvent.NET_STATUS, function(event:NetStatusEvent) {
trace("handle");
});
trace("connect!");
nc.connect("rtmp://localshost/oflaDemo/test/");
trace("connect done");
The output of this piece of code is:
make net connection
add event listener
connect!
connect done
The actionscript api states that the connect-call always fires such an event:
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/net/NetConnection.html#includeExamplesSummary
Moreover, the netconnection is not 'connected' (a state of the NetConnection object) 10 seconds after the call. I also took a look at this: NetConnect fails silently in Flash when called from SilverLight But the fix suggested by the author, swapping rtmp and http in the connection uri, do not work. Also, I tested the uri and in fact the exact same code sniplet in a personal project, where it did work. I just can not seem to find why connecting to a media server fails silently in the red5-recorder project.
The awkward part is that if I pass some random string as a conenction uri, still nothing happens (no event, no exception, no crash). Also not setting nc.client becore nc.connect(), which caused exceptions in my experience, did not cause exceptions.
Any suggestions are welcome.
You are setting the address to localshost instead localhost.
nc.connect("rtmp://localshost/oflaDemo/test/");
Correct address:
nc.connect("rtmp://localhost/oflaDemo/test/");