LINQPad script to migrate PowerPoint files from .ppt to .pptx using Microsoft.Office.Interop.Powerpoint

PowerPointConversionAutomation.cs

//using office 14.0.0.0
//using Microsoft.Office.Interop.Powerpoint

//http://msdn.microsoft.com/en-us/library/microsoft.office.interop.powerpoint._application(v=office.14).aspx
public static Microsoft.Office.Interop.PowerPoint.Application ppt { get; set; }

void Main()
{
    ppt = new Microsoft.Office.Interop.PowerPoint.Application();
    MigratePPT(@"C:\Users\MyFiles");
}

private static void MigratePPT(string path)
{
    //Find all .ppt files recursively for given path
    System.IO.DirectoryInfo di = new System.IO.DirectoryInfo(path);
    FileInfo[] files = di.GetFiles("*.ppt", SearchOption.AllDirectories);
    
    //NOTE: will overwrite files with same name if they have .pptx extension
    foreach(FileInfo file in files)
    {
        if(file.Extension != ".pptx")
        {
            Console.WriteLine(string.Format("Converting {0}",file.FullName));
            //open presentation
            Presentation presentation = ppt.Presentations.Open(file.FullName, MsoTriState.msoFalse, MsoTriState.msoFalse, MsoTriState.msoFalse);
            //add 'x' to end of filename
            presentation.SaveAs(string.Format("{0}x",file.FullName), PpSaveAsFileType.ppSaveAsOpenXMLPresentation); 
            //close presentation
            presentation.Close(); 
        }
    }
    
    ppt.Quit();
    Cleanup();
}

private static void Cleanup()
{
    GC.Collect(); 
    GC.WaitForPendingFinalizers(); 
    // GC needs to be called twice in order to get the Finalizers called 
    // - the first time in, it simply makes a list of what is to be  
    // finalized, the second time in, it actually is finalizing. Only  
    // then will the object do its automatic ReleaseComObject. 
    GC.Collect(); 
    GC.WaitForPendingFinalizers(); 
}