aspx后台页面添加服务器控件

System.Text.StringBuilder stringBuilder = new System.Text.StringBuilder();

System.IO.StringWriter stringWriter = new System.IO.StringWriter(stringBuilder);

System.Web.UI.HtmlTextWriter htmlTextWriter = new System.Web.UI.HtmlTextWriter(stringWriter);      

       
TextBox tb = new TextBox();

tb.ID = "t1";

tb.Text = "text1";

tb.Width = 1000;

tb.RenderControl(htmlTextWriter);

string a = stringBuilder.ToString();