Bug 41681 - [WP] Page render fails after performing a Bar Code Scan using Zxing Component
Summary: [WP] Page render fails after performing a Bar Code Scan using Zxing Component
Status: RESOLVED NORESPONSE
Alias: None
Product: Forms
Classification: Xamarin
Component: Windows ()
Version: 2.2.0
Hardware: PC Windows
: --- normal
Target Milestone: ---
Assignee: Chris King
URL:
Depends on:
Blocks:
 
Reported: 2016-06-10 07:27 UTC by Anubhav Ranjan
Modified: 2017-06-20 15:23 UTC (History)
4 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:

Notice (2018-05-24): bugzilla.xamarin.com is now in read-only mode.

Please join us on Visual Studio Developer Community and in the Xamarin and Mono organizations on GitHub to continue tracking issues. Bugzilla will remain available for reference in read-only mode. We will continue to work on open Bugzilla bugs, copy them to the new locations as needed for follow-up, and add the new items under Related Links.

Our sincere thanks to everyone who has contributed on this bug tracker over the years. Thanks also for your understanding as we make these adjustments and improvements for the future.


Please create a new report on Developer Community or GitHub with your current version information, steps to reproduce, and relevant error messages or log files if you are hitting an issue that looks similar to this resolved bug and you do not yet see a matching new report.

Related Links:
Status:
RESOLVED NORESPONSE

Description Anubhav Ranjan 2016-06-10 07:27:10 UTC
Once the scanning is performed, the customer is making use PushAsync method to navigate to a different page where the scanned text is to be shown. However, the page appears completely blank.

#Description:
===========
In our application I have one screen where I can scan a barcode, after a successful scan I then navigate to another screen. Upon navigating to this other screen the screen does not render correctly, the app bar is shown, properties are read from the view model but the pivot and other controls are not rendered, therefore rendering an empty screen.

Is there any way I can update the UI after the navigation has occurred?

This is using 1.4.7.1 of the ZXing.Net.Mobile library and version 2.2.0.45 of XF.

Sample:
========
https://dl.dropboxusercontent.com/u/30949500/Xamarin%20Samples/NavigationAfterScanSample.zip

Steps to Reproduce:
=============
- Run the App on Device
- Press the Scan Button
- Scan any BarCode (https://upload.wikimedia.org/wikipedia/commons/5/5d/UPC-A-036000291452.png)
- After scanning, the page is navigated to Page2
Here the screen appears to be blank. Nothing is rendered!


Note: Pressing NoScan just updated the ViewModel with text NoScan. However, this text does render properly.


Version Information:
==============
Microsoft Visual Studio Enterprise 2015
Version 14.0.25123.00 Update 2
Microsoft .NET Framework
Version 4.6.01038

Installed Version: Enterprise

Architecture and Modeling Tools   00322-80000-00000-AA004
Microsoft Architecture and Modeling Tools
    
UML® and Unified Modeling Language™ are trademarks or registered trademarks of the Object Management Group, Inc. in the United States and other countries.

Visual Basic 2015   00322-80000-00000-AA004
Microsoft Visual Basic 2015

Visual C# 2015   00322-80000-00000-AA004
Microsoft Visual C# 2015

Visual C++ 2015   00322-80000-00000-AA004
Microsoft Visual C++ 2015

Windows Phone SDK 8.0 - ENU   00322-80000-00000-AA004
Windows Phone SDK 8.0 - ENU

Application Insights Tools for Visual Studio Package   5.208.60602.2
Application Insights Tools for Visual Studio

ASP.NET and Web Tools 2015.1   14.1.20512.0
ASP.NET and Web Tools 2015.1

ASP.NET Web Frameworks and Tools 2012.2   4.1.41102.0
For additional information, visit http://go.microsoft.com/fwlink/?LinkID=309563

ASP.NET Web Frameworks and Tools 2013   5.2.40314.0
For additional information, visit http://www.asp.net/

Azure App Service Tools v2.8.1   14.0.11123.0
Azure App Service Tools v2.8.1

Common Azure Tools   1.7
Provides common services for use by Azure Mobile Services and Microsoft Azure Tools.

JavaScript Language Service   2.0
JavaScript Language Service

JavaScript Project System   2.0
JavaScript Project System

JetBrains ReSharper Ultimate 10.0.2   Build 104.0.20151218.120627
JetBrains ReSharper Ultimate package for Microsoft Visual Studio. For more information about ReSharper Ultimate, visit http://www.jetbrains.com/resharper. Copyright © 2016 JetBrains, Inc.

Microsoft .NET Core Tools (Preview 1)   14.1.20512.0
Microsoft .NET Core Tools (Preview 1)

Microsoft Azure Mobile Services Tools   1.4
Microsoft Azure Mobile Services Tools

NuGet Package Manager   3.4.4
NuGet Package Manager in Visual Studio. For more information about NuGet, visit http://docs.nuget.org/.

PreEmptive Analytics Visualizer   1.2
Microsoft Visual Studio extension to visualize aggregated summaries from the PreEmptive Analytics product.

SQL Server Data Tools   14.0.60311.1
Microsoft SQL Server Data Tools

TypeScript   1.8.31.0
TypeScript tools for Visual Studio

Visual Studio Tools for Universal Windows Apps   14.0.25219.00
The Visual Studio Tools for Universal Windows apps allow you to build a single universal app experience that can reach every device running Windows 10: phone, tablet, PC, and more. It includes the Microsoft Windows 10 Software Development Kit.

Xamarin   4.2.0.21 (a532c82)
Visual Studio extension to enable development for Xamarin.iOS and Xamarin.Android.

Xamarin.Android   6.1.99.224 (804c6cb)
Visual Studio extension to enable development for Xamarin.Android.

Xamarin.iOS   9.9.0.719 (3afb4af)
Visual Studio extension to enable development for Xamarin.iOS.
Comment 2 John Hardman 2016-06-13 11:21:52 UTC
Anubhav - have you tried using Device.BeginInvokeOnMainThread to ensure that your UI operations are happening on the UI thread?
Comment 3 Chris King 2017-06-20 15:23:14 UTC
We haven't heard back from you so we're going to close this issue for now. But if you're able to reproduce this issue on the latest version please reopen the bug and attach the reproduction.