String.Format

string.Format("{0:##0.0}", (dblVal / ((dblTot == 0.0) ? 1 : dblTot)) * 100) + "%
" +String.Format("{0:0,0}", dblVal);
Composite formatting: http://msdn2.microsoft.com/en-us/library/txafckwd.aspx
Numbers, standard: http://msdn2.microsoft.com/en-us/library/dwhawy9k.aspx
Numbers, custom: http://msdn2.microsoft.com/en-us/library/0c899ak8.aspx
Datetime, standard: http://msdn2.microsoft.com/en-us/library/az4se3k1.aspx
Datetime, custom: http://msdn2.microsoft.com/en-us/library/8kb3ddd4.aspx http://msdn.microsoft.com/msdnmag/issues/06/01/ExtremeASPNET/def