how to retrieve contents from dynamically created textboxes

[lamiajoyee]

hello im creating textboxes and their number depends on the contents of a dropdownlist.

protected void dropDownList_SelectedIndexChanged(object sender,EventArgs e)
{
int number=int.parse(dropdownitem.Text);
for(int i=0;i<number;i++)
{
TextBox tb=new TextBox();
tb.ID="tb"+i.ToString();
Panel1.Controls.Add(tb);   //placing the textboxes on a panel
}
}

now i want to retrieve the data from these textboxes. but my approach is not clear

protected void button1_Click(object sender,Eventargs e)
{
for(int i=0;i<Request.Form.Count;i++)
{
string strid="tb"+i.ToString();
string value=Request.Form[strid].ToString();
}
}

this is definitely not working.can you suggest something that serves my purpose? thanks in advance