protected void Page_Load(object sender, EventArgs e)
    {
        //Database db = new Database();
        //string sql = "select id,field_code from field_baseinfo";
        //FarmlandManageGridView.DataSource = db.GetReader(sql);
        //FarmlandManageGridView.DataBind();
        //db.Close();
        FreshGridViewWithData();

    }

    //刷新GridView
    private void GridViewDataBind()
    {
        FarmlandManageGridView.DataSource = buildDisplayTable();
        FarmlandManageGridView.DataBind();
    }

    private void FreshGridViewWithData()
    {
        long danwei_id = DataTypeUtil.ParseLong(this.unitDropDownList.SelectedValue.ToString());
        int theYear = DataTypeUtil.ParseInt(this.yearDropDownList.SelectedItem.ToString());
        selectedlist = service.FindByDanweiAndYear(danwei_id, theYear);
        GridViewDataBind();
    }

    private DataTable buildDisplayTable()
    {
        var result = selectedlist.Select(p => new
        {
            id = p.id,
            field_code = p.crop_manageinfo.field_baseInfo.field_code,
            cropname = p.crop_manageinfo.breeds.crop.cropname,
            breed_name = p.crop_manageinfo.breeds.breed_name,
            seed_date = p.seed_date.ToShortDateString(),
            pumo_type = p.pumo_type,
            guangai_type = p.guangai_type
        });
        DataTable table = DataSetLinqOperators.CopyToDataTable(result);
        return table;
    }