The beauty of working with a framework like .NET is that when you have a problem, chances are, someone else did before you, and might have even resolved it for you. In our last post, I explained how to find text in a PowerPoint slide using C#. My goal was to translate it using the Google Translate service, and I intended to write my own code to call the web service and retrieve the translation. Turns out, there is a .NET API for Google Translate, ready to use, which does it for you already (of course, I found that out already after rolling out my own code, which wasn’t nearly as good).
Building up where we left off, I quickly wrote this class, which will translate the slide currently in view; I think the code is self-explanatory: get the slide, create a Google translator, pass it the language of origin and of destination, and translate every chunk of text you find! The only thing I needed to do was to download GoogleTranslateAPI_0.3.1, add the dll to the project as a reference.
using PowerPoint = Microsoft.Office.Interop.PowerPoint;
public class SlideTranslator
public static void TranslateSlide(Language from, Language to)
var googleTranslator = new TranslateClient("http://www.clear-lines.com");
var powerpoint = Globals.ThisAddIn.Application;
var slide = (PowerPoint.Slide)powerpoint.ActiveWindow.View.Slide;
foreach (PowerPoint.Shape shape in slide.Shapes)
if (shape.HasTextFrame == Microsoft.Office.Core.MsoTriState.msoTrue)
var textFrame = shape.TextFrame;
var textRange = textFrame.TextRange;
TranslateTextRange(textRange, googleTranslator, from, to);
public static void TranslateTextRange(
var paragraphs = textRange.Paragraphs(-1, -1);
foreach (PowerPoint.TextRange paragraph in paragraphs)
var text = paragraph.Text;
text = text.Replace("\r", "");
paragraph.Text = translator.Translate(text, from, to);
Later this week, after I do some code scrubbing, I’ll post the entire VSTO solution. Until then, have fun – it’s almost the week-end!