David M. Kean - MSFT MSFT, Moderator
Basically the Convert class makes it easier to convert between all the base types.
The Convert.ToInt32(String, IFormatProvider) underneath calls the Int32.Parse. So the only difference is that if a null string is passed to Convert it returns 0, whereas Int32.Parse throws an ArgumentNullException.
It is really a matter of choice whichever you use.
Also have a look at the new .NET 2.0 method Int32.TryParse, which attempts to convert a string to an int without throwing an exception.