How to add value into Textbox from Textboxlist

Question

I have below code to add int n into Textbox from Textboxlist, but when running this program, both textboxes dont have anything. Thanks in advance for any suggestion

private void btnLoad_Click(object sender, RoutedEventArgs e)
{
List<TextBox> IDtextBoxList = new List<TextBox>();
IDtextBoxList.Add(new TextBox { Text = txtboxpbM1.Text });
IDtextBoxList.Add(new TextBox { Text = txtboxpbM2.Text });
for (int n = 0; n < IDtextBoxList.Count; n++)
{
IDtextBoxList[n].Text = n.ToString();
}
}