gvDetails.EditIndex = e.NewEditIndex;

USE EDIT FUNCTION AND GET THE VALUE IN TO ANY LABEL OR TEXT BOX OF THE SAME PAGE AND SET VISIBLE FALSE FOR THAT .....

AND THEN IN THE NEXT PAGE USE CROSS PAGE POSTING

TextBox pp_Textbox1;
       
        pp_Textbox1 = (TextBox)PreviousPage.FindControl("Textbox1");

        Label1.Text = "Hello " + pp_Textbox1.Text +";

IT MAY HEL-P U