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Michael Thrift
Posts: 41
Joined: 2015-06-09
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We recently upgraded our Excel Addin from using Addin Express 8.2.4371.2005 to 9.4.4644.0
We made this upgrade to keep up with the DPI Compatibility issues on Windows 10 and the Windows 10 upgrade that causes the keyboard hook issue.
Anyway, I am able to build and register the project without any errors. But when debugging I get:
An unhandled exception of type 'System.NullReferenceException' occurred in AddinExpress.XL.2005.dll
Additional information: Object reference not set to an instance of an object.
This occurs when I call a Show() or ShowDialog() on a custom form. Often times I'm marshalling this back on the main thread. The error occurs at:
AddinExpress.XL.2005.dll!AddinExpress.XL.ADXExcelTaskPanesManager.OnHookHostEraseBackground(System.IntPtr hwndHost, System.IntPtr hdc) Unknown
AddinExpress.XL.2005.dll!AddinExpress.Extensions.ADXCustomHostHook.DoHostEraseBackground(System.IntPtr hwndHost, System.IntPtr hdc) Unknown
AddinExpress.XL.2005.dll!AddinExpress.Extensions.ADXXLMessageHook.DefaultHandler(bool currentThread, ref AddinExpress.Extensions.WindowsAPI.CWPSTRUCT msg) Unknown
AddinExpress.XL.2005.dll!AddinExpress.Extensions.ADXMessageHook.CallbackFunction(int code, System.IntPtr wParam, System.IntPtr lParam) Unknown
[Native to Managed Transition]
[Managed to Native Transition]
AddinExpress.MSO.2005.dll!AddinExpress.MSO.ADXAddinModule.ThreadHookProc(int nCode, System.IntPtr wParam, System.IntPtr lParam) Unknown
[Native to Managed Transition]
[Managed to Native Transition]
PresentationFramework.dll!System.Windows.Window.ShowHelper(object booleanBox) Unknown
PresentationFramework.dll!System.Windows.Window.Show() Unknown
PresentationFramework.dll!System.Windows.Window.ShowDialog() Unknown
I am using the Dispatcher.Invoke method to display the form. |
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Posted 12 Sep, 2019 11:10:18
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Michael Thrift
Posts: 41
Joined: 2015-06-09
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To help, I also was able to get the same exception simply by closing the Document Recovery panel in Excel. As soon as I closed it, the same NullReference Exception was thrown in AddinExpress.XL.2005.dll.
The Addin loaded without error, but when closing the Document Recover panel, the below code was executed and errored. None of my own code ran.
> AddinExpress.XL.2005.dll!AddinExpress.XL.ADXExcelTaskPanesManager.OnHookHostEraseBackground(System.IntPtr hwndHost, System.IntPtr hdc) Unknown
AddinExpress.XL.2005.dll!AddinExpress.Extensions.ADXCustomHostHook.DoHostEraseBackground(System.IntPtr hwndHost, System.IntPtr hdc) Unknown
AddinExpress.XL.2005.dll!AddinExpress.Extensions.ADXXLMessageHook.DefaultHandler(bool currentThread, ref AddinExpress.Extensions.WindowsAPI.CWPSTRUCT msg) Unknown
AddinExpress.XL.2005.dll!AddinExpress.Extensions.ADXMessageHook.CallbackFunction(int code, System.IntPtr wParam, System.IntPtr lParam) Unknown
[Native to Managed Transition]
[Managed to Native Transition]
AddinExpress.MSO.2005.dll!AddinExpress.MSO.ADXAddinModule.ThreadHookProc(int nCode, System.IntPtr wParam, System.IntPtr lParam) Unknown
[AppDomain Transition]
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Posted 12 Sep, 2019 11:19:29
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Michael Thrift
Posts: 41
Joined: 2015-06-09
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The newer version of Addin Express introduces a new Excel event hook:
_excelHook.HostEraseBackground += OnHookHostEraseBackground
When this event fires it loops through TaskPaneInstances in each of the ADXExcelTaskPanes in the Items collection. But i don't think it handles the possibility of the ADXExcelTaskPane object being null.
On the AddinStartUpComplete event we create a new ADXExcelTaskPanesCollectionItem as a placeholder. It is not visible initially, and is used to host different task panes based on users selecting different "Apps".
But because this is getting created at the onset, the OnHookHostEraseBackground method is finding this and the error is thrown when it doesn't find a TaskPane. |
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Posted 12 Sep, 2019 12:22:09
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Michael Thrift
Posts: 41
Joined: 2015-06-09
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I was able to debug the code. The original code that errors:
foreach (ADXExcelTaskPane pane in item.TaskPaneInstances)
{
if (pane.Injected && pane.HostHandle == hwndHost)
{
ADXContainerControl container = pane.ContainerControl;
if (container != null)
{
Graphics dc = Graphics.FromHdc(hdc);
SolidBrush br = new SolidBrush(container.BackColor);
WindowsAPI.WINDOWPOS wpos = container.ScreenPos;
dc.FillRectangle(br, wpos.x, wpos.y, wpos.cx, wpos.cy);
br.Dispose();
dc.Dispose();
}
}
}
I simply added a null check on TaskPaneInstances and my addin worked as expected. Can you verify this is a defect?
if (item.TaskPaneInstances !=null)
{
foreach (ADXExcelTaskPane pane in item.TaskPaneInstances)
{
if (pane.Injected && pane.HostHandle == hwndHost)
{
ADXContainerControl container = pane.ContainerControl;
if (container != null)
{
Graphics dc = Graphics.FromHdc(hdc);
SolidBrush br = new SolidBrush(container.BackColor);
WindowsAPI.WINDOWPOS wpos = container.ScreenPos;
dc.FillRectangle(br, wpos.x, wpos.y, wpos.cx, wpos.cy);
br.Dispose();
dc.Dispose();
}
}
}
}
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Posted 12 Sep, 2019 13:16:36
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Alexander Solomenko
Posts: 140
Joined: 2009-02-27
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Hi Michael,
Thank you for your cooperation. This is our mistake indeed. We have already made corrections, and they will be included into the next release. If you need the updated assemblies, I can send them to you.Regards,
Aleksandr Solomenko |
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Posted 13 Sep, 2019 03:28:44
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Michael Thrift
Posts: 41
Joined: 2015-06-09
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Alexander - can you confirm that this issue would be on other events as well, such as OnHookDPIChanged? Does your fix include handling null reference on that event?
We are seeing a similar crash now when user's resize their window. We expect this is causing the DPI change event to fire.
If the updated assembly has this fix in place, I wouldn't mind having a copy of it. I may not be aware of all places you have made a correction. |
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Posted 16 Sep, 2019 13:09:03
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Andrei Smolin
Add-in Express team
Posts: 18817
Joined: 2006-05-11
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Hello Michael,
I've sent you an email containing a download link and instruction describing how to install the assembly(ies) providing the fix.
Andrei Smolin
Add-in Express Team Leader |
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Posted 17 Sep, 2019 10:19:41
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