It is possible to cross page postback.you can try this code.
**************Default.aspx******************
| Enter Class Name |
|
| Enter Techers Name |
|
|
|
***************Default2.aspx********************
******************Default2.aspx.cs***********************
protected void Page_Load(object sender, EventArgs e)
{
if (PreviousPage != null && PreviousPage.IsCrossPagePostBack)
{
TextBox txtcname = (TextBox)PreviousPage.FindControl("txtclassname");
TextBox txttname = (TextBox)PreviousPage.FindControl("txttechername");
lblcname.Text = "
Your Class is:-    " + txtcname.Text;
lbltname.Text = "
Your Teacher Name is:-   " + txttname.Text;
}
else
{
Response.Redirect("Default.aspx");
}
}