Silverlight如何按需加载程序集

最新推荐文章于 2025-09-15 16:08:14 发布

最新推荐文章于 2025-09-15 16:08:14 发布 · 128 阅读

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#操作系统 #ui #c#

本文介绍了一个示例，展示了如何使用WebClient类按需从服务器下载程序集，并使用AssemblyPart类将其加载到当前应用程序域的过程。示例中通过用户界面的一个点击事件触发程序集的异步下载。

下面的示例代码演示如何从主机服务器按需检索程序集，然后将其加载到当前应用程序域中。

此示例使用 WebClient 类启动程序集的异步下载以响应用户鼠标单击。当下载完成后，将使用 AssemblyPart 类来加载此程序集。

此示例假定您已在您的应用程序项目中添加了对程序集的引用。该程序集的"复制本地"值还必须为"False"，这样，它将不会部署在应用程序包中。有关更多信息，请参见应用程序结构。

示例

XAML

复制代码

<usercontrol x:class="SilverlightApplication.HomePage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"><grid background="SandyBrown"><stackpanel x:name="stackPanel"><textblock>Page from Host Application</textblock><textblock mouseleftbuttonup="TextBlock_MouseLeftButtonUp" cursor="Hand">
                Click Here to Display a UI from the Library Assembly
            </textblock></stackpanel></grid></usercontrol>

Visual Basic

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Imports SilverlightLibrary

Partial Public Class HomePage
    Inherits UserControl

    Public Sub New()
        InitializeComponent()
    End Sub

    Private Sub TextBlock_MouseLeftButtonUp(ByVal sender As Object, _
        ByVal e As MouseButtonEventArgs)

        ' Download an "on-demand" assembly. 
        Dim wc As New WebClient()
        AddHandler wc.OpenReadCompleted, AddressOf wc_OpenReadCompleted
        wc.OpenReadAsync(New Uri("SilverlightLibrary.dll", UriKind.Relative))

    End Sub

    Private Sub wc_OpenReadCompleted(ByVal sender As Object, _
        ByVal e As OpenReadCompletedEventArgs)

        If (e.[Error] Is Nothing) AndAlso (e.Cancelled = False) Then

            ' Convert the downloaded stream into an assembly that is 
            ' loaded into current AppDomain. 
            Dim assemblyPart As New AssemblyPart()
            assemblyPart.Load(e.Result)

            DisplayPageFromLibraryAssembly()

        End If

    End Sub

    Private Sub DisplayPageFromLibraryAssembly()

        ' Create an instance of the Page class in the library assembly. 
        Dim page As New Page()

        ' Display the new Page. 
        Me.stackPanel.Children.Add(page)

    End Sub

End Class

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using System; // Uri
using System.Net; // WebClient,OpenReadCompletedEventHandler
using System.Windows; // AssemblyPart
using System.Windows.Controls; // UserControl
using System.Windows.Input; // MouseButtonEventArgs
using SilverlightLibrary; // Page

namespace SilverlightApplication
{
    public partial class HomePage : UserControl
    {
        public HomePage()
        {
            InitializeComponent();
        }

        private void TextBlock_MouseLeftButtonUp(
            object sender, MouseButtonEventArgs e)
        {
            // Download an "on-demand" assembly.
            WebClient wc = new WebClient();
            wc.OpenReadCompleted += 
                new OpenReadCompletedEventHandler(wc_OpenReadCompleted);
            wc.OpenReadAsync(
                new Uri("SilverlightLibrary.dll", UriKind.Relative));
        }

        private void wc_OpenReadCompleted(
            object sender, OpenReadCompletedEventArgs e)
        {
            if ((e.Error == null) && (e.Cancelled == false))
            {
                // Convert the downloaded stream into an assembly that is
                // loaded into current AppDomain.
                AssemblyPart assemblyPart = new AssemblyPart();
                assemblyPart.Load(e.Result);

                DisplayPageFromLibraryAssembly();
            }
        }

        private void DisplayPageFromLibraryAssembly() {

            // Create an instance of the Page class in the library assembly.
            Page page = new Page();

            // Display the new Page. 
            this.stackPanel.Children.Add(page);
        }
    }
}

若要查看该示例的运行版本，请单击下面的链接。

运行此示例

请参见