MOSS 2010:Visual Studio 2010开发体验（25）——编写自定义的BCS连接器（续）

上一篇我讲解到了如何在Visual Studio 2010中编写自定义的BCS连接器来实现更加灵活的应用程序集成。在那篇文章，我主要讲解了有关的概念，并且做了一个最简单的模型，发布之后能够使用它。

这一篇，我们继续来实现一个更加有现实意义的 BCS 连接器。我们需要读取的数据仍然是有关员工信息的。

我们希望员工实体拥有如下的信息

ID
FirstName
LastName
Age

【提示】通过跟随本文做练习，你将学会如何设计一个自己的业务实体模型。

【注意】不要小看这个步骤，我之前就提到过，自定义BCS模型这个小工具其实还有值得改进的地方。目前的情况是一不小心就会出错。所以，最好按照我的步骤来做练习。这个步骤是我总结出来的最佳实践，你可以先做完练习，然后对某些步骤的细节做一些进一步的学习

1. 创建一个空白SharePoint项目

2. 添加一个BDC模型

3. 修改业务实体（Entity）

所谓实体就是在BDC服务中交换的数据格式。例如我们要处理员工数据，这就是一个实体。项目模板默认生成的实体类型如下（Entity1.cs)

将代码修改为下面这样

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace BDC.Northwind.EmployeeModel
{
    /// <summary>
    /// This class contains the properties for Entity1. The properties keep the data for Entity1.
    /// If you want to rename the class, don't forget to rename the entity in the model xml as well.
    /// </summary>
    public partial class Employee
    {
        //TODO: Implement additional properties here. The property Message is just a sample how a property could look like.
        public int EmployeeID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int Age { get; set; }
    }
}

4. 修改服务类型(Service)

实体只是数据,但谁来接受请求并且处理,然后返回数据呢?这就是服务的概念. 默认生成的那个 Entity1Service.cs就是服务所在的文件。它现在看起来是下面这样的

将代码修改如下

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace BDC.Northwind.EmployeeModel
{
    /// <summary>
    /// All the methods for retrieving, updating and deleting data are implemented in this class file.
    /// The samples below show the finder and specific finder method for Entity1.
    /// </summary>
    public class EmployeeService
    {

        static List<Employee> GetEmployees()
        {
            return new List<Employee>(){
                new Employee(){
                    EmployeeID=1,
                    FirstName="ares",
                    LastName="chen",
                    Age=20
                },
                new Employee(){
                    EmployeeID=2,
                    FirstName="bill",
                    LastName="gates",
                    Age=20
                },
                new Employee(){
                    EmployeeID=3,
                    FirstName="steve",
                    LastName="ballmer",
                    Age=20
                }
            };
        }

        /// <summary>
        /// This is a sample specific finder method for Entity1.
        /// If you want to delete or rename the method think about changing the xml in the BDC model file as well.
        /// </summary>
        /// <param name="id"></param>
        /// <returns>Entity1</returns>
        public static Employee ReadItem(int id)
        {
            return GetEmployees().FirstOrDefault(e => e.EmployeeID == id);
        }
        /// <summary>
        /// This is a sample finder method for Entity1.
        /// If you want to delete or rename the method think about changing the xml in the BDC model file as well.
        /// </summary>
        /// <returns>IEnumerable of Entities</returns>
        public static IEnumerable<Employee> ReadList()
        {
            return GetEmployees();
        }
    }
}