Formating Excell Cells When Exporting Gridview To Excel

Add the style sheet with the below styles to the stream writer as below

Dim tw As New System.IO.StringWriter
Dim hw As New System.Web.UI.HtmlTextWriter(tw)
Dim styleInfo As String = ""
Dim styleInfo1 As String = ""


There are many other style you can apply to get correct date and number decimal points amount.

mso-number-format:"0" No Decimals
mso-number-format:"0\.00" 2 Decimals
mso-number-format:"mm\/dd\/yy" Date format
mso-number-format:"m\/d\/yy\ h\:mm\ AM\/PM" D -T AMPM
mso-number-format:"Short Date" 03/07/2009
mso-number-format:"Medium Date" 05-jan-2008
mso-number-format:"Short Time" 8:67
mso-number-format:"Medium Time" 8:67 am
mso-number-format:"Long Time" 8:67:25:00
mso-number-format:"Percent" Percent - two decimals
mso-number-format:"0\.E+00" Scientific Notation
mso-number-format:"\@" Text
mso-number-format:"\#\ ???\/???" Fractions - up to 3 digits (312/943)
mso-number-format:"\0022£\0022\#\,\#\#0\.00" £12.76
mso-number-format:"\#\,\#\#0\.00_ \;\[Red\]\-\#\,\#\#0\.00\ " 2 decimals, negative numbers in red and signed
(1.86 -1.66)
mso-number-format:"\\#\\,\\#\\#0\\.00_\\)\\;\\[Black\\]\\\\(\\#\\,\\#\\#0\\.00\\\\)" Accounting Format –5,(5)