protected void Page_Load(object sender, EventArgs e)
    {
        if(!IsPostBack)
        {
            
            startData();
           
        }
        
    }

    //绑定初始数据
    protected void startData()
    {
        DataSet ds = new DataSet();
        UM.userName=Session["user"].ToString();
        ds = UB.users_QueryUserDetail_by_Name(UM);

        ListItem myListItem0 = new ListItem("一棉", "firDepartmentName");
        ListItem myListItem1 = new ListItem("二棉", "firDepartmentName");

        string firDepartmentName = ds.Tables[0].Rows[0]["firDepartmentName"].ToString();
        //一级部门
        if (firDepartmentName=="一棉")
        {
            //移除所有的item
            DropDownList1.Items.Clear();
            //这里把选择项“一棉”放在前面
            this.DropDownList1.Items.Add(myListItem0);
            this.DropDownList1.Items.Add(myListItem1);

        }
        else
        {
            //移除所有的item
            DropDownList1.Items.Clear();
            //这里把选择项“二棉”放在前面
            this.DropDownList1.Items.Add(myListItem1);
            this.DropDownList1.Items.Add(myListItem0);
        }

        //二级部门
        string secDepartmentName = ds.Tables[0].Rows[0]["secDepartmentName"].ToString();
        DropDownList2.Items.Add(secDepartmentName);
    }

    //动态绑定二级部门数据
    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        //清除DropDownList2原来的item
        DropDownList2.Items.Clear();

        string FirDeparName = DropDownList1.SelectedItem.Text;
        DataSet ds = SDB.secDepartment_Query_by_FirDeparName_dataset(FirDeparName);

        DropDownList2.DataSource = ds;
        DropDownList2.DataValueField= "secDepartmentName";//绑定DropDownList2的DataValueField属性
        DropDownList2.DataTextField = "secDepartmentName"; //绑定DropDownList2的DataTextField属性

        DropDownList2.DataBind();
    }