protected void btnSearch_Click(object sender, EventArgs e) { List<Book> list = new List<Book>(); String keyword = txtKeyword.Text; String type = SearchCondition_ddl.Text; if (type == "Title") { list = sc.searchByTitle(keyword); } else if (type == "Author") { list = sc.searchByAuthor(keyword); } try { this.GridView1.DataSource = list; this.GridView1.DataBind(); } catch (Exception ex) { string errormsg = string.Format("<script>Error:{0}</script>", ex.Message); Response.Write(errormsg); } }