Silverlight + DomainService 简易框架之二完成查询操作

使用Silverlight + DomainService进行开发时我们可以在Silverlight项目中创建一个BLL层用于Silverlight调用如下图所示

要完成数据查询功能在Sliverlight项目中做了这么几项工作

1.定义查询处理委托

public delegate void SelectHander<T>(IEnumerable<T> data);

2.编写BLL代码

我这里写了一个DB类用于处理DomainService对象,代码如下

    public class DB
    {
        private static DomainService1 _db;
        public static DomainService1 db
        {
            get
            {
                if (_db == null) _db = new DomainService1();
                return _db;
            }
        }
    }

2.1普通全查功能

    public class RoleBLL
    {
        public static void FindAll(SelectHander<UserRoles> sh)
        {
            var db = DB.db;
            var m = db.Load<UserRoles>(db.GetUserRolesQuery());
            m.Completed += (a, b) =>
            {
                sh(m.Entities);                
            };
        }
    }

2.2如果要完成带条件查询需要在Web服务端进行处理

2.2.1 修改原来的

public  class DomainService1 : LinqToEntitiesDomainService<MyBookShopEntities>

改为

public partial class DomainService1 : LinqToEntitiesDomainService<MyBookShopEntities>

这样自己就可以再写一个局部类来扩充DomainService1的代码

    public partial class DomainService1
    {
        public IQueryable<UserRoles> GetUserRolesByName(string name)
        {
            return this.ObjectContext.UserRoles.Where(r => r.Name.StartsWith(name));
        }
    }

2.2.2这样在Silverlight端的RoleBLL就可以调用服务端的查询,Silverlight端代码如下:

    public class RoleBLL
    {
        public static void FindAll(SelectHander<UserRoles> sh)
        {
            var db = DB.db;
            var m = db.Load<UserRoles>(db.GetUserRolesQuery());
            m.Completed += (a, b) =>{sh(m.Entities);};
        }
        public static void FindAllByName(string name, SelectHander<UserRoles> sh)
        {
            var db = DB.db;
            var m = db.Load<UserRoles>(db.GetUserRolesByNameQuery(name));
            m.Completed += (a, b) => { sh(m.Entities); };
        }
    }

3.Silverlight表示层端调用

        public MainPage()
        {
            InitializeComponent();
            this.Loaded += new RoutedEventHandler(MainPage_Loaded);
        }

        void MainPage_Loaded(object sender, RoutedEventArgs e)
        {
            RoleBLL.FindAll(datas => { userRolesDataGrid.ItemsSource = datas; });
        }

效果:

条件查询代码:

        private void btnQuery_Click(object sender, RoutedEventArgs e)
        {
            RoleBLL.FindAllByName(txtName.Text, datas => { userRolesDataGrid.ItemsSource = datas; });
        }

效果: