protected void btn22_Click(object sender, EventArgs e) { // Clear all content output from the buffer stream Response.ClearContent(); // Specify the default file name using "content-disposition" RESPONSE header Response.AppendHeader("content-disposition", "attachment; filename=pic.xls"); // Set excel as the HTTP MIME type Response.ContentType = "application/excel"; // Create an instance of stringWriter for writing information to a string System.IO.StringWriter stringWriter22 = new System.IO.StringWriter(); // Create an instance of HtmlTextWriter class for writing markup // characters and text to an ASP.NET server control output stream HtmlTextWriter htw22 = new HtmlTextWriter(stringWriter22); GridView22.RenderControl(htw22); Response.Write(stringWriter22.ToString()); Response.End(); }