WCF RIA Services 快速上手

WCF RIA Services 简化开发RIA n-tier 解决方案。让你快速构建Silverlight n-tier应用程序客户端与服务端的通信。下面我们来看一张图：

下面我们来构建一个简单的DEMO:

首先，下载Silverlight 4 Tools for Visual Studio 2010 ,建一个Silverlight project:

接下弹出对话框，记得Enable WCF RIA Services:

建立DEMO的表，并插入几条数据：

CREATE TABLE [dbo].[tblItem](
    [ItemNumber] INT NOT NULL,
    [ItemDescription] [varchar](50) NULL,
    [Quantity] [int] NULL
CONSTRAINT [PK_tblItem] PRIMARY KEY CLUSTERED
(
    [ItemNumber] ASC )
)

INSERT INTO [tblItem]
           ([ItemNumber]
           ,[ItemDescription]
           ,[Quantity])
VALUES ('1','Item Name1',1),
       ('2','Item Name2',2),
       ('3','Item Name3',3),
       ('4','Item Name4',4),
       ('5','Item Name5',5),
       ('6','Item Name6',6)

接着我们对这个TABLE建EF4 DATA MODEL，这里我们将不再深入，待建立好后，创建DomainService:

然后选择那个Entities:

接下将会生成一个Service的文件：

namespace RIAServices.Web
{
    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.ComponentModel.DataAnnotations;
    using System.Data;
    using System.Linq;
    using System.ServiceModel.DomainServices.EntityFramework;
    using System.ServiceModel.DomainServices.Hosting;
    using System.ServiceModel.DomainServices.Server;


    // Implements application logic using the BirdLLEntities context.
    // TODO: Add your application logic to these methods or in additional methods.
    // TODO: Wire up authentication (Windows/ASP.NET Forms) and uncomment the following to disable anonymous access
    // Also consider adding roles to restrict access as appropriate.
    // [RequiresAuthentication]
    [EnableClientAccess()]
    public class ItemService : LinqToEntitiesDomainService<BirdLLEntities>
    {

        // TODO:
        // Consider constraining the results of your query method.  If you need additional input you can
        // add parameters to this method or create additional query methods with different names.
        // To support paging you will need to add ordering to the 'tblItems' query.
        public IQueryable<tblItem> GetTblItems()
        {
            return this.ObjectContext.tblItems;
        }

        public void InsertTblItem(tblItem tblItem)
        {
            if ((tblItem.EntityState != EntityState.Detached))
            {
                this.ObjectContext.ObjectStateManager.ChangeObjectState(tblItem, EntityState.Added);
            }
            else
            {
                this.ObjectContext.tblItems.AddObject(tblItem);
            }
        }

        public void UpdateTblItem(tblItem currenttblItem)
        {
            this.ObjectContext.tblItems.AttachAsModified(currenttblItem, this.ChangeSet.GetOriginal(currenttblItem));
        }

        public void DeleteTblItem(tblItem tblItem)
        {
            if ((tblItem.EntityState == EntityState.Detached))
            {
                this.ObjectContext.tblItems.Attach(tblItem);
            }
            this.ObjectContext.tblItems.DeleteObject(tblItem);
        }

        /// <summary>
        /// Gets the TBL items by item number.
        /// </summary>
        /// <param name="itemnumber">The itemnumber.</param>
        /// <returns></returns>
        public IQueryable<tblItem> GetTblItemsByItemNumber(int itemnumber)
        {
            return this.ObjectContext.tblItems.Where(i => i.ItemNumber == itemnumber);
        }
    }

另一个是Metadata :

 

namespace RIAServices.Web
{
    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.ComponentModel.DataAnnotations;
    using System.Linq;
    using System.ServiceModel.DomainServices.Hosting;
    using System.ServiceModel.DomainServices.Server;

    // The MetadataTypeAttribute identifies tblItemMetadata as the class
    // that carries additional metadata for the tblItem class.
    [MetadataTypeAttribute(typeof(tblItem.tblItemMetadata))]
    public partial class tblItem
    {

        // This class allows you to attach custom attributes to properties
        // of the tblItem class.
        //
        // For example, the following marks the Xyz property as a
        // required property and specifies the format for valid values:
        //    [Required]
        //    [RegularExpression("[A-Z][A-Za-z0-9]*")]
        //    [StringLength(32)]
        //    public string Xyz { get; set; }
        internal sealed class tblItemMetadata
        {

            // Metadata classes are not meant to be instantiated.
            private tblItemMetadata()
            {
            }

            public string ItemDescription { get; set; }

            public int ItemNumber { get; set; }

            public Nullable<int> Quantity { get; set; }
        }
    }
}

然后打开Data—>Show Data Source，如下图：

然后打开另一个Project中Mainpage.xaml，我们之前应用生成这样的XMAL:

<UserControl x:Class="RIAServices.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="536" d:DesignWidth="463" xmlns:riaControls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.DomainServices" xmlns:my="clr-namespace:RIAServices.Web" xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk">

    <Grid x:Name="LayoutRoot" Background="White" Height="536" Width="463">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="140*" />
            <ColumnDefinition Width="47*" />
            <ColumnDefinition Width="405*" />
        </Grid.ColumnDefinitions>
        <riaControls:DomainDataSource AutoLoad="False" d:DesignData="{d:DesignInstance my:tblItem, CreateList=true}" Height="0" LoadedData="tblItemDomainDataSource_LoadedData" Name="tblItemDomainDataSource" QueryName="GetTblItemsQuery" Width="0" Margin="0,0,140,393">
            <riaControls:DomainDataSource.DomainContext>
                <my:ItemContext />
            </riaControls:DomainDataSource.DomainContext>
        </riaControls:DomainDataSource>
        <sdk:DataGrid AutoGenerateColumns="False" Height="181" HorizontalAlignment="Left" ItemsSource="{Binding ElementName=tblItemDomainDataSource, Path=Data}" Name="tblItemDataGrid" RowDetailsVisibilityMode="VisibleWhenSelected" VerticalAlignment="Top" Width="400" Margin="0,58,0,0" Grid.ColumnSpan="3">
            <sdk:DataGrid.Columns>
                <sdk:DataGridTextColumn x:Name="itemDescriptionColumn" Binding="{Binding Path=ItemDescription}" Header="Item Description" Width="SizeToHeader" />
                <sdk:DataGridTextColumn x:Name="itemNumberColumn" Binding="{Binding Path=ItemNumber, Mode=OneWay}" Header="Item Number" IsReadOnly="True" Width="SizeToHeader" />
                <sdk:DataGridTextColumn x:Name="quantityColumn" Binding="{Binding Path=Quantity}" Header="Quantity" Width="SizeToHeader" />
            </sdk:DataGrid.Columns>
        </sdk:DataGrid>
        <Button Content="Query" Height="23" HorizontalAlignment="Left" Margin="171,12,0,0" Name="btnquery" VerticalAlignment="Top" Width="75" Click="btnquery_Click" Grid.Column="2" />
        <TextBox Height="23" HorizontalAlignment="Left" Margin="1,12,0,0" Name="txtItemNumber" VerticalAlignment="Top" Width="120" Grid.ColumnSpan="2" />
        <sdk:DataGrid AutoGenerateColumns="False" Height="179" HorizontalAlignment="Left" ItemsSource="{Binding ElementName=tblItemDomainDataSource, Path=Data}" Margin="1,320,0,0" Name="dataGrid1" RowDetailsVisibilityMode="VisibleWhenSelected" VerticalAlignment="Top" Width="400" Grid.ColumnSpan="3">
            <sdk:DataGrid.Columns>
                <sdk:DataGridTextColumn x:Name="dataGridTextColumn1" Binding="{Binding Path=ItemDescription}" Header="Item Description" Width="SizeToHeader" />
                <sdk:DataGridTextColumn x:Name="dataGridTextColumn2" Binding="{Binding Path=ItemNumber, Mode=OneWay}" Header="Item Number" IsReadOnly="True" Width="SizeToHeader" />
                <sdk:DataGridTextColumn x:Name="dataGridTextColumn3" Binding="{Binding Path=Quantity}" Header="Quantity" Width="SizeToHeader" />
            </sdk:DataGrid.Columns>
        </sdk:DataGrid>
        <sdk:Label Grid.ColumnSpan="3" Height="21" HorizontalAlignment="Left" Margin="1,281,0,0" Name="label1" VerticalAlignment="Top" Width="189" Content="CustomerService from ADO.NET" />
    </Grid>
</UserControl>

为了对比我们建立另一个自定义DomainService, 也需要建立一个Entity:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.ServiceModel.DomainServices.Hosting;
using System.ServiceModel.DomainServices.Server;

namespace RIAServices.Web
{
    public class Item
    {
        [Key]
        public int ItemNumber { get; set; }
        public string ItemDescription { get; set; }
        public Nullable<int> Quantity { get; set; }
    }
}

CustomerDomainService，里面我们使用原生态的ADO.NET进行数据访问，你也可以替代成你自己的数据Provider.

    [EnableClientAccess()]
    public class CustomerDomainService : DomainService
    {
        public List<Item> GetItemsFromDatabase()
        {
            SqlConnection sqlConnection = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["MainDb"].ToString());
            DataSet objSet = new DataSet();
            SqlCommand sqlCommand = new SqlCommand();
            sqlCommand.Connection = sqlConnection;
            sqlCommand.CommandText = "Select * FROM tblItem";
            SqlDataAdapter sqlDataAdapter = new SqlDataAdapter();
            sqlDataAdapter.SelectCommand = sqlCommand;
            sqlDataAdapter.Fill(objSet);

            List<Item> lstResult = new List<Item>();
            Item objEmployee;

            if (objSet.Tables.Count > 0)
            {
                foreach (DataRow dr in objSet.Tables[0].Rows)
                {
                    objEmployee = new Item();
                    objEmployee.Quantity = Convert.ToInt32(dr["Quantity"]);
                    objEmployee.ItemDescription = dr["ItemDescription"].ToString();
                    objEmployee.ItemNumber = Convert.ToInt32(dr["ItemNumber"]);
                    lstResult.Add(objEmployee);
                }
            }
            return lstResult;
        }
    }

最后我们来看MainPage.xaml.cs 的代码：

   public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();

            var itemContext = new ItemContext();
            tblItemDataGrid.ItemsSource = itemContext.tblItems;
            EntityQuery<tblItem> s = itemContext.GetTblItemsQuery();
            LoadOperation<tblItem> op = itemContext.Load(s);

            //Use another domain service
            var customerservice = new CustomerDomainContext();
            dataGrid1.ItemsSource = customerservice.Items;
            EntityQuery<Item> s2 = customerservice.GetItemsFromDatabaseQuery();
            LoadOperation<Item> op2 = customerservice.Load(s2);

        }

        private void tblItemDomainDataSource_LoadedData(object sender, System.Windows.Controls.LoadedDataEventArgs e)
        {
            if (e.HasError)
            {
                System.Windows.MessageBox.Show(e.Error.ToString(), "Load Error", System.Windows.MessageBoxButton.OK);
                e.MarkErrorAsHandled();
            }
        }

        /// <summary>
        /// Handles the Click event of the btnquery control.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="System.Windows.RoutedEventArgs"/> instance containing the event data.</param>
        private void btnquery_Click(object sender, RoutedEventArgs e)
        {
            var tt = new ItemContext();
            tblItemDataGrid.ItemsSource = tt.tblItems;
            EntityQuery<tblItem> s = tt.GetTblItemsByItemNumberQuery(txtItemNumber.Text == "" ? 0 : Convert.ToInt32(txtItemNumber.Text));
            LoadOperation<tblItem> op = tt.Load(s);
        }

    }

这里我们禁用了默认SilverLight DataGrid的自动绑定，在InitializeComponent方法后增加了代码绑定。btnquery_Click方法对应的是UI上那个Button的Click事件，用来做数据查询。
另一个要注意是ItemService中的GetTblItemsByItemNumber方法是后面加入的，其它方法是自动生成的。最后F5运动后效果是：

简单查询的结果:

这个后面访问了WCF Service地址是:

http://localhost:54934/Services/RIAServices-Web-ItemService.svc

通过Monitor我们看到GetItemsFromDatabase方法返回的数据是:

@GetItemsFromDatabaseResponsehttp://tempuri.org/@GetItemsFromDatabaseResult    aDomainServices    i)http://www.w3.org/2001/XMLSchema-instance^
TotalCount?^ RootResults    b7http://schemas.datacontract.org/2004/07/RIAServices.Web_Item_ItemDescription?Item Name1_
ItemNumber僟Quantity?_Item_ItemDescription?Item Name2_
ItemNumber?_Quantity?_Item_ItemDescription?Item Name3_
ItemNumber?_Quantity?_Item_ItemDescription?Item Name4_
ItemNumber?_Quantity?_Item_ItemDescription?Item Name5_
ItemNumber?_Quantity?_Item_ItemDescription?Item Name6_
ItemNumber?_Quantity?

这是WCF RIA Service默认的数据格式。有时间将在以后解析它们。希望对您的开发有帮助。

作者：Petter Liu
出处：http://www.cnblogs.com/wintersun/
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该文章也同时发布在我的独立博客中-Petter Liu Blog。