Get data from ascx file

I create an ascx file. In ascx file I create a textBox with id "MyTXT".
I have ASPX file. on page load I write:

        Control MyASCX = LoadControl("my.ascx");
        Place_HOLDER.Controls.Add(MyASCX );
 I also have a botton in aspx page.
How can I By pressing this botton I want to get ASCX textbox value ( textbox.Text)?
(Sorry for my bad English) 

 

 
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