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Created attachment 10682 [details]
Screen capture of the problem
[XVS.iOS 3.9 SR4] Attempting to set constraint priority causes crash due to NRE in "ConstraintPriorityPropertyEntry.spinButton_OnValueChanged()"
## Regressions status: REGRESSION somewhere between XamarinVS 3.9.483 and XamarinVS 3.9.533
BAD: Xamarin 3.11.271 (e36ba35) + Xamarin.iOS 184.108.40.206 (4dac6bf)
BAD: Xamarin 3.9.533 (66489f0) + Xamarin.iOS 220.127.116.11 (981acb3)
GOOD: Xamarin 3.9.483.0 (978be3d) + Xamarin.iOS 18.104.22.168 (ccfcd59)
## Steps to reproduce
1. Create a new Unified, iPhone, Single View application in Visual Studio.
2. Open "MainStoryboard.storyboard" in the designer.
3. Drag a UIButton from "Views -> Toolbox" into the View Controller.
4. With the UIButton in the view controller selected, click the green "plus" button in the iOS designer toolbar to add the recommended constraints.
5. Single-click the UIButton twice to enter constraints editing mode (do not double-click).
6. Drag a new constraint from the top of the button to the top of the view controller.
7. Select either of the duplicate constraints from the top of the button to the top of the view controller.
8. Change the length of the constraint to a different value using the "Properties -> Widget" window.
9. Lower the priority of the constraint to "900".
10. Click back in the iOS designer canvas (or anywhere else outside the priority text entry field).
Note: steps 6-10 are also demonstrated in the attached screen capture.
Visual Studio crashes.
### Excerpt from the top of the stack trace (collected by attaching a second instance Visual Studio to the original instance for debugging)
> System.NullReferenceException was unhandled
> Message: An unhandled exception of type 'System.NullReferenceException' occurred in WindowsBase.dll
> Additional information: Object reference not set to an instance of an object.
> at MonoTouch.Design.Client.Windows.ConstraintPriorityPropertyEntry.spinButton_OnValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
> at MonoTouch.Design.Client.Windows.SpinButton.SetStringValue()
> at MonoTouch.Design.Client.Windows.SpinButton.textBox_TextCommitted(Object sender, EventArgs e)
## Version information
### Windows 8.1 64-bit, in VMWare Fusion 6.0.5 (2209127)
Microsoft Visual Studio Professional 2013
Version 12.0.30723.00 Update 3
Microsoft .NET Framework
Xamarin 3.11.271.0 (e36ba35)
Xamarin.Android 22.214.171.124 (e81edcfee3152b5892337b8741d8da28f9ee74b1)
Xamarin.iOS 126.96.36.199 (3abf86b113ef9dd7c6aaf53c4c47bdb39ae526b9)
### OS X 10.9.5, MacBook Air
Xamarin.iOS 188.8.131.52 (Business Edition)
Build date: 2015-04-01 21:55:11-0400
Mono 4.0.0 ((detached/21d849b)
Xcode 6.1.1 (6611), Build 6A2008a
Created attachment 10683 [details]
Note: Xamarin Studio 5.9 on Mac does _not_ hit this bug.
I suspect bug 28782 might have the same underlying cause.
Thanks Jose! I think the commit in comment 3 still needs to be bumped to in XamarinVS.
Also merged to xvs-cycle5.
This is verified to be fixed in XVS 5.0.571
I have checked this issue with master and C5 branch and observed that this issue is fixed in master branch(XVS 5.0.572) but still exist in C5 branch(XVS 3.11.426). Detailed Observation is given below :
Master Branch : VS is not getting crashed after following steps given in Comment(0).
Screencast regarding same : http://www.screencast.com/t/E0prDHjdTfaF
Environment Info : https://gist.github.com/Shruti360/af6e682c86bc2c7c231b
C5 Release Branch : VS is still getting crashed after following steps given in Comment(0).
Screencast regarding same : http://www.screencast.com/t/mGe9LM52Pb
Environment Info : https://gist.github.com/Shruti360/8af0a426ae29567b9b8b
The fix was just merged to the release branch. We just need VS to trigger a build with the fixes included :)
I have checked this issue with C5 XVS 3.11.428 and observed that VS is not getting crash after following steps given in Comment(0).
Screencast regarding same : http://www.screencast.com/t/SswHuIoyM
Environment Info : https://gist.github.com/Shruti360/636773fdb8ed8cad361f
Hence, Closing this issue.