How to get property of a dynamically loaded user control

I have a user control (uc1.ascx) with a property (p), and its user interface includes a textbox. The value of "p" depends on what user types in the textbox.

I dynamically load uc1 in my page_load event (2 copies):
1 for (int i = 0; i <= 1; i++)
2 {
3 Control uc1 = LoadControl("uc1.ascx");
4 Table1.Rows[i].Cells[0].Controls.Add(uc1);
5 }
 
After the page_load event, I can see 2 copies of my user control on web form.
User now types in the textbox some text, and the property (p) is set.

Question is: how can I get the values of the properties for the 2 user controls respectively?

 
...