Grab Registry Settings through VBA using WMI

Using Windows Management Instrumentation (WMI) we can read, write and create registry keys anywhere in the registry.

The following is a series of procedures you can use to do so. These procedures are based on code found at Microsoft Access VBA Uses WMI to Read the Registry. This page will only cover methods for reading, writing and creating string values. See the above link for methods to do the same with binary and DWORD values.

First, the obligatory disclaimer: Write to your registry with caution. Overwriting existing keys can render your Windows installation unusable.

We'll start the code by defining a custom enumeration; the list of possible hives from which you can read.

Public Enum Hive
  HKEY_CLASSES_ROOT
  HKEY_CURRENT_USER
  HKEY_LOCAL_MACHINE
  HKEY_USERS
  HKEY_CURRENT_CONFIG
End Enum

And we'll need a way for our functions to determine which hive was chosen (based on the custom enum):

Function GetHive(hivetype As Hive) As Variant
' return enumerated value depending on the hive chosen
  Select Case hivetype
    Case 0
      GetHive = &H80000000  ' HKEY_CLASSES_ROOT
    Case 1
      GetHive = &H80000001  ' HKEY_CURRENT_USER
    Case 2
      GetHive = &H80000002  ' HKEY_LOCAL_MACHINE
    Case 3
      GetHive = &H80000003  ' HKEY_USERS
    Case 4
      GetHive = &H80000005  ' HKEY_CURRENT_CONFIG
  End Select

End Function

Check Any String Value from the Registry

The function GetStringValFromRegistry takes our custom hive type, the registry key to retrieve, and the name of the entry whose value we want to retrieve. It also includes another function, GetStdRegProv, which calls the WMI service and returns the appropriate object.

Function GetStringValFromRegistry(hivetype As Hive, registryKey As String, _
    keyValue As String) As String

Dim objReg As Object
Dim strKeyPath As String
Dim ValueName As String
Dim strValue As String

  Set objReg = GetStdRegProv

  strKeyPath = registryKey
  ValueName = keyValue

  ' put key value into strValue variable
  objReg.GetStringValue GetHive(hivetype), strKeyPath, ValueName, strValue
  GetStringValFromRegistry = strValue

End Function

Function GetStdRegProv() As Object
' http://msdn.microsoft.com/en-us/library/aa394600(VS.85).aspx
Dim strComputer As String

  strComputer = "."

  Set GetStdRegProv = GetObject("winmgmts:" _
                              & "{impersonationLevel=impersonate}!\\" _
                              & strComputer & "\root\default:StdRegProv")
End Function

Sample usage

Let's call the function by checking the installation path for Office 2003. The registry key is located at

HKEY_LOCAL_MACHINE\Software\Microsoft\Office\11.0\Common\InstallRoot

and the key name is

Path

Sub TestRegistryReadAndWrite()

Dim registryKey As String
Dim keyName As String

  registryKey = "Software\Microsoft\Office\11.0\Common\InstallRoot"
  keyName = "Path"

  ' get string value from registry
  Debug.Print GetStringValFromRegistry(HKEY_LOCAL_MACHINE, registryKey, keyName)

End Sub

Create Registry Keys

We can create registry keys anywhere in the registry we want. This is different from SaveSetting which only uses HKEY_CURRENT_USER\Software\VB and VBA Program Settings.

The CreateKey function takes the hive location where we want the new key, and the full key name and path where it should be placed.

Function CreateKey(hivetype As Hive, registryKey As String)

Dim objReg As Object
Dim strKeyPath As String

  Set objReg = GetStdRegProv

  strKeyPath = registryKey

  ' create the key
  objReg.CreateKey GetHive(hivetype), strKeyPath

End Function

Notice how the GetHive function is used to return the constant value needed by WMI to determine which hive to use.

Sample usage

The following sample procedure will create the key "NewKey" in HKEY_LOCAL_MACHINE\Software.

Sub TestRegistryReadAndWrite()

Dim registryKey As String

  registryKey = "Software\NewKey"

  ' create new key
  CreateKey HKEY_LOCAL_MACHINE, registryKey

End Sub

Create Registry (String) Values

Finally, we can create new registry values anywhere in the registry. This is as simple as calling the SetStringValue function and passing in the appropriate values.

Function CreateKeyValue(hivetype As Hive, registryKey As String, _
    keyName As String, keyValue As String)

Dim objReg As Object
Dim strKeyPath As String
Dim strValueName As String
Dim strValue As String

  Set objReg = GetStdRegProv

  strKeyPath = registryKey
  strValueName = keyName
  strValue = keyValue

  ' create the key value
  objReg.SetStringValue GetHive(hivetype), strKeyPath, strValueName, strValue

End Function

Sample usage:

Sub TestRegistryReadAndWrite()

Dim registryKey As String
Dim keyValue As String
Dim keyName As String

  registryKey = "Software\NewKey"
  keyName = "NewName"
  keyValue = "This is a value"

  ' add name/value to new key
  CreateKeyValue HKEY_LOCAL_MACHINE, registryKey, keyName, keyValue

End Sub

Putting it all together

Let's see how we can read, create and write to the registry all in one procedure. Here are all of the sample procedures rolled into one. After checking the install path for Office 2003, we'll create a new registry key, populate it with a name/value, and then retrieve the new value to verify that it was added.

Sub TestRegistryReadAndWrite()

Dim registryKey As String
Dim keyValue As String
Dim keyName As String

  registryKey = "Software\Microsoft\Office\11.0\Common\InstallRoot"
  keyName = "Path"

  ' get string value from registry
  Debug.Print GetStringValFromRegistry(HKEY_LOCAL_MACHINE, registryKey, keyName)

  registryKey = "Software\NewKey"

  ' create new key
  CreateKey HKEY_LOCAL_MACHINE, registryKey

  keyName = "NewName"
  keyValue = "This is a value"

  ' add name/value to new key
  CreateKeyValue HKEY_LOCAL_MACHINE, registryKey, keyName, keyValue
  ' check our newly added value
  Debug.Print GetStringValFromRegistry(HKEY_LOCAL_MACHINE, registryKey, keyName)

End Sub