CalculationDescriptorAttribute

/* ------------------------------------------------
 * Describes the Entity class for: Order_Detail
 * Classes:
 *    Order_Detail - Entity class. Edit it for validation and to customize metadata at runtime
 *    Order_DetailMetadata - Entity Metadata class. It contains the DataAnnotations.
 *    Order_DetailDAO - BLD DataAccessObject format version of a Data Access Object.
 *    
 * Requires .net 4.0 and these references:
 *    System.ComponentModel.DataAnnotations
 *    PeterBlum.DES
 *    PeterBlum.DES.DataAnnotations
 * Generated: 7/8/2011 4:19:12 PM
 * ------------------------------------------------*/
using System;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.Collections.Generic;
using PeterBlum.DES.DAO.Attributes;
using PeterBlum.DES.DAO.EntityDAO;
using PeterBlum.DES.DAO.EntityFilters;
using PeterBlum.DES.DAO;
// Some members of this namespace have identical names to those in System.ComponentModel.DataAnnotations
// making it easy to switch from one to the other by adding the "DESDA." prefix
using DESDA = PeterBlum.DES.DataAnnotations;

namespace PeterBlum.WithDataAnnotations
{
   // --- ENTITY CLASS --------------------------------------------------
   /// <summary>
   /// Entity class. Edit it for validation and to customize metadata at runtime
   /// </summary>
   [EntityDAOType(typeof(Order_DetailDAO))]
   [MetadataType(typeof(Order_DetailMetadata))]
   public partial class Order_Detail
   {
/// <summary>
/// Calculated field showing the price after discount is applied.
/// The CalculationDescriptorAttribute lets the UI know how the calculation is
/// created so it can provide an interactive calculation as the user edits.
/// </summary>
      [DESDA.CurrencyDataType()]
      [DESDA.DisplayName("Order Price", ShortDisplayName="Price")]
      [DESDA.ScaffoldColumn("Discount")]
      [DESDA.CalculationDescriptor("(UnitPrice * Quantity) * (1.0 - Discount)")]
      public decimal OrderPrice
      {
         get
         {
            return (UnitPrice * Quantity) * Convert.ToDecimal(1.0 - Discount);
         }
      }

   }  // class Order_Detail

   // --- ENTITY METADATA --------------------------------------------------
   /// <summary>
   /// Entity Metadata class.
   /// Companion to the Order_Detail Entity class that contains the DataAnnotations
   /// on properties with the same names as those in the actual Entity class.
   /// These properties do not require their types to match those in the Entity class.
   /// An Entity Metadata class allows the Entity class to be regenerated without
   /// overwriting DataAnnotations.
   /// </summary>
   [DESDA.DisplayName("Order details")]
   [DESDA.TableRestriction("Admin", DESDA.DenyAccess.None)]
   [DESDA.TableRestriction("Customer", DESDA.DenyAccess.Edit | DESDA.DenyAccess.Delete | DESDA.DenyAccess.Insert)]
   [ScaffoldTable(false)]
   public class Order_DetailMetadata
   {
      [DESDA.CurrencyDataType(AllowNegatives=false)]
      [DESDA.DisplayName("Unit Price")]
      public object UnitPrice { get; set; }

      [DESDA.IntegerDataType(AllowNegatives=false)]
      public object Quantity { get; set; }

/// <summary>
/// The Discount value is a percentage which is normally represented as 
/// an integer with 0 to 100, but in this case, its a decimal with
/// a range of 0 to 1. Make sure calculations are aware of this. (See Order_Detail.OrderPrice).
/// </summary>
      [DESDA.DecimalDataType()]
      [DESDA.Range(0.0, 1.0)]
      public object Discount { get; set; }

   }  // class Order_DetailMetadata

   // --- BLD DATAACCESSOBJECT  --------------------------------------------------
   /// <summary>
   /// BLD DataAccessObject class for the Order_Detail Entity class.
   /// It provides CRUD actions. The parent class already has default
   /// methods for Update(), Insert(), Delete() and several queries.
   /// </summary>
   /// <remarks>
   /// <para>For documentation, see the BLD DataAccessObject section of the Business Logic User's Guide.</para>
   /// </remarks>
   [TableName("Order Details")]
   public class Order_DetailDAO : LINQtoSQLEntityDAO<Order_Detail>
   {
      public Order_DetailDAO() : base(typeof(NorthWindDataContext)) { }
      public Order_DetailDAO(object pDataContext) : base(pDataContext) { }

/// <summary>
/// The Order Details table has two primary keys. The default SelectOne method
/// only takes one primary key. SelectOne is the default method name used
/// to retrieve a single record.
/// </summary>
/// <param name="pOrderID"></param>
/// <param name="pProductID"></param>
/// <param name="pArgs"></param>
/// <returns></returns>
      [DataObjectMethod(DataObjectMethodType.Select)]
      [SelectArgs(Filters=false, SortExpression=false, Paging=false)]
      [SelectMethodParameter(ActualName="orderID", AliasNames="Order",
         Description="The primary key to a record in the Orders table.")]
      [SelectMethodParameter(ActualName="productID", AliasNames="Product",
         Description="The primary key to a record in the Products table.")]
      public IEnumerable<Order_Detail> SelectOne(int orderID, int productID, SelectArgs args)
      {
         args.AddEntityFilter(new CompareToValueEntityFilter("OrderID", DES.ConditionOperator.Equal, orderID));
         args.AddEntityFilter(new CompareToValueEntityFilter("ProductID", DES.ConditionOperator.Equal, productID));

         return ExecuteSelectCommand(args);
      }

   }  // class Order_DetailDAO

}