On page _load find control recursive function return null

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C#

ASP.NET

C#4.0

ASP.NET4

i use this function for find control on page its working fine on button click but not working on page load its return null.

public  Control FindControlRecursive(Control container, string name)
   {
       if (container.ID == name)
           return container;

       foreach (Control ctrl in container.Controls)
       {
           Control foundCtrl = FindControlRecursive(ctrl, name);

           if (foundCtrl != null)
               return foundCtrl;
       }
       return null;
   }

foreach (var result in results)
            {
   TextBox tot = (TextBox)FindControlRecursive(Page, "Total" + i);
   TextBox obtd = (TextBox)FindControlRecursive(Page, "Obtd" + i);
   TextBox pre = (TextBox)FindControlRecursive(Page, "Pre" + i);
   extBox grade = (TextBox)FindControlRecursive(Page, "Grade" + i);
}

What I have tried:

i tried various suggestions from the google.