Public Class DynamicClass
    Sub New()

    End Sub

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

Imports System.Reflection
Imports System.Deployment.Application
Imports System.Collections.Generic
Imports Microsoft.Samples.ClickOnceOnDemand
Imports System.Security.Permissions

' 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 DllMappingTable As New Dictionary(Of String, String)()

<SecurityPermission(SecurityAction.Demand, ControlAppDomain:=True)> _
Sub New()
    ' This call is required by the Windows Form Designer.
    InitializeComponent()

    ' Add any initialization after the InitializeComponent() call.
    DllMappingTable("ClickOnceLibrary") = "ClickOnceLibrary"
End Sub

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    AddHandler AppDomain.CurrentDomain.AssemblyResolve, AddressOf Me.CurrentDomain_AssemblyResolve
End Sub

Private Function CurrentDomain_AssemblyResolve(ByVal sender As Object, ByVal args As ResolveEventArgs) As System.Reflection.Assembly
    Dim NewAssembly As Assembly = Nothing

    If (ApplicationDeployment.IsNetworkDeployed) Then
        Dim Deploy As ApplicationDeployment = ApplicationDeployment.CurrentDeployment

        ' Get the DLL name from the argument.
        Dim NameParts As String() = args.Name.Split(",")
        Dim DllName As String = NameParts(0)
        Dim DownloadGroupName As String = DllMappingTable(DllName)

        Try
            Deploy.DownloadFileGroup(DownloadGroupName)
        Catch ex As Exception
            MessageBox.Show("Could not download file group from Web server. Contact administrator. Group name: " & DownloadGroupName & "; DLL name: " & args.Name)
            Throw (ex)
        End Try

        ' 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")
        Catch ex As Exception
            Throw (ex)
        End Try
    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.")
    End If

    Return NewAssembly
End Function

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim DC As New DynamicClass()
    MessageBox.Show("Message is " & DC.Message)
End Sub