render control runtime

protected override void Render(HtmlTextWriter writer)
{
Control objCtrl = default(Control);
TextBox objTextbox = new TextBox();

writer.RenderBeginTag(HtmlTextWriterTag.Table);
writer.AddStyleAttribute(HtmlTextWriterStyle.BorderWidth, "5px");
writer.RenderBeginTag(HtmlTextWriterTag.Tr);
writer.RenderBeginTag(HtmlTextWriterTag.Td);
objCtrl = LoadControl("../uscSPCalendar.ascx");
objTextbox.ID = "txt1";
//objTextbox.RenderControl(writer);ถ้าต้องการวาด control ก่อน render
base.Controls.Add(objCtrl);
base.Controls.Add(objTextbox);
base.Render(writer);
writer.RenderEndTag();//td
writer.RenderEndTag();//tr
writer.RenderEndTag();//table
}