Chris,

Sorry I should have explained a bit better. The code below is a test property I created that accesses a test field call _testSize inside the class.

private Size _testSize;

[DefaultValue(typeof(System.Drawing.Size), "100, 45")]
public Size TestSize
{
   get { return _testSize; }
   set
   {
      _testSize = value;
   }
}

If you look at the help for the DefaultValueAttribute class (attribute) and look at the available constructors you can see the following constructor signature.

public DefaultValueAttribute(
   Type type,
   string value
);

The string value must be compatible with your types TypeConverter, in this case:-

System.Drawing.SizeConverter

This allows you to reset complex types that the DefaultValueAttribute has no specific knowledge of.

Regards
Neil