How To Read a REG_SZ Value From the Registry

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Article ID: 258556 - View products that this article applies to.
This article was previously published under Q258556
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SUMMARY

This article shows how to read a REG_SZ value from the registry.

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:
256986 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.

This information about the registry editor in this article is for Microsoft Windows NT and Microsoft Windows 2000. If you are running Windows 9X, you have to use Regedit.exe instead of Regedt32.exe.

NOTE: This article uses a registry key that is created just for testing and should be deleted when you are finished.
  1. Start 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:
       Key Name:   VfpRegTest
    					
  4. Click on the Key added in step 3. On the Edit menu, click Add Value, and then add the following value:
       Value Name: TestREG_SZ
       Data Type:  REG_SZ
       Value:      This is a Test. 
    					
  5. Quit Registry Editor.
  6. From Visual FoxPro, create a program and enter the following code:
    *Start of Code
    #DEFINE HKEY_LOCAL_MACHINE          -2147483646
    
    LOCAL nKey, cSubKey, cValue,  cValueRead
    nKey = HKEY_LOCAL_MACHINE
    cSubKey = "Software\VfpRegTest"
    cValue = "TestREG_SZ"
    
    cValueRead = ReadREG_SZ(nKey, cSubKey, cValue)
    IF (EMPTY(cValueRead)) THEN
       =MESSAGEBOX("Function Not Successful.")
    ELSE
       ? cValueRead
       =MESSAGEBOX("Function Successful.")
    ENDIF
    
    FUNCTION ReadREG_SZ
    * This function reads a REG_SZ value from the registry. If successful,
    * it will return the value read. If not successful, it will return an empty string.
       PARAMETERS  nKey, cSubKey, cValue
       * 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 read.
    
       * Constants that are needed for Registry functions
       #DEFINE REG_SZ   1
    
       * WIN 32 API functions that are used
       DECLARE Integer RegOpenKey IN Win32API ;
          Integer nHKey, String @cSubKey, Integer @nResult
       DECLARE Integer RegQueryValueEx IN Win32API ;
          Integer nHKey, String lpszValueName, Integer dwReserved,;
          Integer @lpdwType, String @lpbData, Integer @lpcbData
       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 looking for
       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_SZ
       lpbValue = ""
       
       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 ""
       ENDIF
    
       lpcbValueSize = 1 
       * Get the size of the data in the value
       nErrCode=RegQueryValueEx(nKeyHandle, cValue, lpdwReserved, @lpdwValueType, @lpbValue, @lpcbValueSize)
    
       * Make the buffer big enough
       lpbValue = SPACE(lpcbValueSize)   
       nErrCode=RegQueryValueEx(nKeyHandle, cValue, lpdwReserved, @lpdwValueType, @lpbValue, @lpcbValueSize)
       
       =RegCloseKey(nKeyHandle)
       IF (nErrCode # 0) THEN
          RETURN ""
       ENDIF
    
       lpbValue = LEFT(lpbValue, lpcbValueSize - 1)
    RETURN lpbValue
    * End of Code 
  7. Run the program created in step 6. A message box appears reading "Function Successful" and the value appears on the screen.
  8. You can replace nKey, cSubKey, and cValue with your information to be read from the registry.
(c) Microsoft Corporation 2000, All Rights Reserved. Contributions by Mark Barnard, Microsoft Corporation.

REFERENCES


For additional information obtaining values from the registry, click the article number below to view the article in the Microsoft Knowledge Base:
244675 How To Use Windows Script Host to Read, Write, Delete Registry

Properties

Article ID: 258556 - Last Review: July 1, 2004 - Revision: 2.2
APPLIES TO
  • Microsoft Visual FoxPro 3.0 Standard Edition
  • Microsoft Visual FoxPro 3.0b Standard Edition
  • Microsoft Visual FoxPro 5.0 Standard Edition
  • Microsoft Visual FoxPro 5.0a
  • Microsoft Visual FoxPro 6.0 Professional Edition
Keywords: 
kbapi kbcodesnippet kbhowto KB258556

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