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silverlight 发布时间：2022-05-04 发布网站：大佬教程 code.js-code.com

大佬教程收集整理的这篇文章主要介绍了Silverlight同步(Synchronous)调用WCF服务，大佬教程大佬觉得挺不错的，现在分享给大家，也给大家做个参考。

概述

　　Silverlight的RIA应用中访问远端的Webservice或WCF服务，都是通过异步线程模式调用的。在某些情况下我们的调用是需要同步进行，虽然Silverlight没有内置同步线程模式调用远端服务接口，但是我们可以通过多线程的处理来伪装出同步调用的实现。在.NET Framework的多线程编程中提供了丰富的线程接口，其中autoResetEvent和ManualResetEvent在

一、定义WCF服务

　　为了演示同步调用WCF服务的实现，提供一个简单的WCF服务接口，完成返回一本图书基本信息，WCF服务接口定义如下：

@H_772_37@[serviceContract]
public @H_772_37@ interface @H_772_37@ IDataservice
{
    [OperationContract]
    Book GetBook();
}

public @H_772_37@ class @H_772_37@ Book
{
     public @H_772_37@ int @H_772_37@ ID { get @H_772_37@; set @H_772_37@; }
     public @H_772_37@ String @H_772_37@ NAME { get @H_772_37@; set @H_772_37@; }
     public @H_772_37@ String @H_772_37@ Author { get @H_772_37@; set @H_772_37@; }
     public @H_772_37@ double @H_772_37@ Price { get @H_772_37@; set @H_772_37@; }
}

　　接口提供一个返回图书基本信息的方法，包括图书编好，图书名，图书作者以及图书价格。接口具体的实现如下代码：

public @H_772_37@ class @H_772_37@ Dataservice : IDataservice
{
     public @H_772_37@ Book GetBook()
    {
         return @H_772_37@ new @H_772_37@ Book
        {
            ID @H_772_37@= @H_772_37@ @H_502_163@1001 @H_772_37@,
            NAME @H_772_37@= @H_772_37@ " 《三国演义》 " @H_772_37@,
            Author @H_772_37@= @H_772_37@ " 罗贯中 " @H_772_37@,
            Price @H_772_37@= @H_772_37@ @H_502_163@89.50 @H_772_37@
        };
    }
}

　　如上提供可正常运行的WCF服务接口，在需要调用接口的地方通过WEB引用既可生成该服务的客户端代理对象。

二、基于MVVM模式的视图模型

　　MVVM模式的核心为INotifyPropertyChanged接口，对于实体模型对象和UI控件元素间提供了完善的同步更新特性。为了方便界面元素同步更新，这里引入了MVVP模式的简单应用。

public @H_772_37@ class @H_772_37@ viewmodelBase : INotifyPropertyChanged
{
     public @H_772_37@ event @H_772_37@ PropertyChangedEventHandler PropertyChanged;

     protected @H_772_37@ void @H_772_37@ raisePropertyChangedEvent( String @H_772_37@ propertyName)
    {
        var handler @H_772_37@= @H_772_37@ PropertyChanged;
         if @H_772_37@ (handler @H_772_37@!= @H_772_37@ null @H_772_37@)
            handler( this @H_772_37@, new @H_772_37@ PropertyChangedEventArgs(propertyName));
    }
}

　　还需要对应于服务接口中的Book对象定义一个 viewmodel对象，详细如下代码所示：

public @H_772_37@ class @H_772_37@ Bookviewmodel : viewmodelBase
{
     private @H_772_37@ int @H_772_37@ iD;
     /// <sumMary>
     /// 图书ID
     /// </sumMary>
@H_772_37@     public @H_772_37@ int @H_772_37@ ID
    {
         get @H_772_37@ { return @H_772_37@ iD; }
         set @H_772_37@
        {
            iD @H_772_37@= @H_772_37@ value;
            raisePropertyChangedEvent( " ID " @H_772_37@);
        }
    }

     private @H_772_37@ String @H_772_37@ NAME;
     /// <sumMary>
     /// 图书名称
     /// </sumMary>
@H_772_37@     public @H_772_37@ String @H_772_37@ NAME
    {
         get @H_772_37@ { return @H_772_37@ NAME; }
         set @H_772_37@
        {
            NAME @H_772_37@= @H_772_37@ value;
            raisePropertyChangedEvent( " Name " @H_772_37@);
        }
    }

     private @H_772_37@ String @H_772_37@ author;
     /// <sumMary>
     /// 图书作者
     /// </sumMary>
@H_772_37@     public @H_772_37@ String @H_772_37@ Author
    {
         get @H_772_37@ { return @H_772_37@ author; }
         set @H_772_37@
        {
            author @H_772_37@= @H_772_37@ value;
            raisePropertyChangedEvent( " Author " @H_772_37@);
        }
    }

     private @H_772_37@ double @H_772_37@ price;
     /// <sumMary>
     /// 图书价格
     /// </sumMary>
@H_772_37@     public @H_772_37@ double @H_772_37@ Price
    {
         get @H_772_37@ { return @H_772_37@ price; }
         set @H_772_37@
        {
            price @H_772_37@= @H_772_37@ value;
            raisePropertyChangedEvent( " Price " @H_772_37@);
        }
    }
}

三、基于AutoResetEvent的同步实现

　　利用AutoResetEvent的线程等待特性，可以折中实现Silverlight同步调用远端WCF服务。其原理就是在Silverlight发起异步调用远端WCF的时候进行线程阻塞，比记录异步调用远端WCF服务接口的完成事件，当异步调用完成后就终止线程阻塞，从而获取状态事件对象中或得调用远程接口所返回的结果。由于视图模型对象实现了INotifyPropertyChanged接口能够及时的更新界面元素，以此间接的就实现了同步方式调用。

public @H_772_37@ class @H_772_37@ AsyncCallStatus @H_772_37@< @H_772_37@T @H_772_37@> @H_772_37@
{
     public @H_772_37@ AsyncCallStatus()
    {

    }

     public @H_772_37@ T CompletedEventArgs { get @H_772_37@; set @H_772_37@; }
}

public @H_772_37@ class @H_772_37@ BookFacade
{
     private @H_772_37@ AutoResetEvent autoResetEvent @H_772_37@= @H_772_37@ new @H_772_37@ AutoResetEvent( false @H_772_37@);

     public @H_772_37@ void @H_772_37@ GetBook(Bookviewmodel viewmodel)
    {
         if @H_772_37@ (viewmodel @H_772_37@== @H_772_37@ null @H_772_37@)
        {
             throw @H_772_37@ new @H_772_37@ argumentNullException( " viewmodel " @H_772_37@, " 参数不能为空。 " @H_772_37@);
        }

        Dataservice.DataserviceClient client @H_772_37@= @H_772_37@ new @H_772_37@ Dataservice.DataserviceClient();
        client.GetBookCompleted @H_772_37@+= @H_772_37@ client_GetBookCompleted;

        var status @H_772_37@= @H_772_37@ new @H_772_37@ AsyncCallStatus @H_772_37@< @H_772_37@GetBookCompletedEventArgs @H_772_37@> @H_772_37@();
        client.GetBookAsync(status);
         // 阻塞线程
@H_772_37@        autoResetEvent.WaitOne();

         if @H_772_37@ (status.CompletedEventArgs.Error @H_772_37@!= @H_772_37@ null @H_772_37@)
        {
             throw @H_772_37@ status.CompletedEventArgs.Error;
        }
        var book @H_772_37@= @H_772_37@ status.CompletedEventArgs.Result;
        viewmode l.ID @H_772_37@= @H_772_37@ book.ID;
        viewmode l.Name @H_772_37@= @H_772_37@ book.Name;
        viewmode l.Author @H_772_37@= @H_772_37@ book.Author;
        viewmode l.Price @H_772_37@= @H_772_37@ book.Price;
    }

     private @H_772_37@ void @H_772_37@ client_GetBookCompleted( object @H_772_37@ sender, GetBookCompletedEventArgs E)
    {
        var status @H_772_37@= @H_772_37@ e.UserState as @H_772_37@ AsyncCallStatus @H_772_37@< @H_772_37@GetBookCompletedEventArgs @H_772_37@> @H_772_37@;

        status.CompletedEventArgs @H_772_37@= @H_772_37@ e;
         // 终止线程阻塞
@H_772_37@        autoResetEvent.Set();
    }
}

四、Silverlight前端调用

　　Siverlight前端就简单布局一个表单作为数据呈现界面，其代码如下：

< Grid x:Name ="LayoutRoot" BACkground ="White" > @H_772_37@
     < Grid HorizontalAlignment ="Left" NAME ="grid1" VerticalAlignment ="Top" Width ="300" Margin ="20" > @H_772_37@
         < Grid.RowDeFinitions > @H_772_37@
             < RowDeFinition Height ="30" ></ RowDeFinition > @H_772_37@
             < RowDeFinition Height ="30" ></ RowDeFinition > @H_772_37@
             < RowDeFinition Height ="30" ></ RowDeFinition > @H_772_37@
             < RowDeFinition Height ="30" ></ RowDeFinition > @H_772_37@
             < RowDeFinition Height ="30" ></ RowDeFinition > @H_772_37@
         </ Grid.RowDeFinitions > @H_772_37@
         < Grid.columnDeFinitions > @H_772_37@
             < columnDeFinition Width ="60" ></ columnDeFinition > @H_772_37@
             < columnDeFinition Width ="*" ></ columnDeFinition > @H_772_37@
         </ Grid.columnDeFinitions > @H_772_37@
         < sdk:Label   HorizontalAlignment ="Left" Content ="图书编号：" VerticalAlignment ="Center" Grid.column ="0" Grid.Row ="0" /> @H_772_37@
         < TextBox Text =" {Binding ID} " Grid.column ="1" Grid.Row ="0" ></ TextBox > @H_772_37@
         < sdk:Label   HorizontalAlignment ="Left" Content ="图书名称：" VerticalAlignment ="Center" Grid.column ="0" Grid.Row ="1" /> @H_772_37@
         < TextBox Text =" {Binding NAME} " Grid.column ="1" Grid.Row ="1" ></ TextBox > @H_772_37@
         < sdk:Label   HorizontalAlignment ="Left" Content ="图书作者：" VerticalAlignment ="Center" Grid.column ="0" Grid.Row ="2" /> @H_772_37@
         < TextBox Text =" {Binding Author} " Grid.column ="1" Grid.Row ="2" ></ TextBox > @H_772_37@
         < sdk:Label   HorizontalAlignment ="Left" Content ="图书价格：" VerticalAlignment ="Center" Grid.column ="0" Grid.Row ="3" /> @H_772_37@
         < TextBox Text =" {Binding PricE} " Grid.column ="1" Grid.Row ="3" ></ TextBox > @H_772_37@

         < Button Content ="查询" Grid.column ="1" Grid.Row ="4" Width ="60" Height ="23" Click ="Button_Click" ></ Button > @H_772_37@
     </ Grid > @H_772_37@
</ Grid >

　　通过按钮执行调用WCF服务接口查询图书信息，按钮事件直接使用上面所写的图书门面类（BookFacade）的调用服务方法即可。

private @H_772_37@ void @H_772_37@ Button_Click( object @H_772_37@ sender, routedEventArgs E)
{
     try @H_772_37@
    {
        ThreadPool.QueueUserWorkItem( delegate @H_772_37@( object @H_772_37@ o)
        {
            Bookviewmodel viewmodel @H_772_37@= @H_772_37@ new @H_772_37@ Bookviewmodel();

             new @H_772_37@ BookFacade().GetBook(viewmodel);

            Deployment.Current.Dispatcher.beginInvoke(() @H_772_37@=> @H_772_37@ this @H_772_37@.DataContext @H_772_37@= @H_772_37@ viewmodel);
        });
    }
     catch @H_772_37@ (Exception eX)
    {
        messageBox.Show(ex.ToString());
    }
}

　　最终的运行如下图所示效果：