逐步解說：依 ClickOnce 部署 API 的要求下載組件

發行項
02/22/2013

根據預設，在 ClickOnce 應用程式中包含的所有組件，都會在應用程式首次執行時下載。不過，您的應用程式可能有些部分是由一小群使用者使用。在此情況下，只有在建立一種類型的組件時，才需要下載組件。下列逐步解說會示範如何將應用程式中的某些組件標記為「選擇項」，以及如何在 Common Language Runtime (CLR) 要求這些組件時，使用 System.Deployment.Application 命名空間中的類別來下載這些組件。

注意事項
您的應用程式需要在完全信任的狀態下執行，才能使用這個程序。

必要條件

您將需要下列其中一個元件才能完成這個逐步解說：

Windows SDK。 Windows SDK 可從 Microsoft 下載中心下載。
Visual Studio。

建立專案

建立使用視需要下載組件的專案

建立名為 ClickOnceOnDemand 的目錄。
開啟 Windows SDK 命令提示字元，或是 Visual Studio 命令提示字元。
切換到 ClickOnceOnDemand 目錄。
使用下列命令產生公開/私密金鑰組：
```
sn -k TestKey.snk
```

使用 [記事本] 或其他文字編輯器，定義名為 DynamicClass，並具有名為 Message 單一屬性的類別。

Public Class DynamicClass
    Sub New()

    End Sub

    Public ReadOnly Property Message() As String
        Get
            Message = "Hello, world!"
        End Get
    End Property
End Class

using System;
using System.Collections.Generic;
using System.Text;

namespace Microsoft.Samples.ClickOnceOnDemand
{
    public class DynamicClass
    {
        public DynamicClass() {}

        public string Message
        {
            get
            {
                return ("Hello, world!");
            }
        }
    }
}

根據您使用的語言，以名為 ClickOnceLibrary.cs 或 ClickOnceLibrary.vb 的檔案將文字儲存到 ClickOnceOnDemand 目錄。

將此檔案編譯為組件。

csc /target:library /keyfile:TestKey.snk ClickOnceLibrary.cs

vbc /target:library /keyfile:TestKey.snk ClickOnceLibrary.vb

若要取得組件的公開金鑰語彙基元，請使用下列命令：
```
sn -T ClickOnceLibrary.dll
```

使用文字編輯器建立新的檔案，並輸入下列程式碼。這個程式碼會建立 Windows Form 應用程式，該應用程式會在需要時下載 ClickOnceLibrary 組件。

Imports System
Imports System.Windows.Forms
Imports System.Deployment.Application
Imports System.Drawing
Imports System.Reflection
Imports System.Collections.Generic
Imports Microsoft.Samples.ClickOnceOnDemand


Namespace Microsoft.Samples.ClickOnceOnDemand
   <System.Security.Permissions.SecurityPermission(System.Security.Permissions.SecurityAction.Demand, Unrestricted:=true)> _
   Class Form1
      Inherits Form

        ' Maintain a dictionary mapping DLL names to download file groups. This is trivial for this sample,
        ' but will be important in real-world applications where a feature is spread across multiple DLLs,
        ' and you want to download all DLLs for that feature in one shot. 
        Dim DllMapping as Dictionary(Of String, String) = new Dictionary(of String, String)()

      Public Sub New()
         ' Add button to form.
            Dim GetAssemblyButton As New Button()
            GetAssemblyButton.Location = New Point(100, 100)
            GetAssemblyButton.Text = "Get assembly on demand"
            AddHandler GetAssemblyButton.Click, AddressOf GetAssemblyButton_Click

            Me.Controls.Add(GetAssemblyButton)

            DllMapping("ClickOnceLibrary") = "ClickOnceLibrary"
            AddHandler AppDomain.CurrentDomain.AssemblyResolve, AddressOf CurrentDomain_AssemblyResolve
      End Sub

        <STAThread()> _
        Shared Sub Main()
            Application.EnableVisualStyles()
            Application.Run(New Form1())
        End Sub

        Private Function CurrentDomain_AssemblyResolve(ByVal sender As Object, ByVal args As ResolveEventArgs) As Assembly
            If ApplicationDeployment.IsNetworkDeployed Then
                Dim deploy As ApplicationDeployment = ApplicationDeployment.CurrentDeployment

                ' Get the DLL name from the Name argument.
                Dim nameParts() as String = args.Name.Split(",")
                Dim dllName as String = nameParts(0)
        Dim downloadGroupName as String = DllMapping(dllName)

                Try
                    deploy.DownloadFileGroup(downloadGroupName)
                Catch de As DeploymentException

                End Try

                ' Load the assembly.
                Dim newAssembly As Assembly = Nothing

                Try
                    newAssembly = Assembly.LoadFile(Application.StartupPath & "\\" & dllName & ".dll," & _  
            "Version=1.0.0.0, Culture=en, PublicKeyToken=03689116d3a4ae33")
                Catch ex As Exception
                    MessageBox.Show("Could not download assembly on demand.")
                End Try

                CurrentDomain_AssemblyResolve = newAssembly
            Else
                CurrentDomain_AssemblyResolve = Nothing
            End If
        End Function

        Private Sub GetAssemblyButton_Click(ByVal sender As Object, ByVal e As EventArgs)
            Dim ourClass As New DynamicClass()
            MessageBox.Show("DynamicClass string is: " + ourClass.Message)
        End Sub
    End Class
End Namespace

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Reflection;
using System.Deployment.Application;
using Microsoft.Samples.ClickOnceOnDemand;

namespace ClickOnceOnDemand
{
    [System.Security.Permissions.SecurityPermission(System.Security.Permissions.SecurityAction.Demand, Unrestricted=true)]
    public class Form1 : Form
    {
        // Maintain a dictionary mapping DLL names to download file groups. This is trivial for this sample,
        // but will be important in real-world applications where a feature is spread across multiple DLLs,
        // and you want to download all DLLs for that feature in one shot. 
        Dictionary<String, String> DllMapping = new Dictionary<String, String>();

        public static void Main()
        {
            Form1 NewForm = new Form1();
            Application.Run(NewForm);
        }

        public Form1()
        {
            // Configure form. 
            this.Size = new Size(500, 200);
            Button getAssemblyButton = new Button();
            getAssemblyButton.Size = new Size(130, getAssemblyButton.Size.Height);
            getAssemblyButton.Text = "Test Assembly";
            getAssemblyButton.Location = new Point(50, 50);
            this.Controls.Add(getAssemblyButton);
            getAssemblyButton.Click += new EventHandler(getAssemblyButton_Click);

            DllMapping["ClickOnceLibrary"] = "ClickOnceLibrary";
            AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(CurrentDomain_AssemblyResolve);
        }

        /*
         * Use ClickOnce APIs to download the assembly on demand.
         */
        private Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
        {
            Assembly newAssembly = null;

            if (ApplicationDeployment.IsNetworkDeployed)
            {
                ApplicationDeployment deploy = ApplicationDeployment.CurrentDeployment;

                // Get the DLL name from the Name argument.
                string[] nameParts = args.Name.Split(',');
                string dllName = nameParts[0];
                string downloadGroupName = DllMapping[dllName];

                try
                {
                    deploy.DownloadFileGroup(downloadGroupName);
                }
                catch (DeploymentException de)
                {
                    MessageBox.Show("Downloading file group failed. Group name: " + downloadGroupName + "; DLL name: " + args.Name);
                    throw (de);
                }

                // Load the assembly.
                // Assembly.Load() doesn't work here, as the previous failure to load the assembly
                // is cached by the CLR. LoadFrom() is not recommended. Use LoadFile() instead.
                try
                {
                    newAssembly = Assembly.LoadFile(Application.StartupPath + @"\" + dllName + ".dll," +  
            "Version=1.0.0.0, Culture=en, PublicKeyToken=03689116d3a4ae33");
                }
                catch (Exception e)
                {
                    throw (e);
                }
            }
            else
            {
                //Major error - not running under ClickOnce, but missing assembly. Don't know how to recover.
                throw (new Exception("Cannot load assemblies dynamically - application is not deployed using ClickOnce."));
            }


            return (newAssembly);
        }

        private void getAssemblyButton_Click(object sender, EventArgs e)
        {
            DynamicClass dc = new DynamicClass();
            MessageBox.Show("Message: " + dc.Message);
        }
    }
}

在程式碼中，尋找 LoadFile 的呼叫。
將 PublicKeyToken 設為您之前擷取的值。
將檔案儲存為 Form1.cs 或 Form1.vb。

使用下列命令將它編譯為可執行檔。

csc /target:exe /reference:ClickOnceLibrary.dll Form1.cs

vbc /target:exe /reference:ClickOnceLibrary.dll Form1.vb

將組件標記為選擇項

使用 MageUI.exe 將 ClickOnce 應用程式中的組件標記為選擇項

使用 MageUI.exe，建立應用程式資訊清單，如逐步解說：手動部署 ClickOnce 應用程式中所述。請使用下列應用程式資訊清單的設定：
- 將應用程式資訊清單命名為 ClickOnceOnDemand。
- 在 [檔案] 頁面上的 [ClickOnceLibrary.dll] 資料列，將 [檔案類型] 欄設為 [無]。
- 在 [檔案] 頁面上 [ClickOnceLibrary.dll] 資料列的 [群組] 欄中，輸入 ClickOnceLibrary.dll。
使用 MageUI.exe，建立部署資訊清單，如逐步解說：手動部署 ClickOnce 應用程式中所述。請使用下列部署資訊清單的設定：
- 將部署資訊清單命名為 ClickOnceOnDemand。

測試新組件

若要測試視需要下載的組件

將您的 ClickOnce 部署上載至 Web 伺服器。
輸入部署資訊清單的 URL，以便從 Web 瀏覽器啟動以 ClickOnce 部署的應用程式。如果您呼叫 ClickOnce 應用程式 ClickOnceOnDemand，並將它上載至 adatum.com 的根目錄，您的 URL 會如下所示：
```
http://www.adatum.com/ClickOnceOnDemand/ClickOnceOnDemand.application
```
當您的主表單出現時，按下 Button。您應該會看到在訊息方塊視窗中顯示 "Hello, World!" 的字串。

請參閱

參考

ApplicationDeployment

共用方式為