🤔 I thought maybe this would be easy, but apparently it isn't...

https://github.com/PowerShell/GraphicalTools/blob/master/src/OutGridView.Gui/Views/DataGridView.xaml#L23 would seem to indicate there's a copy mode. Setting it to ExcludeHeader as per the docs results in an exception when you try to copy:

Unhandled exception. System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
 ---> System.ArgumentException: The value "15" is not of type "OutGridView.Models.IValue" and cannot be used in this generic collection. (Parameter 'value')
   at System.Collections.Generic.Dictionary`2.System.Collections.IDictionary.set_Item(Object key, Object value)
   at Avalonia.Markup.Parsers.Nodes.StringIndexerNode.SetTargetValueCore(Object value, BindingPriority priority)           at Avalonia.Data.Core.BindingExpression.OnNext(Object value)
   at Avalonia.Reactive.AvaloniaPropertyObservable`1.Subscribed(IObserver`1 observer, Boolean first)
   at Avalonia.Reactive.LightweightObservableBase`1.Subscribe(IObserver`1 observer)
   at Avalonia.Data.BindingOperations.Apply(IAvaloniaObject target, AvaloniaProperty property, InstancedBinding binding, Object anchor)
   at Avalonia.AvaloniaObjectExtensions.Bind(IAvaloniaObject target, AvaloniaProperty property, IBinding binding, Object anchor)
   at Avalonia.Controls.DataGridColumn.GetCellValue(Object item, IBinding binding)
   at Avalonia.Controls.DataGrid.ProcessCopyKey(InputModifiers modifiers)
   at Avalonia.Controls.DataGrid.ProcessDataGridKey(KeyEventArgs e)
   at Avalonia.Controls.DataGrid.DataGrid_KeyDown(Object sender, KeyEventArgs e)
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Delegate.DynamicInvokeImpl(Object[] args)
   at Avalonia.Interactivity.Interactive.RaiseEventImpl(RoutedEventArgs e)
   at Avalonia.Interactivity.Interactive.BubbleEvent(RoutedEventArgs e)
   at Avalonia.Interactivity.Interactive.RaiseEvent(RoutedEventArgs e)
   at Avalonia.Input.KeyboardDevice.ProcessRawEvent(RawInputEventArgs e)
   at Avalonia.Input.InputManager.ProcessInput(RawInputEventArgs e)
   at Avalonia.Win32.WindowImpl.WndProc(IntPtr hWnd, UInt32 msg, IntPtr wParam, IntPtr lParam)
   at Avalonia.Win32.Interop.UnmanagedMethods.DispatchMessage(MSG& lpmsg)
   at Avalonia.Win32.Win32Platform.RunLoop(CancellationToken cancellationToken)
   at Avalonia.Threading.Dispatcher.MainLoop(CancellationToken cancellationToken)
   at Avalonia.Application.Run(CancellationToken token)
   at OutGridView.Application.AvaloniaAppRunner.AppMain(Application app) in C:\code\GraphicalTools\src\OutGridView.Gui\AvaloniaAppRunner.cs:line 62
   at OutGridView.Application.AvaloniaAppRunner.RunApp(ApplicationData applicationData) in C:\code\GraphicalTools\src\OutGridView.Gui\AvaloniaAppRunner.cs:line 44
   at OutGridView.Application.Program.Main(String[] args) in C:\code\GraphicalTools\src\OutGridView.Gui\Program.cs:line 32

Noting that the value changes based on which line you try to copy, we might need to add a handler or something for it.

@corbob do you think we could get an issue going on Avalonia for this?

@TylerLeonhardt I don't think an issue is happening with Avalonia, everything that I'm seeing indicates that even with WPF you need to create your own Copy handler, I just can't seem to get it to work (hence the question in discord about attaching a debugger). I'll spend some time on Monday trying to get a copy handler.