Silverlight读取Web.config配置文件

touchinsert

浏览: 1288245 次
性别:
来自: 北京

最近访客更多访客>>

yin_bp

u012363178

wangyy

dongguangming88

博主相关

博客

微博

相册

留言

关于我

文章分类

全部博客 (1629)

社区版块

存档分类

2012-01 ( 61)
2011-12 ( 68)
2011-11 ( 26)
更多存档...

Silverlight Application是客户端程序，没有也无法访问服务端的web.config，它自己也不允许添加.config文件，加上Silverilght 3.0之后，原来ASP.NET 2.0中的Silveright控件也被去掉了，要读取web.config就又更困难了一些。

不过如果仔细分析一下的话，可以发现Silverlight App是由一个Web Application来host的，而那个Web Application是可以方便地配置的，于是，可以考虑由网站来把配置传给Silverlight，宿主Silverlight的Page文件中会有这样一段代码：

可以看到这里有很多关于Silverlight的参数，我们可以从这段代码下手，在这里为其添加一个新的参数：

可以看到其中有一个param标签的name为InitParams，其值可以在App.xaml.cs中的Application_Startup事件处理方法中，使用传入StartupEventArgs参数的InitParams属性取得，类型为IDictionary<string, string>。下面来看一下具体的方法：

1. 首先，我们需要在Page文件中加入一个Literal控件，以便能够动态地将<param name="InitParams" value="" />赋到Page中，但是在Visual Studio 2010里，默认为我们创建的ASPX页面没有.cs文件，需要我们创建一个新的ASPX页面，把原先<HTML></HTML>当中的内容Copy过来，并加上Literal控件，如下方代码所示：

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="HostPage.aspx.cs" Inherits="GetWebConfig.Web.HostPage" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>GetWebConfig</title>
    <style type="text/css">
    html, body {
	    height: 100%;
	    overflow: auto;
    }
    body {
	    padding: 0;
	    margin: 0;
    }
    #silverlightControlHost {
	    height: 100%;
	    text-align:center;
    }
    </style>
    <script type="text/javascript" src="Silverlight.js"></script>
    <script type="text/javascript">
        function onSilverlightError(sender, args) {
            var appSource = "";
            if (sender != null && sender != 0) {
                appSource = sender.getHost().Source;
            }

var errorType = args.ErrorType;
            var iErrorCode = args.ErrorCode;

if (errorType == "ImageError" || errorType == "MediaError") {
                return;
            }

var errMsg = "Unhandled Error in Silverlight Application " + appSource + "\n";

errMsg += "Code: " + iErrorCode + "    \n";
            errMsg += "Category: " + errorType + "       \n";
            errMsg += "Message: " + args.ErrorMessage + "     \n";

if (errorType == "ParserError") {
                errMsg += "File: " + args.xamlFile + "     \n";
                errMsg += "Line: " + args.lineNumber + "     \n";
                errMsg += "Position: " + args.charPosition + "     \n";
            }
            else if (errorType == "RuntimeError") {
                if (args.lineNumber != 0) {
                    errMsg += "Line: " + args.lineNumber + "     \n";
                    errMsg += "Position: " + args.charPosition + "     \n";
                }
                errMsg += "MethodName: " + args.methodName + "     \n";
            }

throw new Error(errMsg);
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div id="silverlightControlHost">
        <object data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%">
		  <param name="source" value="ClientBin/GetWebConfig.xap"/>
		  <param name="onError" value="onSilverlightError" />
		  <param name="background" value="white" />
		  <param name="minRuntimeVersion" value="4.0.50826.0" />
		  <param name="autoUpgrade" value="true" />
                  <asp:Literal ID="litInitParams" runat="server" />
		  <a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=4.0.50826.0" style="text-decoration:none">
 			  <img src="http://go.microsoft.com/fwlink/?LinkId=161376" alt="Get Microsoft Silverlight" style="border-style:none"/>
		  </a>
	    </object><iframe id="_sl_historyFrame" style="visibility:hidden;height:0px;width:0px;border:0px"></iframe></div>
    </form>
</body>
</html>

2. 接下来，我们要在这个页面的后台.cs文件中读取web.config的内容，并且把它赋给Literal控件：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Collections.Specialized;
using System.Web.Configuration;
using System.Text;
 
namespace SL_ReadConfigFile.Web
{
    public partial class SL_ReadConfigFile : System.Web.UI.Page
    {
        private string _seperator = ",";
 
        protected void Page_Load( object sender , EventArgs e )
        {
            Response.Cache.SetCacheability( HttpCacheability.NoCache );
            WriteInitParams();
        }
 
        private void WriteInitParams()
        {
            NameValueCollection appSettings = WebConfigurationManager.AppSettings;
            StringBuilder stringBuilder = new StringBuilder();
            stringBuilder.Append( "<param name=\"InitParams\" value=\"" );
            string paramContent = string.Empty;
            for( int i = 0 ; i < appSettings.Count ; i++ )
            {
                if( paramContent.Length > 0 )
                {
                    paramContent += _seperator;
                }
                paramContent += string.Format( "{0}={1}" , appSettings.GetKey( i ) , appSettings[ i ] );
             }
             stringBuilder.Append(paramContent );
             stringBuilder.Append( "\" />" );
             this.litInitParams.Text = stringBuilder.ToString();
         }
     }
 }

3. 在App.xaml.cs中的Application_Startup事件处理方法中，使用传入StartupEventArgs参数的InitParams属性取得，类型为IDictionary<string, string>：

using System;
using System.Collections.Generic;
using System.Windows;
 
namespace SL_ReadConfigFile
{
    public partial class App : Application
    {
        private IDictionary<string , string> _configurations;
        public IDictionary<string , string> Configurations
        {
            get
            {
                return _configurations;
            }
        }
 
        public App()
        {
            this.Startup += this.Application_Startup;
            this.Exit += this.Application_Exit;
            this.UnhandledException += this.Application_UnhandledException;
            InitializeComponent();
        }
 
        private void Application_Startup( object sender , StartupEventArgs e )
        {
            _configurations = e.InitParams;
            this.RootVisual = new MainPage();
        }
 
        private void Application_Exit( object sender , EventArgs e )
        {
 
        }
 
        private void Application_UnhandledException( object sender , ApplicationUnhandledExceptionEventArgs e )
        {
            if( !System.Diagnostics.Debugger.IsAttached )
            {
                e.Handled = true;
                Deployment.Current.Dispatcher.BeginInvoke( delegate { ReportErrorToDOM( e ); } );
            }
        }
  
        private void ReportErrorToDOM( ApplicationUnhandledExceptionEventArgs e )
        {
            try
            {
                string errorMsg = e.ExceptionObject.Message + e.ExceptionObject.StackTrace;
                errorMsg = errorMsg.Replace( '"' , '\'' ).Replace( "\r\n" , @"\n" );
                System.Windows.Browser.HtmlPage.Window.Eval( "throw new Error(\"Unhandled Error in Silverlight Application " + errorMsg + "\");" );
            }
            catch( Exception )
            {
            }
        }
    }
}

4. 最后就是在Silverlight页面当中获取InitParams的值并显示到页面上：

<UserControl xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"  x:Class="SL_ReadConfigFile.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:DesignWidth="800" d:DesignHeight="600"
    Width="Auto" Height="Auto" xmlns:toolkit="http://schemas.microsoft.com/winfx/2006/xaml/presentation/toolkit">
 
    <Grid x:Name="LayoutRoot" Background="Transparent">
        <Grid.RowDefinitions>
            <RowDefinition Height="50"></RowDefinition>
            <RowDefinition></RowDefinition>
            <RowDefinition Height="30"></RowDefinition>
        </Grid.RowDefinitions>
        <TextBlock HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="24">Silverlight Reads web.config Demo</TextBlock>
        <sdk:DataGrid Grid.Row="1" Name="dgdConfigurations">
        </sdk:DataGrid>
        <StackPanel Orientation="Horizontal" Grid.Row="2" HorizontalAlignment="Center">
            <Button Name="btnShowEntry" Width="200" Margin="10,0" Click="btnShowEntry_Click">
                <StackPanel Orientation="Horizontal">
                    <TextBlock VerticalAlignment="Center">Read number</TextBlock>
                    <toolkit:NumericUpDown Name="numericUpDown" Margin="5,0" DecimalPlaces="0"/>
                    <TextBlock VerticalAlignment="Center">entry</TextBlock></StackPanel>
            </Button>
            <Button Name="btnBindConfig" Width="200" Margin="10,0" Click="btnBindConfig_Click">Binding Configurations</Button>
        </StackPanel>
    </Grid>
</UserControl>

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;
 
namespace SL_ReadConfigFile
{
    public partial class MainPage : UserControl
    {
        private IDictionary<string , string> _configurations;
        public MainPage()
        {
            InitializeComponent();
 
            _configurations =  ( Application.Current as App ).Configurations;
 
            if( _configurations.Count > 0 )
            {
                numericUpDown.Minimum = 1;
                numericUpDown.Maximum = _configurations.Count;
            }
 
        }
 
        private void btnBindConfig_Click( object sender , RoutedEventArgs e )
        {
            this.dgdConfigurations.ItemsSource = _configurations;
        }
 
        private void btnShowEntry_Click( object sender , RoutedEventArgs e )
        {
            string entryContent = string.Format( "{0} = {1}" , _configurations.ElementAt( ( int ) numericUpDown.Value - 1 ).Key , _configurations.ElementAt( ( int ) numericUpDown.Value - 1 ).Value );
            MessageBox.Show( entryContent );
        }
    }
}

5. 我们已经可以读取到web.config里面的值了，但是，要注意的是，在ASPX页面当中InitParams会以明文显示在Source Code当中，如果是数据库连接串或是其他需要加密的信息，请自己开发加密算法来解决这一问题，下一篇我会介绍如何加密InitParams中的值。

分享到：