Button inside server control doesn't render onclick="__doPostback"
<p>I'm developing a Asp.net server control (inherited from DataBoundControl) and I have just one button inside it for now which is created in CreateChildControls override. Even though this button have Click event assigned in rendered page the button don't have onclick event with __doPostback or something similar. Am I missing something? </p>

<pre><code>public class FileList : DataBoundControl, INamingContainer
{
    protected override void CreateChildControls()
    {
        // Add button
        btnAddFile = new System.Web.UI.WebControls.Button();
        btnAddFile.ID = "btnAddFile";
        btnAddFile.Click += btnAddFile_Click;
        btnAddFile.CssClass = "Button";
        btnAddFile.CausesValidation = false;
        Controls.Add(btnAddFile);
    }

    void btnAddFile_Click(object sender, EventArgs e)
    {
        throw new NotImplementedException();
    }
}
</code></pre>
