title: Multiple controls with the same ID '' were found. FindControl requires that controls have unique IDs
body: <p><strong>update:</strong></p>
  
  <p>here is what i observed:</p>
  
  <pre><code>if i get    org.Registrations.Count = 1 then 
      txtBox.ID   "_registration0_0"  string
  ....
  ....
  </code></pre>
  
  <p>if i get org.Registrations.Count = 2 then its act strange</p>
  
  <pre><code>txtBox.ID   "_registration2_0"  
  txtBox.ID   "_registration2_1"
  
  
  after that i starts again with _registration2_0
  </code></pre>
  
  <p>ps: i dont have problem if the count = 1 </p>
  
  <p><strong>end update</strong></p>
  
  <p>the error messages clearly says that i am trying to have duplicate id but below is where i am creating dynamic textbox, do you see whats wrong in my code? </p>
  
  <pre><code>protected void gv_RowCreated(object sender, GridViewRowEventArgs e)
  {
     Students org = (namespace.Students )(e.Row.DataItem);
  
     foreach (Registration reg in org.Registrations)
     {
        int _count = org.Registrations.Count;
        for (int rowId = 0; rowId &lt; _count; rowId++)
        {
           TextBox txtBox = new TextBox();
           txtBox.ID = "_registration" + e.Row.RowIndex + "_" + rowId;
           txtBox.Text = reg.Name;
           e.Row.Cells[7].Controls.Add(txtBox);
       }
     }
  }
  </code></pre>