How to pass datatable value one form to other form using asp.net

Through viewstate you cannot carry data from one page to another page. ViewState data will be avaialable for pariculat page.

For your case use session it will carry data from one page to another page.
Note : Don't forgot to clear session variables.

Examples :
C# :

Page 1 
DataTable dtTest =new DataTable();
Session["data"]=dtTest;

Page 2
DataTable dt=new DataTable();
dt=(DataTable)Session["data"];

VB :
Page 1

Dim dtTest as DataTable=new DataTable()
Session("data")=dtTest

Page 2
Dim dt as DataTable=new DataTable()
dt=CType(Session("data"), DataTable)