B
Brian Henry
I need to mark assemblies with a unique id (GUID in this case) and retrieve
it when the assembly is loaded into my application (a plug-in loader)... the
plug-in assembly all have a class in it which implements our plug-in base
class (which really is a default implementation of a interface IPlugin we
created)
The plug-in class looks like this
Imports bdb
Imports System.Runtime.InteropServices
<Guid("DD3196A0-60E2-4767-B1FE-D41B26B66A90")> _
Public Class SystemAdministration
Inherits bdb.pluginBaseClass
Private f_parentForm As bdb.frmMainWindow
Public Overrides ReadOnly Property name() As String
Get
Return "System Administration"
End Get
End Property
Public Sub New(ByVal parentForm As bdb.frmMainWindow, ByRef application As
Object)
f_parentForm = parentForm
End Sub
Public Overrides Sub StartPlugin()
Dim frmAdmin As New frmAdministration
frmAdmin.MdiParent = f_parentForm
frmAdmin.Show()
End Sub
End Class
=================================
then we have a loader function in our main application that does this, the
problem is at the line "Dim plugGUID As New Guid(CType(o_PluginInstance,
System.Runtime.InteropServices.GuidAttribute).Value)" where the cast is
invalid... how can i get the GUID off the assembly I loaded?! thanks!
====== code here for plug-in loader ==============
' s is a file listing of plug-ins in the directory the loader application
determined were good plug-ins
For Each s In al_goodPlugins
' start to load the plug-in
RaiseEvent PluginLoadStarted("Loading plug-in " & IO.Path.GetFileName(s) &
"...")
Try
' check to see if the dll's comments are saying it's a plugin
' load the file
Dim objAssembly As [Assembly] = [Assembly].LoadFile(s)
Dim classToUser As String = "BDBSDK." & Path.GetFileNameWithoutExtension(s)
' cast the assembly object into the IPlugin interface type
Dim o_PluginInstance As Object = objAssembly.CreateInstance(classToUser,
False, BindingFlags.CreateInstance, Nothing, aArgsList, Nothing, Nothing)
Dim plugGUID As New Guid(CType(o_PluginInstance,
System.Runtime.InteropServices.GuidAttribute).Value)
Dim plugIn As IPlugin = DirectCast(o_PluginInstance, IPlugin)
' if plugin is nothing then we didnt load for some reason
If plugIn Is Nothing Then
' name was plugin and it didn't load? something must of went wrong
MessageBox.Show("The plugin: " & Path.GetFileName(s) & " failed to load
properly", "Plug-in load error", MessageBoxButtons.OK,
MessageBoxIcon.Information)
Else
' if we got here the plugin load worked so far
' get name and an id for plugin plus the plugin object then add to arraylist
Dim pluginInfo As pluginInformation
pluginInfo.plugin = plugIn
pluginInfo.name = plugIn.name
pluginInfo.id = pluginCollection.Count ' since zero based index, the count
will always be the next id number of the array list
pluginCollection.Add(pluginInfo) ' add structure with plugin and info to the
plugin arraylist
End If
Catch ex As Exception
bdb.errorhandler.ErrorCaught(ex) ' we shouldn't get here, but if the plugin
is corrupt it will notify the user of it
End Try
Next
it when the assembly is loaded into my application (a plug-in loader)... the
plug-in assembly all have a class in it which implements our plug-in base
class (which really is a default implementation of a interface IPlugin we
created)
The plug-in class looks like this
Imports bdb
Imports System.Runtime.InteropServices
<Guid("DD3196A0-60E2-4767-B1FE-D41B26B66A90")> _
Public Class SystemAdministration
Inherits bdb.pluginBaseClass
Private f_parentForm As bdb.frmMainWindow
Public Overrides ReadOnly Property name() As String
Get
Return "System Administration"
End Get
End Property
Public Sub New(ByVal parentForm As bdb.frmMainWindow, ByRef application As
Object)
f_parentForm = parentForm
End Sub
Public Overrides Sub StartPlugin()
Dim frmAdmin As New frmAdministration
frmAdmin.MdiParent = f_parentForm
frmAdmin.Show()
End Sub
End Class
=================================
then we have a loader function in our main application that does this, the
problem is at the line "Dim plugGUID As New Guid(CType(o_PluginInstance,
System.Runtime.InteropServices.GuidAttribute).Value)" where the cast is
invalid... how can i get the GUID off the assembly I loaded?! thanks!
====== code here for plug-in loader ==============
' s is a file listing of plug-ins in the directory the loader application
determined were good plug-ins
For Each s In al_goodPlugins
' start to load the plug-in
RaiseEvent PluginLoadStarted("Loading plug-in " & IO.Path.GetFileName(s) &
"...")
Try
' check to see if the dll's comments are saying it's a plugin
' load the file
Dim objAssembly As [Assembly] = [Assembly].LoadFile(s)
Dim classToUser As String = "BDBSDK." & Path.GetFileNameWithoutExtension(s)
' cast the assembly object into the IPlugin interface type
Dim o_PluginInstance As Object = objAssembly.CreateInstance(classToUser,
False, BindingFlags.CreateInstance, Nothing, aArgsList, Nothing, Nothing)
Dim plugGUID As New Guid(CType(o_PluginInstance,
System.Runtime.InteropServices.GuidAttribute).Value)
Dim plugIn As IPlugin = DirectCast(o_PluginInstance, IPlugin)
' if plugin is nothing then we didnt load for some reason
If plugIn Is Nothing Then
' name was plugin and it didn't load? something must of went wrong
MessageBox.Show("The plugin: " & Path.GetFileName(s) & " failed to load
properly", "Plug-in load error", MessageBoxButtons.OK,
MessageBoxIcon.Information)
Else
' if we got here the plugin load worked so far
' get name and an id for plugin plus the plugin object then add to arraylist
Dim pluginInfo As pluginInformation
pluginInfo.plugin = plugIn
pluginInfo.name = plugIn.name
pluginInfo.id = pluginCollection.Count ' since zero based index, the count
will always be the next id number of the array list
pluginCollection.Add(pluginInfo) ' add structure with plugin and info to the
plugin arraylist
End If
Catch ex As Exception
bdb.errorhandler.ErrorCaught(ex) ' we shouldn't get here, but if the plugin
is corrupt it will notify the user of it
End Try
Next