如何获取VBCodeProvider返回对象

Question

I have a program that allows users to setup a client/server to control/run commands from a remote location. Now i'm trying to implement server plugins, and I'm doing that by loading every .vb file in a folder contained inside the current running directory. Everything is great, and the code from the external files compiles just fine... Only problem is, Its returning nothing when I try to compile the script and use one of the methods inside it.

Here's some code for you to check out. My error is in the 2nd. Any idea on how to fix this?

The Interaction Interface:

Public Interface LinkingInterface
    Property name As String
    Property statetag As String
    Sub selected(ByVal Sock As Integer)
    Sub deselected(ByVal Sock As Integer)
    Sub load()
    Function generateOutput(ByVal input As String, ByVal Sock As Integer) As String
End Interface

Detection/Loading of the "Modes" (add-ins):

For Each file In My.Computer.FileSystem.GetFiles("modes\")
            Dim thisMode As LinkingInterface = LoadMode(My.Computer.FileSystem.ReadAllText(file))
            thisMode.load() '<---------------------------My error is here, saying its a null ref.
            modes_InterfaceCollection.Add(thisMode)     'Public modes_InterfaceCollection As New Microsoft.VisualBasic.Collection()
            modes_nameIndex.Add(thisMode.name)          'Public modes_nameIndex As New Specialized.StringCollection()
        Next

'LoadMode' Function

Public Function LoadMode(ByVal code As String) As LinkingInterface
        Using provider As New VBCodeProvider()
            Dim parameters As New CompilerParameters()
            parameters.GenerateInMemory = True
            parameters.ReferencedAssemblies.Add(Reflection.Assembly.GetExecutingAssembly().Location)
            parameters.MainClass = "Remote_Command_Line.MainModule"
            Dim interfaceNamespace As String = GetType(LinkingInterface).Namespace
            Dim codeBuilder As New Text.StringBuilder
            Dim namespaces() As String = New String() {"Microsoft.VisualBasic", "System", "System.Console", "System.Collections", "System.Collections.Generic", _
                                                       "System.Data", "System.Diagnostics", "Remote_Command_Line.MainModule"}
            Dim codeString As New StringBuilder
            For Each namespacestring As String In namespaces
                codeString.AppendLine("Imports " & namespacestring)
            Next
            codeString.AppendLine(code)
            Dim results As CompilerResults = provider.CompileAssemblyFromSource(parameters, codeString.ToString)

            'I commented out this just for debugging purposes
            'If results.Errors.HasErrors Then
            'For Each scriptError As CompilerError In results.Errors
            'WriteLine(scriptError.ToString)
            'Next
            'Else
            Return CType(results.CompiledAssembly.CreateInstance(results.CompiledAssembly.GetType.Name), LinkingInterface)
            'End If
        End Using
    End Function

The Testing file 'test.vb':

Public Class test_mode
    'Designed for RCL mode 1.0b
    'Matthew 2013
    'used for managing the local filesystem.  



    '####################################
#Region "Properties"
    'all of these properties listed are required --------------------
    Implements LinkingInterface
    Property name As String Implements LinkingInterface.name         'the name the client refers to you in the 'modeswitch' command
    Property statetag As String Implements LinkingInterface.statetag 'short tag displayed on the client when active before the input signal '>'
    '----------------------------------------------------------------
    Public curDirDatabank As New Specialized.StringCollection()

#End Region
    '####################################





    '####################################
#Region "Subs"

    'Its required to have, but not required to do anything. This load sub is here for any modes that may require an initialization
    Private Sub load() Implements LinkingInterface.load 'REQUIRED
        name = "file" : statetag = "file"
        MsgBox("Testing: It's loaded")
    End Sub

    Private Sub selected(ByVal Sock As Integer) Implements LinkingInterface.selected
        MsgBox("Testing: '" & Sock & "' selected the File mode")
    End Sub

    Private Sub deselected(ByVal Sock As Integer) Implements LinkingInterface.deselected
        MsgBox("Testing: '" & Sock & "' deselected the File mode")
    End Sub

    Private Function generateOutput(ByVal input As String, ByVal Sock As Integer) As String Implements LinkingInterface.generateOutput 'REQUIRED
        Return ("Testing: '" & Sock & "' said '" & input & "'")
    End Function

#End Region
    '####################################

End Class

Answer 1

the following line is wrong.

Return CType(results.CompiledAssembly.CreateInstance(results.CompiledAssembly.GetType.Name), LinkingInterface)

You need to search through the loaded classes for one implementing your interface (it being VB you automatically get classes generated for the My namespace objects such as My.Computer)

Try this instead

        For Each t As Type In results.CompiledAssembly.GetTypes()
            If t.GetInterface(GetType(LinkingInterface).Name) IsNot Nothing Then
                Return CType(results.CompiledAssembly.CreateInstance(t.Name), LinkingInterface)
            End If
        Next

        Return Nothing