cid = Int32.Parse(Request.Params["cid"].ToString());

cid 没有传参数时候 就错误.,传了cid参数 就正常了  为什么呢
我想不传CID参数和  传都可以这样的

public partial class standards_index : System.Web.UI.Page
{
    public int cid = 2;
    int teid;
    DataCommonProvider dp = DataCommonProvider.Instance();
    protected void Page_Load(object sender, EventArgs e)
    {
            cid = Int32.Parse(Request.Params["cid"].ToString());
        if (!IsPostBack)
        {
            DataBind();
            StandsDataBind();
        }
        if (cid ==2)
        {
            teid = 43;
        }
        else
        {
            teid = 44;
        }
    }