Easily Overwrite VB Plugin without closing Messenger

Ok guys we all have found in the past that this is near impossible to do right? Well up until now it was.

The steps to do this are in this order
1. Unregister DLL
2. Reload Plus! Plugins

The first step in the process is call a DllUnregisterServer (or using regsvr32

) to unregister the DLL.

In a Module

code:

'Declare API Variables Used to Unregister the DLL

Option Explicit

Public Declare Function FreeLibrary Lib "kernel32" (ByVal hLibModule As Long) As Long
Public Declare Function LoadLibrary Lib "kernel32" Alias "LoadLibraryA" (ByVal lpLibFileName As String) As Long
Private Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, _
ByVal hWnd As Long, _
ByVal Msg As Any, _
ByVal wParam As Any, _
ByVal lParam As Any) _
As Long

Public Declare Function WaitForSingleObject Lib "kernel32" (ByVal hHandle As Long, _
ByVal dwMilliseconds As Long) _
As Long

Public Declare Function DeleteFile Lib "kernel32" Alias "DeleteFileA" (ByVal lpFileName As String) As Long

Public Const INFINITE = &HFFFF

'Function to call the DllUnregisterServer
'Usage: UnregisterServer Me.hWnd, "C:\Program Files\MessengerPlus! 3\Plugins\MyDLL.dll"
'DllServerPath - Must be a COMPLETE PATH

Public Function UnregisterServer(hWnd As Long, DllServerPath As String)
On Error Resume Next

Dim lb As Long, pa As Long

'Check to see if the file exists, if it doesn't then exit after displaying a message box

'Load the DLL into memory

lb = LoadLibrary(DllServerPath)

If lb Then

MsgBox "File Not Found!" & vbCrLf & "Unable to continue. " & _
"(DllServerPath must be the full path to the file, " & _
"or this program must be in the same directory.)"
Exit Function

End If

'Get the address of the function DllUnregisterServer from the DLL

pa = GetProcAddress(lb, "DllUnregisterServer")

'Send the DLLs function to the main form

If CallWindowProc(pa, hWnd, ByVal 0&, ByVal 0&, ByVal 0&) = ERROR_SUCCESS Then
MsgBox "Successful"
Else
MsgBox "Unuccessful"
End If
FreeLibrary lb
End Function

'Delete the Plugin, code will not continue until this is done (WaitForSingleObject)
Public Function DeletePlugin() As Boolean
Dim nMsg As Long, retVal As Long

retVal = DeleteFile("C:\Program Files\MessengerPlus! 3\Plugins\MyDLL.dll")
WaitForSingleObject retVal, INFINITE
DeletePlugin = CBool(retVal)

End Function

The second step is to Reload the Plugins. Now Plus! wont be able to load our DLL because it has been unregistered from the system

code:

Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, _
ByVal wMsg As Long, _
ByVal wParam As Long, _
lParam As Any) _
As Long

Public Declare Function RegisterWindowMessageA Lib "user32" (ByVal lpString As String) As Long

Public Declare Function WaitForSingleObject Lib "kernel32" (ByVal hHandle As Long, _
ByVal dwMilliseconds As Long) _
As Long

Public Const INFINITE = &HFFFF
Public Const HWND_BROADCAST = &HFFFF&

'Unload the Plugins, code will not continue until this is done (WaitForSingleObject)
Public Function UnloadPlugins()
Dim nMsg As Long, retVal As Long

nMsg = RegisterWindowMessageA("MessengerPlus_PluginChange")
retVal = SendMessage(HWND_BROADCAST, nMsg, 0&, 0&)
WaitForSingleObject retVal, INFINITE
End Function

On the other hand if you want to trim this down you can use the following

code:

Public Function DllUnregister(strFile As String)

Dim retVal As Long

retval = shell("regsvr32 /u " & Chr(34) & strFile & Chr(34)), vbHide
WaitForSingleObject retval, INFINITE

End Function

Now with that said instead of hardcoding the path into the program you will want to get the value from the registry as follows.

In a Module

code:
Public Const REG_SZ = 1
Public Const REG_BINARY = 3
Public Const HKEY_CURRENT_USER = &H80000001
Public Const HKEY_LOCAL_MACHINE = &H80000002
Public Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long
Public Declare Function RegCreateKey Lib "advapi32.dll" Alias "RegCreateKeyA" (ByVal hKey As Long, _
ByVal lpSubKey As String, _
phkResult As Long) _
As Long

Public Declare Function RegDeleteValue Lib "advapi32.dll" Alias "RegDeleteValueA" (ByVal hKey As Long, _
ByVal lpValueName As String) _
As Long

Public Declare Function RegOpenKey Lib "advapi32.dll" Alias "RegOpenKeyA" (ByVal hKey As Long, _
ByVal lpSubKey As String, _
phkResult As Long) _
As Long

Public Declare Function RegQueryValueExA Lib "advapi32.dll" (ByVal hKey As Long, _
ByVal lpValueName As String, _
ByVal lpReserved As Long, _
lpType As Long, _
lpData As Any, _
lpcbData As Long) _
As Long

Public Declare Function RegQueryValueExA Lib "advapi32.dll" (ByVal hKey As Long, _
ByVal lpValueName As String, _
ByVal lpReserved As Long, _
lpType As Long, _
lpData As Any, _
lpcbData As Long) _
As Long

Public Function RegQueryStringValue(ByVal hKey As Long, ByVal strValueName As String) As String
Dim lResult As Long, lValueType As Long, strBuf As String, lDataBufSize As Long
lResult = RegQueryValueExA(hKey, strValueName, 0, lValueType, ByVal 0, lDataBufSize)
If lResult = 0 Then
If lValueType = REG_SZ Then
strBuf = String(lDataBufSize, Chr$(0))
lResult = RegQueryValueExA(hKey, strValueName, 0, 0, ByVal strBuf, lDataBufSize)
If lResult = 0 Then
RegQueryStringValue = Left$(strBuf, InStr(1, strBuf, Chr$(0)) - 1)
End If
ElseIf lValueType = REG_BINARY Then
Dim strData As Integer
lResult = RegQueryValueExA(hKey, strValueName, 0, 0, strData, lDataBufSize)
If lResult = 0 Then
RegQueryStringValue = strData
End If
End If
End If
End Function

Public Function GetStringvalue(hKey As Long, strPath As String, strValue As String) As String
Dim Ret
RegOpenKey hKey, strPath, Ret
GetStringvalue = RegQueryStringValue(Ret, strValue)
RegCloseKey Ret
End Function

On A Form

code:
Private Sub Form_Load()

Dim sText As String

sText = LCase(GetStringvalue(HKEY_LOCAL_MACHINE, "software\patchou\msgplus2\", "plugindir"))
If sText = vbNullString Then
sText = LCase(GetStringvalue(HKEY_CURRENT_USER, "software\patchou\msgplus2\", "plugindir"))
If sText = vbNullString Then
MsgBox "Messenger Plus! not installed"
Else
MsgBox "Plugin Dir: " & sText
End If
Else
MsgBox "Plugin Dir: " & sText
End If

End Sub

The path that is returned from GetStringValue() will be the path directly for the plugins so you can continue on from there. If anyone needs help with anything don't hesitate to ask.

Matty

(Cook if any of this code is wrong or can be done differently then

on you, its 1:20 in the morning and I am tired but wanted to post this so).

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