请选择主题 默认主题 红色主题 蓝色主题 protected void Page_PreInit(object sender, EventArgs e) { this.Theme =Request .__________ ["theme"]; } protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) { string themestyle = DropDownList1.SelectedItem.Text; __________ (__________) { case "默认主题": Response.Redirect("Default.aspx?theme=common"); break; case "红色主题": Response.Redirect("Default.aspx?theme=theme1"); break; case "蓝色主题": Response.Redirect("Default.aspx?theme=theme2"); break; } }