C# and MS Word , range.font.bold doesn't work

I wand to bold a range on MS Word do开发者_JAVA百科cument using C#. The code is :

Range.Font.Bold=1;

When I look at the documnet I see that the bold button is on but the text is not bold.

The same probalem appear when I use Selection method .

Any idea?

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I believe it's -1 and not 1

http://social.msdn.microsoft.com/Forums/en-ZA/vsto/thread/ec35e23b-22a5-4ffa-95cc-2d5b90d86dd2

Range.Font.Bold = -1;