PPT to PDF Conversion in C#: NullReferenceException: Object Reference Not Set

Aspose.Slides Product Family
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1

Hi

I am trying to convert a few ppts to pdf and I am getting the following null reference exception.

System.NullReferenceException: Object reference not set to an instance of an object.
at .(Graphics ,  ,  )
at .(IList1 ,  ,  ) at .( ) at .( ) at .( ) at .( , & , MathJustification ,  , Single ) at .( , MathJustification ,  , Single ) at e.ee( , Boolean , Single ) at ee.(e ) at ee.() at .( ,  ) at ..ctor( , Int32 , Int32 ) at .() at ..ctor(TextFrame ,  , IBaseSlide ,  , [] ) at e.e( ,  ) at e.e( ) at e.(Boolean ) at e.ee(Boolean ) at e.( ,  , InterruptionToken ) at .( ,  , InterruptionToken ) at .( , IShapeFrame ,  , Boolean , Boolean , InterruptionToken ) at Aspose.Slides.Slide.(Boolean ,  , e , List1 , InterruptionToken )
at .(Presentation , Stream , Int32[] , PdfOptions , InterruptionToken )
at Aspose.Slides.Presentation.Save(Stream stream, SaveFormat format, ISaveOptions options)

what is the root cause and fix for this?

Thank you

2

@himanshu_surana

Cause

The NullReferenceException you’re encountering during the conversion of PowerPoint presentations to PDF typically indicates that the code is trying to access an object that hasn’t been instantiated. This can occur due to various reasons, such as missing elements in the presentation, unsupported features, or issues with the specific PowerPoint file being processed.

Solution

To troubleshoot and resolve this issue, consider the following steps:

  1. Check the Presentation File: Ensure that the PowerPoint files you are trying to convert are not corrupted and are compatible with Aspose.Slides. Try opening them in PowerPoint to verify their integrity.

  2. Update Aspose.Slides: Make sure you are using the latest version of Aspose.Slides for .NET. Updates often include bug fixes and improvements that could resolve your issue.

  3. Use Try-Catch: Implement error handling in your code to catch exceptions and log more details about the state of your application when the error occurs. This can help you identify which part of the presentation is causing the issue.

  4. Simplify the Presentation: If possible, try converting a simpler presentation first. If that works, gradually add elements from the original presentation to identify what might be causing the problem.

  5. Check for Unsupported Features: Review the documentation for any features in your PowerPoint presentations that may not be supported by Aspose.Slides. Remove or modify these features if necessary.

Code

Here’s a basic example of how to convert a PowerPoint presentation to PDF using Aspose.Slides:

using Aspose.Slides;
using Aspose.Slides.Export;

string srcFileName = "path_to_your_presentation.pptx";
string destFileName = "path_to_output.pdf";

try
{
    // Instantiate a Presentation object that represents a presentation file
    using (Presentation pres = new Presentation(srcFileName))
    {
        // Save the presentation to PDF
        pres.Save(destFileName, SaveFormat.Pdf);
    }
}
catch (NullReferenceException ex)
{
    Console.WriteLine("A null reference exception occurred: " + ex.Message);
    // Additional logging or handling can be done here
}
catch (Exception ex)
{
    Console.WriteLine("An unexpected error occurred: " + ex.Message);
    // Additional logging or handling can be done here
}

**Next Steps**

If the issue persists after trying the above steps, please reach out to Aspose support with the specific PowerPoint file that is causing the issue, along with the code you are using. This will help us provide more targeted assistance.

I hope this helps you resolve the issue! If you have any further questions, feel free to ask.
3

@himanshu_surana,
Thank you for reporting on the issue. We are sorry that you encountered this problem. We need more details to investigate the case. Please share the following additional files and information:

  • The sample presentation file
  • The code example to reproduce the exception
  • The OS version on which the error occurs
  • The .NET target platform in your application project
  • The Aspose.Slides version you are using