this will help you...........
<pre lang="text">
protected void btnCode_Click(object sender, EventArgs e)
{
System.Web.UI.HtmlControls.HtmlGenericControl dynDiv =
new System.Web.UI.HtmlControls.HtmlGenericControl("DIV");
dynDiv.ID = "dynDivCode";
dynDiv.Style.Add(HtmlTextWriterStyle.BackgroundColor, "Gray");
dynDiv.Style.Add(HtmlTextWriterStyle.Height, "20px");
dynDiv.Style.Add(HtmlTextWriterStyle.Width, "300px");
dynDiv.InnerHtml = "I was created using Code Behind";
this.Controls.Add(dynDiv);
}