How to handle dynamic buttons?

I created buttons dynamically with a loop. Into a table and it was successfully added.
Here's a part of my code.

PHP Code:

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for (int i = 0; i < 6; i++)
{
            Button btn = new Button();
            btn.Text = "Available";
            btn.ID = "btn" + i;
            btn.Click += new System.EventHandler(btn_Click);
            tc.Controls.Add(btn);
}

public void btn_Click(object sender, System.EventArgs e)
{
        Button currentButton = (Button)sender;
        string ID = currentButton.ID;
        switch(ID)
        {
            case "btn1": subjectID = subjectIDs[0]; break;
            case "btn2": subjectID = subjectIDs[1]; break;
            case "btn3": subjectID = subjectIDs[2]; break;
            case "btn4": subjectID = subjectIDs[3]; break;
            case "btn5": subjectID = subjectIDs[4]; break;
            case "btn6": subjectID = subjectIDs[5]; break;
        }
} 


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But when I click the buttons that were created, the event isn't firing.
Is my button handler correct?