在打印时如何度量字符串？

     <Question>
  When programming printing code, how to measure string?
  <Answers>
  Yang Ning:
  You can't use Graphics.MeasureString Function, and must use typographic StringFormat object.
  Reason is: when printing string size is resolution-dependent.
  And if you using MeasureString function or use defaultgraphic StringFormat object, it is resolution-independent,
  the result will be smaller than the true one.
  Below is sample code:
  
   Public Shared Function GetTextSize(ByVal g As Graphics, _
   ByVal text As String, _
   ByVal textFont As Font) As SizeF
  
   If text.Length = 0 Then Return New SizeF(0, 0)
  
   Dim s As StringFormat = StringFormat.GenericTypographic
   s.FormatFlags = StringFormatFlags.MeasureTrailingSpaces
  
   Dim textRect As RectangleF
   Dim characterRanges As CharacterRange() = {New CharacterRange(0, text.Length)}
   s.SetMeasurableCharacterRanges(characterRanges)
   textRect = g.MeasureCharacterRanges(text, textFont, New RectangleF(0, 0, 4000, 4000), s)(0).GetBounds(g)
   Return New SizeF(textRect.Right, textRect.Bottom)
   End Function
  
  BTW:
  We found a bug when we use code like above. The bug is FlexGrid's column caption will display disorder. So We use following code instead
  
   Public Shared Function GetTextSize(ByVal g As Graphics, _
   ByVal text As String, _
   ByVal textFont As Font) As SizeF
  
   If text.Length = 0 Then Return New SizeF(0, 0)
  
   Dim s As StringFormat = StringFormat.GenericTypographic
   Dim oldFlags As StringFormatFlags
  
   oldFlags = s.FormatFlags
   s.FormatFlags = StringFormatFlags.MeasureTrailingSpaces
   Try
   Dim textRect As RectangleF
  Dim characterRanges As CharacterRange() = {New CharacterRange(0, text.Length)}
   s.SetMeasurableCharacterRanges(characterRanges)
   textRect = g.MeasureCharacterRanges(text, textFont, New RectangleF(0, 0, 4000, 4000), s)(0).GetBounds(g)
   Return New SizeF(textRect.Right, textRect.Bottom)
  Finally
  StringFormat.GenericTypographic.FormatFlags = oldFlags
  End Try
   End Function