opening new window on clicking botton using c#

Question

i am adding data in one page of aspx & i want to display
that stored data in new window how to do that in asp.net using c# And opening
the data of particular person or id how to do plz help.
i am also trying that on botton click geturl
protected void geturl(object sender, EventArgs e)
{ 
 string strTxt= Admissiontxt.Text; 
Response.Redirect("showregistration.aspx?pk=" + strTxt);
}