// BusinessDataServiceHelper 查询示例
// 适用插件：Form/Operation/Validator/Report
// 依赖 API：BusinessDataServiceHelper, QFilter
// 相关检查：推荐避免直接猜测字段 key，建议通过元数据核实
using Kingdee.BOS;
using Kingdee.BOS.Core.CommonFilter;
using Kingdee.BOS.Orm.DataEntity;
using Kingdee.BOS.ServiceHelper;

public class QuerySample
{
    private Context ctx;

    public void DemonstrateQuery()
    {
        string formId = "PUR_POOrder";

        // 按主键查询单个实体
        long primaryKey = 100001;
        DynamicObject entity = BusinessDataServiceHelper.LoadSingle(ctx, primaryKey, formId);

        // 按 QFilter 条件查询多个实体
        QFilter filter = new QFilter("billno", "=", "PO-001");
        DynamicObject[] entities = BusinessDataServiceHelper.Load(ctx, formId, new QFilter[] { filter });

        // 查询指定字段（优化性能，只加载需要的字段）
        string[] selectFields = new string[] { "id", "billno", "date", "amount" };
        DynamicObject[] partialEntities = BusinessDataServiceHelper.Load(
            ctx, formId, selectFields, new QFilter[] { filter }
        );

        // 从实体取值
        string billNo = entity["billno"] as string;
        decimal amount = Convert.ToDecimal(entity["amount"] ?? 0);

        // 基础资料字段取值（返回 DynamicObject）
        DynamicObject supplier = entity["supplier"] as DynamicObject;
        if (supplier != null)
        {
            long supplierId = Convert.ToInt64(supplier["Id"]);
            string supplierName = supplier["Name"] as string;
        }
    }
}