Silverlight中同步调用WebClient的解决办法，是同步！

如何建立web服务并引用的细节，不是本文的介绍的目标，不再赘述。在silverlight调用服务器端服务的时候，默认情况下是进行异步调用的，代码如下：

        private void button2_Click(object sender, RoutedEventArgs e)
        {
            Service1Client sc = new Service1Client();
            sc.DoWorkCompleted += new EventHandler<DoWorkCompletedEventArgs>(sc_DoWorkCompleted);
            sc.DoWorkAsync(textBox1.Text);

        }

        void sc_DoWorkCompleted(object sender, DoWorkCompletedEventArgs e)
        {
            textBox2.Text = e.Result;
        }

若是你的调用非常复杂的话，比如当这个调用完成的时候开始下一个调用，然后又进行下一个调用，各个调用之间存在关联关系的话，一直XX_DoWorkCompleted会让你头大，并且不利于代码的管理。若碰到过这样的问题的朋友一定很希望如果能够同步调用就好了，这篇文章将帮到你。或者现在不需要，等你需要的时候记得用就行了，别像我当初那样难为的不行。

主要是需要引用一个类库的问题，这个类库是外国人写的，名称为DanielVaughan.dll,下载完之后，首先需要在项目中添加对它的引用，如下图，

然后在程序中添加对两个空间的引用，如下图：



将原来的添加botton1事件：

        private void button1_Click(object sender, RoutedEventArgs e)
        {

            string dd = textBox1.Text;
            string res = "NULL";
            ThreadPool.QueueUserWorkItem(delegate
            {
                Service1 sv = ChannelManager.Instance.GetChannel<Service1>();
                /* Perform synchronous WCF call. */
                res = SynchronousChannelBroker.PerformAction<string, string>(sv.BeginDoWork, sv.EndDoWork, dd);
                Dispatcher.BeginInvoke(delegate
                {
                    textBox2.Text +="\r\n同步调用--"+ res+"\r\n";
                });
            });
        }

这样就可以实现对WebClient的同步调用了，当你需要关联调用WebClient3次以上的时候 可以考虑使用这个类库，如果只是简单的调用下的话，没有必要使用。
页面全部代码：

<UserControl x:Class="SilverlightApplication2.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="300" d:DesignWidth="400" xmlns:dataInput="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data.Input" Width="640" Height="480">

    <Grid x:Name="LayoutRoot">
        <Grid.Background>
            <LinearGradientBrush EndPoint="0.443,0.621" StartPoint="0.443,-2.509">
                <GradientStop Color="#FF5C6768"/>
                <GradientStop Color="White" Offset="1"/>
            </LinearGradientBrush>
        </Grid.Background>
        <Button Content="同步调用服务" Height="40" HorizontalAlignment="Left" Margin="67,98,0,0" Name="button1" VerticalAlignment="Top" Width="120" Click="button1_Click" />
        <dataInput:Label Height="50" HorizontalAlignment="Left" Margin="67,188,0,0" Name="label2" VerticalAlignment="Top" Width="46" Content="状态：" FontSize="16" />
        <TextBox Height="40" HorizontalAlignment="Left" Margin="165,27,0,0" Name="textBox1" VerticalAlignment="Top" Width="300" FontSize="16" />
        <TextBox Height="100" HorizontalAlignment="Left" Margin="146,188,0,0" Name="textBox2" VerticalAlignment="Top" Width="400" FontSize="16" TextWrapping="Wrap" Text="尚未调用服务" />
        <Button Content="异步调用服务" Height="40" HorizontalAlignment="Left" Margin="346,98,0,0" Name="button2" VerticalAlignment="Top" Width="120" Click="button2_Click" />
        <dataInput:Label Height="40" HorizontalAlignment="Left" Margin="67,27,0,0" Name="label1" VerticalAlignment="Top" Width="92" FontSize="16" Content="输入文本：" />
    </Grid>
</UserControl>

处理程序全部代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using SilverlightApplication2.ServiceReference1;
using System.Threading;
using DanielVaughan;

namespace SilverlightApplication2
{
    public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();
            UISynchronizationContext.Instance.Initialize(Dispatcher);
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {

            string dd = textBox1.Text;
            string res = "NULL";
            ThreadPool.QueueUserWorkItem(delegate
            {
                Service1 sv = ChannelManager.Instance.GetChannel<Service1>();
                /* Perform synchronous WCF call. */
                res = SynchronousChannelBroker.PerformAction<string, string>(sv.BeginDoWork, sv.EndDoWork, dd);
                Dispatcher.BeginInvoke(delegate
                {
                    textBox2.Text +="\r\n同步调用--"+ res+"\r\n";
                });
            });
        }

        private void button2_Click(object sender, RoutedEventArgs e)
        {
            Service1Client sc = new Service1Client();
            sc.DoWorkCompleted += new EventHandler<DoWorkCompletedEventArgs>(sc_DoWorkCompleted);
            sc.DoWorkAsync(textBox1.Text);
        }


        void sc_DoWorkCompleted(object sender, DoWorkCompletedEventArgs e)
        {
            textBox2.Text += "异步调用--" + e.Result + "\r\n";
        }
    }
}

Service代码：

using System;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Activation;

namespace SilverlightApplication2.Web
{
    [ServiceContract(Namespace = "")]
    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
    public class Service1
    {
        [OperationContract]
        public string  DoWork(string aa)
        {
            // 在此处添加操作实现
            return "调用服务完成，返回你输入的值:"+aa;
        }

        // 在此处添加更多操作并使用 [OperationContract] 标记它们
    }
}

程序运行截图：

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欢迎广大园友共同探讨，觉得好的话请推荐下。本人技术水平有限，如有不足之处，还请园友多多批评指正，谢谢。