Question : Print PowerPoint document from a C# application

I want to print PowerPoint documents from my C# .NET application.

First, I tried to simply reference the Automation interop libraries like this:

public void PrintFile(string myFilePath)
{
      Application oPowerPoint = new Application();
      Presentation oPresentation = null;

      oPowerPoint.Activate();
      oPresentation = oPowerPoint.Presentations.Open(myFilePath, MsoTriState.msoTrue, MsoTriState.msoFalse, MsoTriState.msoTrue);

      oPresentation.PrintOut(-1, -1, "", 1, MsoTriState.msoCTrue);

      oPresentation.Close();
      oPresentation = null;
      oPowerPoint.Quit();
      oPowerPoint = null;
}

But that leaves an instance of PowerPoint open on the desktop  which I dont want. I added ReleaseComObject calls before nulling out my references to the Presentation and PowerPoint objects, but that didnt have any affect.

      while (Marshal.ReleaseComObject(oPresentation) > 0) ;
      oPresentation = null;
      

      while (Marshal.ReleaseComObject(oPowerPoint) > 0) ;
      oPowerPoint = null;

Next, I added explicit garbage collection at the end:

      GC.Collect();
      GC.WaitForPendingFinalizers();

This closes the PowerPoint application, but it does it too soon! The application is closed before the print job is sent to the printer, so the print job is not completed.

How can I use PowerPoint to print presentations from my C# .Net code without leaving PowerPoint visible on the desktop?

Answer : Print PowerPoint document from a C# application

Check that Check the oPowerPoint.Options.PrintBackground is set to false. This will cause your code to wait until printout sucessufully finish to print your document.
The default is true which is causing you this issue.