Registry Keys

Installation

Need to add a registry key
HKCU\Software\Microsoft\Office\12.0\Excel\Options\ OPEN1 - /R "MyXLL.dll"
If the add-in is not in the default add-ins folder then the full path must be provided
The Excel-DNA runtime contains a small loader (the .XLL) that loads the .NET runtime, then checks the configuration (.dna) file and accordingly loads the managed assembly.
The managed assemblies are then inspected using the .NET Reflection API and the appropriate methods are registered.

Upgrading from 32 bit to 64 bit

Const ISIT_32_OR_64_PATH = "HKLM\Software\Microsoft\Office\16.0\Outlook\" 
Const EXCEL_ADDIN_PATH = "HKCU\Software\Microsoft\Office\16.0\Excel\Options\" 

Const ADDIN_REG_VALUE_32 = "/R ""C:\Program Files (x86)\Better Solutions\ExcelDNALibrary-AddIn.xll """ 
Const ADDIN_REG_VALUE_64 = "/R ""C:\Program Files (x86)\Better Solutions\ExcelDNALibrary-AddIn64.xll """ 

Function RegistrationKeyExists(key) 
    On Error Resume Next 
    objShell.RegRead (key) 
    If Err = 0 Then 
        RegistrationKeyExists = True 
    Else 
        RegistrationKeyExists = False 
    End If 
End Function 

Function RegistrationKeyValueGet(name) 
    On Error Resume Next 
    Dim value 
    value = objShell.RegRead(name) 
    If Err = 0 Then 
        RegistrationKeyValueGet = value 
    Else 
        RegistrationKeyValueGet = "" 
    End If 
End Function 

Function RegistrationKeyValueSet(name, value) 
    On Error Resume Next 
    objShell.RegWrite name, value, "REG_SZ" 
    If Err = 0 Then 
        RegistrationKeyValueSet = True 
    Else 
        RegistrationKeyValueSet = False 
    End If 
End Function 

Function RegistrationKeyValueDelete(name) 
    On Error Resume Next 
    objShell.RegDelete name 
    If Err = 0 Then 
        RegistrationKeyValueDelete = True 
    Else 
        RegistrationKeyValueDelete = False 
    End If 
End Function 

Dim objShell 
Dim ADDIN_REG_VALUE 
Dim BIT3264 
Dim count 
Dim value 
Dim exists 
Dim exists_32bit 
Dim success 

Set objShell = CreateObject("WScript.Shell") 
WScript.Echo "Excel-DNA Upgrade Script" 

WScript.Echo "Checking if Office is 32bit or 64bit 
If RegistrationKeyExists(ISIT_32_OR_64_PATH) Then 
    BIT3264 = RegistrationKeyValueGet(ISIT_32_OR_64_PATH & "Bitness") 
    WScript.Echo "32or64  - " & BIT3264 

    If BIT3264 = "x64" Then 
       WScript.Echo "64 bit Office" 
    End If 

    If BIT3264 = "x32" Then 
       WScript.Echo "32 bit Office" 
    End If 
End If 

.// Check OPEN 
If RegistrationKeyExists(EXCEL_ADDIN_PATH) Then 
    value = RegistrationKeyValueGet(EXCEL_ADDIN_PATH & "OPEN") 
    If Len(value) > 0 Then 
        WScript.Echo "OPEN exists, its value is - " & value 

        If (value = ADDIN_REG_VALUE_32) Then 
            WScript.Echo "OPEN - 32 bit formula add-in found" 
            If BIT3264 = "x64" Then 
                WScript.Echo "OPEN - Changing it to 64 bit formula add-in" 
                success = RegistrationKeyValueSet(EXCEL_ADDIN_PATH & "OPEN" & count, ADDIN_REG_VALUE_64) 
                64bitexists = true 
            End If 
        End If 

        If (value = ADDIN_REG_VALUE_64) Then 
            WScript.Echo "OPEN - 64 bit formula add-in found" 
            If BIT3264 = "x32" Then 
                WScript.Echo "OPEN - Changing it to 32 bit formula add-in" 
                success = RegistrationKeyValueSet(EXCEL_ADDIN_PATH & "OPEN" & count, ADDIN_REG_VALUE_32) 
                32bitexists = true 
            End If 
        End If 
    End If 

.// Check OPEN1 ... OPEN20 
    For count = 1 To 20 
        value = RegistrationKeyValueGet(EXCEL_ADDIN_PATH & "OPEN" & count) 
        WScript.Echo "OPEN" & count & " = " & value 
        If (value = ADDIN_REG_VALUE_32) Then 
            WScript.Echo "OPEN" & count & " - 32 bit formula add-in found" 
            If BIT3264 = "x64" Then 
                If (64bitexists = False) Then 
                    WScript.Echo "OPEN" & count & " - Changing it to 64 bit add-in" 
                    success = RegistrationKeyValueSet(EXCEL_ADDIN_PATH & "OPEN" & count, ADDIN_REG_VALUE_64) 
                    64bitexists = true 
                Else 
                    WScript.Echo "OPEN" & count & " - 64 bit registration already exists, so remove" 
                    success = RegistrationKeyValueDelete(excelAddinPath & "OPEN" & count) 
                End If 
            End If 
            If BIT3264 = "x32" Then 
                If (32bitexists = False) Then 
                    WScript.Echo "OPEN" & count & " - Changing it to 32 bit add-in" 
                    success = RegistrationKeyValueSet(EXCEL_ADDIN_PATH & "OPEN" & count, ADDIN_REG_VALUE_32) 
                    32bitexists = true 
                Else 
                    WScript.Echo "OPEN" & count & " - 32 bit registration already exists, so remove" 
                    success = RegistrationKeyValueDelete(excelAddinPath & "OPEN" & count) 
                End If 
            End If 
        End If 

        If (value = ADDIN_REG_VALUE_64) Then 
            WScript.Echo "OPEN" & count & " - 64 bit formula add-in found" 
            If BIT3264 = "x64" Then 
                If (64bitexists = False) Then 
                    WScript.Echo "OPEN" & count & " - Changing it to 64 bit add-in" 
                    success = RegistrationKeyValueSet(EXCEL_ADDIN_PATH & "OPEN" & count, ADDIN_REG_VALUE_64) 
                    64bitexists = true 
                Else 
                    WScript.Echo "OPEN" & count & " - 64 bit registration already exists, so remove" 
                    success = RegistrationKeyValueDelete(excelAddinPath & "OPEN" & count) 
                End If 
            End If 
            If BIT3264 = "x32" Then 
                If (32bitexists = False) Then 
                    WScript.Echo "OPEN" & count & " - Changing it to 32 bit add-in" 
                    success = RegistrationKeyValueSet(EXCEL_ADDIN_PATH & "OPEN" & count, ADDIN_REG_VALUE_32) 
                    32bitexists = true 
                Else 
                    WScript.Echo "OPEN" & count & " - 32 bit registration already exists, so remove" 
                    success = RegistrationKeyValueDelete(excelAddinPath & "OPEN" & count) 
                End If 
            End If 
        End If 
    Next icount 
End If 
Set objShell = Nothing