How to Determine the Path for an Office Application

This article includes sample code that illustrates how you can programmatically determine the installation path for a Microsoft Office application given the ProgID for that application.

Automation servers have a unique ProgID that you typically use to automate that server. The following list provides the ProgIDs for Office applications:


Note that the table above provides version-independent ProgIDs. Applications have version-dependent ProgIDs as well that you can use with the sample code provided in this article. For instance, Microsoft Excel has a version-independent ProgID "Excel.Application" and version-dependent ProgIDs such as "Excel.Application.8" and "Excel.Application.9."

Given a ProgID for an out-of-process server, you can obtain its location by examining the registry. An out-of-process server has a key in the registry at:

HKEY_LOCAL_MACHINE\Software\Classes\PROGID\CLSID

that provides its unique CLSID (or Class ID). That CLSID then has a registry key at:

HKEY_LOCAL_MACHINE\Software\Classes\CLSID\{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxx}\LocalServer32

where the path to the server is specified. To illustrate, if you want to determine the path for Microsoft Excel using the ProgID "Excel.Application," you would examine this key in the registry:

HKEY_LOCAL_MACHINE\Software\Classes\Excel.Application\CLSID

and, depending on what version of Excel is installed, you would find that the CLSID for Excel.Application is "{00020841-0000-0000-C000-000000000046}." Next, using this CLSID, you would examine the following registry key to find the path for EXCEL.EXE:

HKEY_LOCAL_MACHINE\Software\Classes\CLSID\{00020841-0000-0000-C000-000000000046}\LocalServer32

All of this can be done programmatically using the registry API functions in advapi32.dll.

Sample Code

1. Start a new Standard EXE project in Visual Basic. Form1 is created by default.
2. Add a TextBox and a CommandButton to Form1.
3. Add the following code to the module for Form1:

   Private Declare Function RegOpenKeyEx Lib "advapi32.dll" Alias _
      "RegOpenKeyExA" (ByVal hKey As Long, ByVal lpSubKey As String, _
      ByVal ulOptions As Long, ByVal samDesired As Long, phkResult As Long) _
      As Long
   
   Private Declare Function RegQueryValueEx Lib "advapi32.dll" Alias _
      "RegQueryValueExA" (ByVal hKey As Long, ByVal lpValueName As String, _
      ByVal lpReserved As Long, lpType As Long, _
      ByVal lpData As String, lpcbData As Long) As Long  
                  'Note that if you declare the lpData parameter as String, 
                  'you must pass it ByVal.                      
                                                                                      
   Private Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long
   
   Const REG_SZ As Long = 1
   Const KEY_ALL_ACCESS = &H3F
   Const HKEY_LOCAL_MACHINE = &H80000002
      
   Private Sub Command1_Click()
   Dim hKey As Long
   Dim RetVal As Long
   Dim sProgId As String
   Dim sCLSID As String
   Dim sPath As String
   
      sProgId = Text1.Text
   
      'First, get the clsid from the progid
      'from the registry key:
      'HKEY_LOCAL_MACHINE\Software\Classes\<PROGID>\CLSID
      RetVal = RegOpenKeyEx(HKEY_LOCAL_MACHINE, "Software\Classes\" & _
         sProgId & "\CLSID", 0&, KEY_ALL_ACCESS, hKey)
      If RetVal = 0 Then
         Dim n As Long
         RetVal = RegQueryValueEx(hKey, "", 0&, REG_SZ, "", n)
         sCLSID = Space(n)
         RetVal = RegQueryValueEx(hKey, "", 0&, REG_SZ, sCLSID, n)
         sCLSID = Left(sCLSID, n - 1)  'drop null-terminator
         RegCloseKey hKey
      End If
      
      'Now that we have the CLSID, locate the server path at
      'HKEY_LOCAL_MACHINE\Software\Classes\CLSID\ 
      '     {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxx}\LocalServer32
   
       RetVal = RegOpenKeyEx(HKEY_LOCAL_MACHINE, _
           "Software\Classes\CLSID\" & sCLSID & "\LocalServer32", 0&, _
         KEY_ALL_ACCESS, hKey)
      If RetVal = 0 Then
         RetVal = RegQueryValueEx(hKey, "", 0&, REG_SZ, "", n)
         sPath = Space(n)
   
         RetVal = RegQueryValueEx(hKey, "", 0&, REG_SZ, sPath, n)
         sPath = Left(sPath, n - 1)
         MsgBox sPath
         RegCloseKey hKey
      End If
         
   End Sub
   					

4. Press the F5 key to run the program.
5. In the TextBox, type Excel.Application and click the CommandButton. The path to Excel.exe appears in a MessageBox.

For additional information, please click the article numbers below to view the articles in the Microsoft Knowledge Base: