Bug 41079 - Can't deploy default Android application to Visual Studio Android Emulator: NullReferenceException is shown in the logs
Summary: Can't deploy default Android application to Visual Studio Android Emulator: N...
Status: RESOLVED NOT_REPRODUCIBLE
Alias: None
Product: Visual Studio Extensions
Classification: Xamarin
Component: Android ()
Version: unspecified
Hardware: PC Windows
: --- normal
Target Milestone: ---
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2016-05-13 16:11 UTC by Rostik
Modified: 2016-06-07 15:05 UTC (History)
3 users (show)

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

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Status:
RESOLVED NOT_REPRODUCIBLE

Description Rostik 2016-05-13 16:11:31 UTC
I created a blank Android application in Visual Studio 2015 and clicked on Debug button with selected emulator "Kitkat XXHDPI Phone (Android 4.4)". 

*Result*: Emulator is started, deployment of an app hangs. 

In the logs at %localappdata%\Xamarin\Logs\14.0\*.lde.log I see:

Xamarin.VisualStudio.UnhandledExceptionsManager Error: 0 : [2016-05-13 17:14:41.3935] Unhandled exception.
System.NullReferenceException: Object reference not set to an instance of an object.
   at System.Windows.Forms.ListBox.ItemArray.GetItem(Int32 virtualIndex, Int32 stateMask)
   at System.Windows.Forms.ListBox.ObjectCollection.get_Item(Int32 index)
   at Xamarin.VisualStudio.Android.DeviceChooser.UpdateList(IList`1 devices) in C:\Users\builder\data\lanes\3062\0dd817c0\source\XamarinVS\src\Core\VisualStudio.Android\UserControls\DeviceChooser.cs:line 157
   at Xamarin.VisualStudio.Android.DeviceChooser.<.ctor>b__7_1(Object sender, IEnumerable`1 args) in C:\Users\builder\data\lanes\3062\0dd817c0\source\XamarinVS\src\Core\VisualStudio.Android\UserControls\DeviceChooser.cs:line 29
   at System.EventHandler`1.Invoke(Object sender, TEventArgs e)
   at Xamarin.VisualStudio.Android.MonoAndroidDeviceProvider.<UpdateDevicesAsync>b__13_0() in C:\Users\builder\data\lanes\3062\0dd817c0\source\XamarinVS\src\Core\VisualStudio.Android\Devices\MonoAndroidDeviceProvider.cs:line 124
   at System.Threading.Tasks.Task.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()

*Workaround*:
- Cancel build
- Use Build -> Deploy
Comment 1 Juan Marcelo Tondato 2016-05-18 14:45:55 UTC
Could you attach the VSX logs (Help\Xamarin) and the result of the build in diagnostic mode >

To set build output in diagnostic mode plese go to "Tools\Options\Projects and Solutions\Build and Run" and set the property "MSBuild project build output verbosity" with "Diagnostic".
Comment 2 Rostik 2016-06-07 15:05:38 UTC
The problem went away after I upgraded to latest stable 4.0.4.4