Develop Reference

Using C# & Xamarin Forms - How can I close one modal without setting of chain of closures

In one stage of my app (Android & iOS are the ones we care about) we've got three pages which take in details and then open a webView for the user to input their card details to take a payment - this can't be done in the app due to Apple's guidelines.
I need to format the navigation in a way that when the user has finished in the webView it closes and then closes the 3 previous modals to get back to the original page. I've got it all working with the Appearing event so each page just closes itself:
this.Appearing += async (s, e) =>
{
await Navigation.PopModalAsync();
};
The issue I'm now having is that when the user presses the back button on the phone, it closes all of the pages that they've been through already & back to the original. I thought about implementing a custom nav bar and disabling the back button on the hardware but this would cause the same problem with the Appearing event.
Is there any easy way to solve this?
EDIT: Relevant code;
async void OnButtonClicked(object sender, EventArgs eventArgs)
{
if (IsConnected)
{
ActivityIndicator.IsVisible = true;
var button = (Button) sender;
button .IsEnabled = false;
await Navigation.PushModalAsync(new Page());
this.Appearing += (s, e) =>
{
ActivityIndicator.IsVisible = false;
button.IsEnabled = true;
RefreshPage();
};
}
else
{
NoInternetLabel.IsVisible = true;
}
}

Use this:
YourButton.Clicked += OpenPage;
OpenPage looks like this:
async public void OpenPage(object sender, EventArgs args)
{
await Navigation.PushAsync(new PageToShow());
}
You don't have to do anything to handle the PageToShow() closing, that happens by itself when the user presses the back button.

Managed to solve this by using Actions. In each new Page() we passed up an async method to close it once the one after had completed;
var nextPage = new Page(async () =>
{
await Navigation.PopModalAsync();
_completedSuccessfully();
});
await Navigation.PushModalAsync(nextPage);
And in the new page class;
private readonly Action _completedSuccessfully;
public Page(Action completedSuccessfully)
{
_completedSuccessfully = completedSuccessfully;
}
This meant that when the webView closed it called the completedSuccessfully() action and then chained all of them to the original page.

WebBrowser.Document is null on return from thread, not updating in new thread

public static User registerUser()
{
Uri test = new Uri("https://www.example.com/signup");
HtmlDocument testdoc = runBrowserThread(test);
string tosend = "test";
User user = new User();
user.apikey = tosend;
return user;
}
public static HtmlDocument runBrowserThread(Uri url)
{
HtmlDocument value = null;
var th = new Thread(() =>
{
var br = new WebBrowser();
br.DocumentCompleted += browser_DocumentCompleted;
br.Navigate(url);
value = br.Document;
Application.Run();
});
th.SetApartmentState(ApartmentState.STA);
th.Start();
th.Join(8000);
return value;
}
static void browser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
var br = sender as WebBrowser;
if (br.Url == e.Url)
{
Console.WriteLine("Natigated to {0}", e.Url);
Console.WriteLine(br.Document.Body.InnerHtml);
System.Console.ReadLine();
Application.ExitThread(); // Stops the thread
}
}
I am trying to scan this page, and while it does get the HTML it does not pass it back in to the function call, but instead sends back null (I presume that is post processing).
How can I make it so that the new thread passes back its result?

There are several problems with your approach.
You're not waiting till the webpage is navigated, I mean till Navigated event. So document could be null till then.
You're quitting after 8 seconds, if page takes more than 8 seconds to load you won't get the document.
If document isn't properly loaded, you're leaving the thread alive.
I guess WebBrowser control will not work as expected unless you add it into a form and show it(it needs to be visible in screen).
Etc..
Don't mix up things. Your goal can't be to use WebBrowser. If you need to just download the string from webpage, use HttpClient.GetStringAsync.
Once you get the page as string format, If you want to manipulate the html, use HtmlAgilityPack.

Moved over to using WaitN instead of the default browser model. A bit buggy but now works like it should do.
using (var browser = new FireFox("https://www.example.com/signup"))
{
browser.GoTo("https://example.com/signup");
browser.WaitForComplete();
}

CustomMessageBox from Windows Phone 8 Toolkit throw NullPointerException

Code for creating the CustomMessageBox:
CustomMessageBox is a property, and not a reference to the C# Class in the Toolkit.
CustomMessageBox.Dismissed += (dismissSender, dismissedEvent) =>
{
switch (dismissedEvent.Result)
{
case CustomMessageBoxResult.LeftButton:
PlaceCall(clickedFavorite.Name, clickedFavorite.PhoneNo);
break;
case CustomMessageBoxResult.RightButton:
HERE ---> SendText(clickedFavorite.PhoneNo);
break;
}
};
Code for SendText() method:
private void SendText(String phoneNo)
{
var smsTask = new SmsComposeTask
{
To = phoneNo
};
smsTask.Show();
}
Thing is when the SmsComposeTask has started, the Phone navigates to the SMS application, which is correct.
If the user then decides to go back, with the Hardware Back Button, the SMS application closes and the phone shows my app again - but immediately closes, caused by a NullPointerException:
at Microsoft.Phone.Controls.CustomMessageBox.ClosePopup(Boolean restoreOriginalValues)
at Microsoft.Phone.Controls.CustomMessageBox.<>c__DisplayClass4.<Dismiss>b__1(Object s, EventArgs e)
at Microsoft.Phone.Controls.Transition.OnCompleted(Object sender, EventArgs e)
at MS.Internal.CoreInvokeHandler.InvokeEventHandler(Int32 typeIndex, Delegate handlerDelegate, Object sender, Object args)
at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName)
I have also tried to override the OnBackKeyPress event, like this:
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
if (CustomMessageBox != null && CustomMessageBox.IsEnabled)
{
e.Cancel = true;
}
else
{
base.OnBackKeyPress(e);
}
}
Does anyone know what to do?

I have found a solution to my own problem. Instead of using the faulty CustomMessageBox, I found Coding4Fun Windows Phone Toolkit which provides a by far, more stable message box called MessagePrompt - here's how to use it.
Create buttons
var smsButton = new Button { Content = "SMS" };
smsButton.Click += (o, args) =>
{
// do something
};
var buttonList = new List<Button>
{
smsButton
};
Create the actual message prompt
var msgPrompt = new MessagePrompt
{
Title = "Message Prompt Title",
Body = new TextBlock { Text = "Text for the Body", FontSize = 25, TextWrapping = TextWrapping.Wrap },
ActionPopUpButtons = buttonList
};
Show it
msgPrompt.Show()
No bullocks
The good thing, which I have experienced with this MessagePrompt is that you are not bound to two static Left and Right buttons like with CustomMessageBox.
And if you want, you can set the Body property to a whole new XAML page, which makes this control flexible.
Reference: Coding4Fun WP7 Message Prompt in depth

Doesn't this problem has something to do with Windows Phone Application lifecycle. As can be found here, figure 6. When activiting another program when your program is active you should save all application data so when a reactivating event ,such as navigating with your back button back to your application, starts your program again you can load the user's data again.

I'm not sure what's happening, but you can just delay the SMS task to avoid the issue:
CustomMessageBox.Dismissed += (dismissSender, dismissedEvent) =>
{
switch (dismissedEvent.Result)
{
case CustomMessageBoxResult.LeftButton:
PlaceCall(clickedFavorite.Name, clickedFavorite.PhoneNo);
break;
case CustomMessageBoxResult.RightButton:
Dispatcher.BeginInvoke(new Action(() => SendText(clickedFavorite.PhoneNo)));
break;
}
};

My 0.02$: this is a bug in the CustomMessageBox. They're keeping lots of singletons alive there and a good timing bug doesn't do that a world of good. Agreed with KooKiz that you can't work around with that without either fixing CustomMessageBox or waiting until the CustomMessageBox finishes its thing. From my ad-hoc testing it requires anywhere between 2-6 Dispatcher.BeginInvoke() until those actions finish. Instead, maybe consider using DispatcherTimer and wait 256MS which should be enough time.
private void MainPage_Loaded(object sender, RoutedEventArgs e)
{
var msgBox = new CustomMessageBox()
{
Caption = "foo",
Message = "bar",
LeftButtonContent = "baz",
RightButtonContent = "goo",
IsFullScreen = false,
};
msgBox.Dismissed += (s, args) =>
{
DispatcherTimerHelper.InvokeReallySoon(() =>
{
new SmsComposeTask()
{
Body = "foo",
To = "bar"
}.Show();
});
};
msgBox.Show();
}
public static class DispatcherTimerHelper
{
public static void InvokeReallySoon(Action action)
{
var t = new DispatcherTimer() {Interval = TimeSpan.FromMilliseconds(256)};
t.Tick += (s, args) => action();
t.Start();
}
}

The problem just happen in wp8.
I use the same code in wp7, nothing wrong happens.
Use Code4fun messagebox is a good choice，but is Button Click handler you need to call
MessagePrompt.Hide();
to close the MessagePrompt.

used a boolean on the dismissed event to define which button had been pressed. I then implemented the code I would of implemented in the dismissed event in the Unloaded event instead. This seemed to solve the issue.
i.e
messageBox.Dismissed += (s1, e1) =>
{
switch (e1.Result)
{
case CustomMessageBoxResult.LeftButton:
{
delete = true ;
}
break;
case CustomMessageBoxResult.RightButton:
break;
case CustomMessageBoxResult.None:
break;
default:
break;
}
};
messageBox.Unloaded += (s1, e1) =>
{
if (delete)
DeleteWorkout();
};

This is a known bug.
It was fixed in the latest version.
Remove the reference and install the toolkit again.

How to make WebBrowser wait till it loads fully?

I have a C# form with a web browser control on it.
I am trying to visit different websites in a loop.
However, I can not control URL address to load into my form web browser element.
This is the function I am using for navigating through URL addresses:
public String WebNavigateBrowser(String urlString, WebBrowser wb)
{
string data = "";
wb.Navigate(urlString);
while (wb.ReadyState != WebBrowserReadyState.Complete)
{
Application.DoEvents();
}
data = wb.DocumentText;
return data;
}
How can I make my loop wait until it fully loads?
My loop is something like this:
foreach (string urlAddresses in urls)
{
WebNavigateBrowser(urlAddresses, webBrowser1);
// I need to add a code to make webbrowser in Form to wait till it loads
}

Add This to your code:
webBrowser1.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);
Fill in this function
private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) {
//This line is so you only do the event once
if (e.Url != webBrowser1.Url)
return;
//do you actual code
}

After some time of anger of the crappy IE functionality I've came across making something which is the most accurate way to judge page loaded complete.
Never use the WebBrowserDocumentCompletedEventHandler event
use WebBrowserProgressChangedEventHandler with some modifections seen below.
//"ie" is our web browser object
ie.ProgressChanged += new WebBrowserProgressChangedEventHandler(_ie);
private void _ie(object sender, WebBrowserProgressChangedEventArgs e)
{
int max = (int)Math.Max(e.MaximumProgress, e.CurrentProgress);
int min = (int)Math.Min(e.MaximumProgress, e.CurrentProgress);
if (min.Equals(max))
{
//Run your code here when page is actually 100% complete
}
}
Simple genius method of going about this, I found this question googling "How to sleep web browser or put to pause"

According to MSDN (contains sample source) you can use the DocumentCompleted event for that. Additional very helpful information and source that shows how to differentiate between event invocations can be found here.

what you experiencend happened to me . readyStete.complete doesnt work in some cases. here i used bool in document_completed to check state
button1_click(){
//go site1
wb.Navigate("site1.com");
//wait for documentCompleted before continue to execute any further
waitWebBrowserToComplete(wb);
// set some values in html page
wb.Document.GetElementById("input1").SetAttribute("Value", "hello");
// then click submit. (submit does navigation)
wb.Document.GetElementById("formid").InvokeMember("submit");
// then wait for doc complete
waitWebBrowserToComplete(wb);
var processedHtml = wb.Document.GetElementsByTagName("HTML")[0].OuterHtml;
var rawHtml = wb.DocumentText;
}
// helpers
//instead of checking readState . we get state from DocumentCompleted Event via bool value
bool webbrowserDocumentCompleted = false;
public static void waitWebBrowserToComplete(WebBrowser wb)
{
while (!webbrowserDocumentCompleted )
Application.DoEvents();
webbrowserDocumentCompleted = false;
}
form_load(){
wb.DocumentCompleted += (o, e) => {
webbrowserDocumentCompleted = true;
};
}

How to use AxWebBrowser in console application

I wanna use AxWebBrowser on console application, but it give me following exception:
Exception of type 'System.Windows.Forms.AxHost+InvalidActiveXStateException' was thrown.
anybody please help me on this by any sample code for using AxWebBrowser in console application c# without any exeption ...

Yes, the [STAThread] attribute is required on your Main() method so that COM is initialized properly to make the main thread a Single Threaded Apartment. That's not all though, you will also need to pump a message loop. That's a requirement for an STA. Without one, WebBrowser cannot update its state or run its event handlers, you'll never get the DocumentCompleted event for example. You can get a message loop with Application.Run().
Your console application is now indistinguishable from a Windows Forms application. It is actually easier to get everything right by starting a new project with the Windows Forms application project template, then Project + Properties, Output type = Console Application. Edit the Application.Run() call in Program.cs so it doesn't create a form. It won't make dealing with Application.Run() any easier, consider a Timer to run code.

Add the STAThread attribute to your Main method.
However, you should not be using the "raw" ActiveX control.
Instead, add a reference to System.Windows.Forms.dll and use the WebBrowser class. (Yes, you can do that in a Console app)
Also, automating IE is not ideal. You should consider using the WebCLient class.

My class is as below but in the run time it gives me System.Windows.Forms.AxHost+InvalidActiveXStateException:
public class Browse
{
private static AxWebBrowser wBrowser;
public static Result StartBrowse(string url)
{
var validUri = (url.Contains("http://") ? url : "http://" + url);
wBrowser = new AxWebBrowser();
System.Resources.ResourceManager resources = new System.Resources.ResourceManager(typeof(AxWebBrowser));
((ISupportInitialize) (wBrowser)).BeginInit();
wBrowser.OcxState = ((AxHost.State)(resources.GetObject("wBrowser.OcxState")));
wBrowser.NewWindow2 += wBrowser_NewWindow2;
wBrowser.NewWindow3 += wBrowser_NewWindow3;
wBrowser.DocumentComplete += wBrowser_DocumentComplete;
wBrowser.DownloadComplete += wBrowser_DownloadComplete;
if (string.IsNullOrEmpty(html) || validUri != url)
{
object empty = System.Reflection.Missing.Value;
wBrowser.Silent = true;
wBrowser.Navigate(validUri, ref empty, ref empty, ref empty, ref empty);
}
return null;
}
static void wBrowser_DownloadComplete(object sender, EventArgs e)
{
doAlgorithm();
}
static void wBrowser_DocumentComplete(object sender, DWebBrowserEvents2_DocumentCompleteEvent e)
{
doAlgorithm();
}
static void wBrowser_NewWindow3(object sender, DWebBrowserEvents2_NewWindow3Event e)
{
e.cancel = true;
}
static void wBrowser_NewWindow2(object sender, DWebBrowserEvents2_NewWindow2Event e)
{
e.cancel = true;
}
}

First, the thread in which the control is hosted must be in single-threaded apartment, you can either put the STAThread in your Main method, or create a separated Thread like this:
var thread = new Thread(() =>
{
//My code
});
thread.SetApartmentState(ApartmentState.STA);
thread.Start();
thread.Join(); //Wait for thread termination
Second, you must start a message loop:
while (true) //Put some exit condition
System.Windows.Forms.Application.DoEvents();
Third the control must be hosted in a visible form. The form must be visible just once, so to avoid "flickering", you can write this code:
var browser = new AxWebBrowser();
var hostForm = new Form();
//Set form 0 size, without any control box / title / icon
hostForm.Width = 0;
hostForm.Height = 0;
hostForm.ShowInTaskbar = false;
hostForm.ControlBox = false;
hostForm.ShowIcon = false;
hostForm.MinimizeBox = false;
hostForm.MaximizeBox = false;
//Add browser control
hostForm.Controls.Add(browser);
//Show and immediately hide
hostForm.Show();
hostForm.Hide();
Finally you might want to disable the "click" sound (How to disable click sound in WebBrowser Control)
The final code:
class Program
{
[STAThread]
static void Main(string[] args)
{
URLSecurityZoneAPI.InternetSetFeatureEnabled(URLSecurityZoneAPI.InternetFeaturelist.DISABLE_NAVIGATION_SOUNDS, URLSecurityZoneAPI.SetFeatureOn.PROCESS, true);
var browser = new AxWebBrowser();
var hostForm = new Form();
hostForm.Width = 0;
hostForm.Height = 0;
hostForm.ShowInTaskbar = false;
hostForm.ControlBox = false;
hostForm.ShowIcon = false;
hostForm.MinimizeBox = false;
hostForm.MaximizeBox = false;
hostForm.Controls.Add(browser);
hostForm.Show();
hostForm.Hide();
browser.DocumentComplete += delegate(object sender, DWebBrowserEvents2_DocumentCompleteEvent e)
{
var doc = (IHTMLDocument3)browser.Document;
Console.WriteLine(doc.documentElement.innerHTML);
};
browser.Navigate("www.google.com");
while (true)
System.Windows.Forms.Application.DoEvents();
}
}