NullReference Exception when evaluating variables

AlterNET Studio Support
,
1
Hello,
when debugging script code we get the following error message. The error can be reproduced by stepping through the code in quick succession (Step into F11) while evaluating the local variables.
ucLocals.EvaluateVariables((await Debugger.GetVariablesInScopeAsync()).VariableNames);
Is this a known problem and is there already a solution?
Regards
Thorsten
The exception message is:
Beschreibung: Der Prozess wurde aufgrund einer unbehandelten Ausnahme beendet.
Ausnahmeinformationen: System.NullReferenceException
bei Alternet.Scripter.Debugger.UI.Wpf.EvaluationResultsTreeController+<>c__DisplayClass13_0+<b__1>d.MoveNext()
bei System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
bei System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(System.Threading.Tasks.Task)
bei Alternet.Scripter.Debugger.UI.Wpf.EvaluationResultsTreeController+d__18.MoveNext()
bei System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
bei System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(System.Threading.Tasks.Task)
bei Alternet.Scripter.Debugger.UI.Wpf.EvaluationResultsTreeController+d__19.MoveNext()
bei System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
bei System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(System.Threading.Tasks.Task)
bei Alternet.Scripter.Debugger.UI.Wpf.EvaluationResultsTreeController+d__13.MoveNext()
bei System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
bei System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(System.Threading.Tasks.Task)
bei Alternet.Scripter.Debugger.UI.Wpf.Locals+<>c__DisplayClass12_0+<b__0>d.MoveNext()
bei System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
bei System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(System.Threading.Tasks.Task)
bei Alternet.Scripter.Debugger.UI.Wpf.VariablesEvaluationControlBase+d__14.MoveNext()
bei System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
bei System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(System.Threading.Tasks.Task)
bei Alternet.Scripter.Debugger.UI.Wpf.Locals+d__12.MoveNext()
bei System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
bei System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate, System.Object, Int32)
bei System.Windows.Threading.ExceptionWrapper.TryCatchWhen(System.Object, System.Delegate, System.Object, Int32, System.Delegate)
bei System.Windows.Threading.DispatcherOperation.InvokeImpl()
bei MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(System.Object)
bei System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
2
Hello,
We tried to reproduce this issue, but with no success so far.
regards,
Andrew
3
Hello,
the issue can be reproduced with below code (from the hello world sample) and your Extensibility Studio Demo.
Just set a breakpoint at line 32: doc.Childrens.Add(new Document(doc));
and press F10 key very often and quickly.
Here the sample code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.IO;

namespace HelloWorld.Wpf
{
///
/// Interaction logic for MainWindow.xaml
///
public partial class MainWindow : Window
{
public MainWindow()
{
var x = this;

var doc = new Document(null);
for (int i = 0; i < 10; i++)
{
doc.Childrens.Add(new Document(doc));
}
InitializeComponent();
}

private void button1_Click(object sender, System.Windows.RoutedEventArgs e)
{
Close();
}
}
public class Document
{
public Document(Document parent)
{
Parent =parent;
Childrens = new List();

_media =new List();
for (int i = 0; i < 10; i++)
{
_media.Add(new Medium());
}
_pages =new List();
for (int i = 0; i < 10; i++)
{
_pages.Add(new Page(this));
}
}
public Document Parent{ get;}
public List Childrens { get; set; }

private List _pages;

public List Pages
{
get { return _pages; }
set { _pages = value; }
}

private List _media;

public List Media
{
get { return _media; }
set { _media = value; }
}
}
public class Page
{
public Page(Document document)
{
Document = document;
_media = new List();
}


public Document Document { get; }


public Medium DefaultMedium { get; set; }


private List _media;

public List Media
{
get { return _media; }
set { _media = value; }
}
private bool _rear;

public bool Rear
{
get { return _rear; }
set { _rear = value; }
}
}
public class Fields
{
private string _name;

public string Name
{
get { return _name; }
set { _name = value; }
}

private string _value;

public string Value
{
get { return _value; }
set { _value = value; }
}
}
public class Medium
{
public Medium()
{
Id = Guid.NewGuid().ToString();
}
public string Id { get; set; }

private string _name;

public string Name
{
get { return _name; }
set { _name = value; }
}

private Stream _stream;

public Stream Stream
{
get { return _stream; }
set { _stream = value; }
}
}
}
4
Hello,
I've sent you fix via e-mail.
Could you please try it and let me know whether this problem was fixed?
regards,
Andrew