Q271733: HOWTO: Write a REG_EXPAND_SZ to the Registry
Article: Q271733
Product(s): Microsoft FoxPro
Version(s): 3.0,3.0b,5.0,5.0a,6.0
Operating System(s):
Keyword(s): kbAPI kbvfp300 kbvfp300b kbvfp500 kbvfp500a kbvfp600 kbGrpDSFox kbDSupport kbCodeSnippe
Last Modified: 11-JUN-2002
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The information in this article applies to:
- Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a, 6.0
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SUMMARY
=======
This article describes how to write a REG_EXPAND_SZ registry value. According to
the Microsoft Developer's Network (MSDN), the REG_EXPAND_SZ registry value
is...
"... a null-terminated string that contains unexpanded references to
environment variables (for example, "%PATH%"). It will be a Unicode or ANSI
string depending on whether you use the Unicode or ANSI functions."
MORE INFORMATION
================
IMPORTANT: This article contains information about modifying the registry.
Before you modify the registry, make sure to back it up and make sure that you
understand how to restore the registry if a problem occurs. For information
about how to back up, restore, and edit the registry, click the following
article number to view the article in the Microsoft Knowledge Base:
Q256986 Description of the Microsoft Windows Registry
WARNING: If you use Registry Editor incorrectly, you may cause serious problems
that may require you to reinstall your operating system. Microsoft cannot
guarantee that you can solve problems that result from using Registry Editor
incorrectly. Use Registry Editor at your own risk.
The information about the registry editor in this article is for Microsoft
Windows NT-based computers and Microsoft Windows 2000-based computers. If you
are running a Microsoft Windows 95-based, Microsoft Windows 98-based, or
Microsoft Millennium-based computer, you need to use the Regedit.exe file
instead of the Regedt32.exe file.
NOTE: This article uses a registry key that is created just for testing purposes.
This registry key should be deleted when you complete testing.
1. Start the Registry Editor (Regedt32.exe).
2. Locate the following key in the registry:
HKEY_LOCAL_MACHINE\Software
3. On the Edit menu, click Add Key, and then add the following registry Key:
VfpREGTest
4. Expand the HKEY_LOCAL_MACHINE\Software value. Locate and then select the
VfpREGTest key that you added in step 3.
5. On the Edit menu, click Add Value, and then add the following registry value:
Value Name: TestREG_EXPAND_SZ
Data Type: REG_EXPAND_SZ
Value: %Temp%
6. Quit the Registry Editor.
7. In Microsoft Visual FoxPro, create a program and enter the following code:
*Start of Code
#DEFINE HKEY_CLASSES_ROOT -2147483648
#DEFINE HKEY_CURRENT_USER -2147483647
#DEFINE HKEY_LOCAL_MACHINE -2147483646
#DEFINE HKEY_USERS -2147483645
LOCAL nKey, cSubKey, cValue, lSuccess, cExpandPart, cNonExpandPart
nKey = HKEY_LOCAL_MACHINE
cSubKey = "Software\VfpRegTest"
cValue = "TestREG_EXPAND_SZ"
cExpandPart = "WINDIR"
cNonExpandPart = "\System"
lSuccess = WriteREG_EXPAND_SZ(nKey, cSubKey, cValue, cExpandPart, cNonExpandPart)
IF (lSuccess) THEN
=MESSAGEBOX("Value was Written to the Registry.")
ELSE
=MESSAGEBOX("Value was not Written to the Registry.")
ENDIF
FUNCTION WriteREG_EXPAND_SZ
* This function writes a REG_EXPAND_SZ value to the registry. It will return
* True if successful and False if not.
PARAMETERS nKey, cSubKey, cValue, cExpandPart, cNonExpandPart
* nKey The root key to open. It can be any of the constants defined below
* #DEFINE HKEY_CLASSES_ROOT -2147483648
* #DEFINE HKEY_CURRENT_USER -2147483647
* #DEFINE HKEY_LOCAL_MACHINE -2147483646
* #DEFINE HKEY_USERS -2147483645
* cSubKey The SubKey to open.
* cValue The value that is going to be written.
* cExpandPart The expanded part of the string written the registry.
* cNonExpandPart The part of the string that isn't expanded.
* Constants that are needed for Registry functions
#DEFINE REG_EXPAND_SZ 2
* WIN 32 API functions that are used
DECLARE Integer RegOpenKey IN Win32API ;
Integer nHKey, String @cSubKey, Integer @nResult
DECLARE Integer RegSetValueEx IN Win32API ;
Integer hKey, String lpszValueName, Integer lpdwReserved,;
Integer lpdValueType, String lpbValue, Integer lpcbValueSize
DECLARE Integer RegCloseKey IN Win32API Integer nHKey
* Local variables used
LOCAL nErrCode && Error Code returned from Registry functions
LOCAL nKeyHandle && Handle to Key that is opened in the Registry
LOCAL lpdwValueType && Type of Value that we are writing
LOCAL lpbValue && The data stored in the value
LOCAL lpcbValueSize && Size of the variable
LOCAL lpdwReserved && Reserved Must be 0
* Initialize the variables
nKeyHandle = 0
lpdwReserved = 0
lpdwValueType = REG_EXPAND_SZ
nErrCode = RegOpenKey(nKey, cSubKey, @nKeyHandle)
* If the error code isn't 0, then the key doesn't exist or can't be opened.
IF (nErrCode # 0) THEN
RETURN .F.
ENDIF
lpbValue = "%" + ALLTRIM(cExpandPart) + "%" + ALLTRIM(cNonExpandPart)
lpcbValueSize = LEN(lpbValue)
nErrCode=RegSetValueEx(nKeyHandle, cValue, lpdwReserved, @lpdwValueType, @lpbValue, @lpcbValueSize)
=RegCloseKey(nKeyHandle)
* Check to see if we were successful
IF (nErrCode # 0) THEN
RETURN .F.
ENDIF
RETURN .T.
* End of Code
8. Run the code that you created in step 7. A message box appears that displays
the status of the function. If the function is successful, the message box
text states:
Value was Written to the Registry.
If the function is unsuccessful, the text states:
Value was not Written to the Registry.
9. You can replace the nKey, cSubKey, cExpandPart, and cNonExpandPart with your
information.
REFERENCES
==========
For additional information about obtaining values from the registry, click the
article number below to view the article in the Microsoft Knowledge Base:
Q244675 HOWTO:Use Windows Script Host to Read, Write, Delete Registry
(c) Microsoft Corporation 2000, All Rights Reserved. Contributions by Mark
Barnard, Microsoft Corporation.
Additional query words: Regedt32 Regedit
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Keywords : kbAPI kbvfp300 kbvfp300b kbvfp500 kbvfp500a kbvfp600 kbGrpDSFox kbDSupport kbCodeSnippet
Technology : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b kbVFP500 kbVFP600 kbVFP500a
Version : :3.0,3.0b,5.0,5.0a,6.0
Issue type : kbhowto
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