Retrieve text of a dynamically created text box

I am making an ASP.net web application where I dynamically create a textbox.

 

tdNilai = new TableCell();
txtNilaiRusak = new TextBox();
txtNilaiRusak.Attributes["id"] = arIdChild[b].ToString();
txtNilaiRusak.CssClass = "form-control create-number";

tdNilai.Controls.add(txtNilai);

tr.Controls.Add(tdNilai);
tblData.Controls.Add(tr);

 

 

Now I also have a save button and I need to find the text of the dynamically created text box so I can save it in a database.
Please help me.