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PDF Viewer Unload document

I have loaded a PDF successfully in the control. But when I close the application or try to unload the PDF document using "Unload" function, I get this error:

An unhandled exception of type 'System.ArgumentNullException' occurred in Syncfusion.Pdf.Base.dll
Additional information: Der Wert darf nicht NULL sein.

Any idea how to solve that?

Version: 15.1451.0.37


3 Replies

BS Balasubramanian Sundararajan Syncfusion Team July 12, 2017 09:57 AM UTC

Hi Christoph, 

Thank you for using Syncfusion product. 

We are afraid that we are unable to reproduce “System.ArgumentNullException” thrown while unloading the PDF document from the PDF viewer control in Windows forms platform. We have created a simple sample to reproduce the reported exception and the sample can be downloaded from the following link, 

Can you please modify the above sample or provide us the sample with which the issue could be reproduced. Also provide the following details which will help us to analyze more and assist you better on the issue. 

PDF document: 
Syncfusion Essential Studio: 
Visual Studio: 
System Culture information:  
Operating System: 

Please let me know if you have any queries. 

Balasubramanian S 

GR Giancarlo Rantes February 12, 2021 10:00 PM UTC


I have the same problem.

I attach the example with the file that presents this problem

Attachment: Getting_Started_9bfb2e0b.rar

DD Divya Dhayalan Syncfusion Team February 15, 2021 08:28 PM UTC

Hi Giancarlo, 
Thanks for contacting Syncfusion support. 
We were tried to reproduce the issue based on the previous update in the forum and sample code, but we are unable to reproduce the reported “PdfViewer throws when on Unload” in our side. Based on the Forum details we suspect that you are using the Syncfusion product version 15.1 or 16.4. On analyzed further, we have found that we have resolved some issues in our recent days related to the same and the reported issue might be resolved in our latest version of PDF Viewer.  
Our latest version of NuGet package has been published in the nuget.org and please find the link below: https://www.nuget.org/packages/Syncfusion.PdfViewer.Windows  
So, we request you to try our latest version of PDF Viewer and let us know whether the issue is resolved. If you still face the issue, please provide us the following details that will be helpful for us to analyze more and provide you a better solution. 
1. Replication steps to reproduce the issue 
2. Syncfusion Product version.   
3. .Net Framework / .Net Core version. 
4. Operating System. 

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