https://forums.autodesk.com/t5/net-forum/propertydescriptorcollection-find-causing-fatal-crash/m-p/10937219#M13708 <P>We have a long-running process in 2019 that we need AutoCAD to report messages to the console window.&nbsp; We are doing this by executing a Windows Forms DoEvents() to get AutoCAD to refresh the message in the console.&nbsp; However, this will occasionally cause a fatal crash with an exception "object reference not set to the instance of an object" with this stack trace:</P><P>&nbsp;</P><P><FONT size="2">System.NullReferenceException: Object reference not set to an instance of an object.</FONT><BR /><FONT size="2">at Autodesk.AutoCAD.Windows.Data.DynamicObjectBase.PropertyDescriptorCollection.Find(String name, Boolean ignoreCase)</FONT><BR /><FONT size="2">at Autodesk.AutoCAD.Ribbon.LayerComboText.LayerComboText_Loaded(Object sender, RoutedEventArgs e)</FONT></P><P><FONT size="2">Windows .NET messages ...</FONT></P><P>&nbsp;</P><P><FONT size="4">Is there a better way to get output messages while a process is running?&nbsp; Any ideas why this wouldn't work?</FONT></P> Tue, 08 Feb 2022 19:29:55 GMT mdaycock 2022-02-08T19:29:55Z https://forums.autodesk.com/t5/net-forum/propertydescriptorcollection-find-causing-fatal-crash/m-p/10937219#M13708 <P>We have a long-running process in 2019 that we need AutoCAD to report messages to the console window.&nbsp; We are doing this by executing a Windows Forms DoEvents() to get AutoCAD to refresh the message in the console.&nbsp; However, this will occasionally cause a fatal crash with an exception "object reference not set to the instance of an object" with this stack trace:</P><P>&nbsp;</P><P><FONT size="2">System.NullReferenceException: Object reference not set to an instance of an object.</FONT><BR /><FONT size="2">at Autodesk.AutoCAD.Windows.Data.DynamicObjectBase.PropertyDescriptorCollection.Find(String name, Boolean ignoreCase)</FONT><BR /><FONT size="2">at Autodesk.AutoCAD.Ribbon.LayerComboText.LayerComboText_Loaded(Object sender, RoutedEventArgs e)</FONT></P><P><FONT size="2">Windows .NET messages ...</FONT></P><P>&nbsp;</P><P><FONT size="4">Is there a better way to get output messages while a process is running?&nbsp; Any ideas why this wouldn't work?</FONT></P> Tue, 08 Feb 2022 19:29:55 GMT https://forums.autodesk.com/t5/net-forum/propertydescriptorcollection-find-causing-fatal-crash/m-p/10937219#M13708 mdaycock 2022-02-08T19:29:55Z