gtk Platform throw Exception: Object reference not set to an instance of an object.

[hxbb00]

Actual Behavior

Object reference not set to an instance of an object.

Code that Demonstrates the Problem

Exception in Gtk# callback delegate
  Note: Applications can use GLib.ExceptionManager.UnhandledException to handle the exception.
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
 ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at Eto.GtkSharp.Forms.GtkWindow`3.GtkWindowConnector.HandleWindowSizeAllocated(Object o, SizeAllocatedArgs args)
   --- 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 GLib.Signal.ClosureInvokedCB(Object o, ClosureInvokedArgs args)
   at GLib.SignalClosure.MarshalCallback(IntPtr raw_closure, IntPtr return_val, UInt32 n_param_vals, IntPtr param_values, IntPtr invocation_hint, IntPtr marshal_data)
   at GLib.ExceptionManager.RaiseUnhandledException(Exception e, Boolean is_terminal)
   at GLib.SignalClosure.MarshalCallback(IntPtr raw_closure, IntPtr return_val, UInt32 n_param_vals, IntPtr param_values, IntPtr invocation_hint, IntPtr marshal_data)
   at Gtk.Application.Run()
   at Eto.GtkSharp.Forms.ApplicationHandler.Run()
   at Eto.Forms.Application.Run(Form mainForm)

Specifications

• Version:2.5.3
• Platform(s): Gtk3
• Operating System(s): Windows 10

[cwensley]

Hey @hxbb00, thanks for reporting the issue! Do you have an example that causes the issue, or steps to reproduce?

[hxbb00]

sorry for late,debug with dnspy,crashed at Eto/src/Eto.Gtk/Forms/GtkWindow.cs

GtkWindow<TControl, TWidget, TCallback> handler = this.Handler;

Eto.Drawing.Size size = handler.Size;// System.NullReferenceException: Object reference not set to an instance of an object.

if (handler.Control.IsRealized)
{
	Eto.Drawing.Size? size2 = this.oldSize;
	Eto.Drawing.Size size3 = size;
	if (size2 == null || (size2 != null && size2.GetValueOrDefault() != size3))
	{
		TCallback callback = handler.Callback;
		callback.OnSizeChanged(this.Handler.Widget, EventArgs.Empty);
		if (handler.WindowState == Eto.Forms.WindowState.Normal)
		{
			handler.restoreBounds = new Eto.Drawing.Rectangle?(handler.Widget.Bounds);
		}
		this.oldSize = new Eto.Drawing.Size?(size);
	}
}

[hxbb00]

@cwensley

[hxbb00]

[hxbb00]

ButtonMenuItemConnector also null pointer

[cwensley]

Hey @hxbb00, thanks for referencing where the error is occurring, but do you have some of your code that demonstrates how to replicate this crash?

[hxbb00]

Hey @hxbb00, thanks for referencing where the error is occurring, but do you have some of your code that demonstrates how to replicate this crash?

my project environment is huge,the files is almost 2Gb,and i do not know how it happen,can not write a tiny demo,i will continue to find the reason,Thanks for your attention

[cwensley]

Ok no problem, please let me know if you do ever find out what is going on or if you can narrow it down with a demo app. I'm not sure what to do with this crash otherwise.

One thing I'd look for is perhaps you are calling/creating UI methods/classes in a non-UI thread. Hope this helps!