The registry and combobox

[abdul]

I have combobox which will add the item (whatever) you type in itself. Now I want to save all the items in the combobox in registry so that I can retrieve them later.

How do I do that and how do I add them back to the combobox when my program starts?

Thanks

[Sastraxi]

There are several API functions that can help - look them up at MSDN.

[Vlatko]

RegSetValue
The RegSetValue function sets the data for the default or unnamed value of a specified registry key. The data must be a text string.

This function is provided for compatibility with Windows version 3.1. Win32-based applications should use the RegSetValueEx function, which allows you to set any number of named values of any data type.

LONG RegSetValue(
HKEY hKey, // handle to key to set value for
LPCTSTR lpSubKey, // address of subkey name
DWORD dwType, // type of value
LPCTSTR lpData, // address of value data
DWORD cbData // size of value data
);

Parameters
hKey
Handle to a currently open key or any of the following predefined reserved handle values:
HKEY_CLASSES_ROOT
HKEY_CURRENT_CONFIG
HKEY_CURRENT_USER
HKEY_LOCAL_MACHINE
HKEY_USERS
Windows NT: HKEY_PERFORMANCE_DATA
Windows 95 and Windows 98: HKEY_DYN_DATA

lpSubKey
Pointer to a null-terminated string containing the name of a subkey of the hKey parameter. The function sets the default value of the specified subkey. If this parameter is NULL or points to an empty string, the function sets the default value of the key identified by hKey.
dwType
Specifies the type of information to be stored. This parameter must be the REG_SZ type. To store other data types, use the RegSetValueEx function.
lpData
Pointer to a null-terminated string containing the data to set for the default value of the specified key.
cbData
Specifies the length, in bytes, of the string pointed to by the lpData parameter, not including the terminating null character.
Return Values
If the function succeeds, the return value is ERROR_SUCCESS.

If the function fails, the return value is a nonzero error code defined in WINERROR.H. You can use the FormatMessage function with the FORMAT_MESSAGE_FROM_SYSTEM flag to get a generic description of the error.

Remarks
If the key specified by the lpSubKey parameter does not exist, the RegSetValue function creates it.

Value lengths are limited by available memory. Long values (more than 2048 bytes) should be stored as files with the filenames stored in the registry. This helps the registry perform efficiently.

The key identified by the hKey parameter must have been opened with KEY_SET_VALUE access. To open the key, use the RegCreateKeyEx or RegOpenKeyEx function. If the ANSI version of this function is used (either by explicitly calling RegSetValueA or by not defining UNICODE before including the WINDOWS.H file), the lpData parameter must be an ANSI character string. The string is converted to Unicode before it is stored in the registry.

RegOpenKey
The RegOpenKey function opens the specified key. This function is provided for compatibility with Windows version 3.1. Win32-based applications should use the RegOpenKeyEx function.

LONG RegOpenKey(
HKEY hKey, // handle to open key
LPCTSTR lpSubKey, // address of name of subkey to open
PHKEY phkResult // address of handle to open key
);

Parameters
hKey
Handle to a currently open key or any of the following predefined reserved handle values:
HKEY_CLASSES_ROOT
HKEY_CURRENT_CONFIG
HKEY_CURRENT_USER
HKEY_LOCAL_MACHINE
HKEY_USERS
Windows NT: HKEY_PERFORMANCE_DATA
Windows 95 and Windows 98: HKEY_DYN_DATA

The key opened by the RegOpenKey function is a subkey of the key identified by hKey.

lpSubKey
Pointer to a null-terminated string containing the name of the key to open. This key must be a subkey of the key identified by the hKey parameter. If this parameter is NULL or a pointer to an empty string, the function returns the same handle that was passed in.
phkResult
Pointer to a variable that receives a handle to the opened key. When you no longer need the returned handle, call the RegCloseKey function to close it.
Return Values
If the function succeeds, the return value is ERROR_SUCCESS.

If the function fails, the return value is a nonzero error code defined in WINERROR.H. You can use the FormatMessage function with the FORMAT_MESSAGE_FROM_SYSTEM flag to get a generic description of the error.

Remarks
The RegOpenKey function uses the default security access mask to open a key. If opening the key requires a different mask, the function fails, returning ERROR_ACCESS_DENIED. An application should use the RegOpenKeyEx function to specify an access mask in this situation.

Unlike the RegCreateKey function, RegOpenKey does not create the specified key if the key does not exist in the database.

RegQueryValue
The RegQueryValue function retrieves the data associated with the default or unnamed value of a specified registry key. The data must be a null-terminated string.

This function is provided for compatibility with Windows version 3.1. Win32-based applications should use the RegQueryValueEx function.

LONG RegQueryValue(
HKEY hKey, // handle to key to query
LPCTSTR lpSubKey,
// name of subkey to query
LPTSTR lpValue, // buffer for returned string
PLONG lpcbValue // receives size of returned string
);

Parameters
hKey
Handle to a currently open key or any of the following predefined reserved handle values:
HKEY_CLASSES_ROOT
HKEY_CURRENT_CONFIG
HKEY_CURRENT_USER
HKEY_LOCAL_MACHINE
HKEY_USERS
Windows NT: HKEY_PERFORMANCE_DATA
Windows 95 and Windows 98: HKEY_DYN_DATA

lpSubKey
Pointer to a null-terminated string containing the name of the subkey of the hKey parameter for which the default value is retrieved. If this parameter is NULL or points to an empty string, the function retrieves the default value for the key identified by hKey.
lpValue
Pointer to a buffer that receives the null-terminated string associated with the default value of the specified key.
If lpValue is NULL, and lpcbValue is non-NULL, the function returns ERROR_SUCCESS, and stores the size of the data, in bytes, in the variable pointed to by lpcbValue. This lets an application determine the best way to allocate a buffer for the value's data.

lpcbValue
Pointer to a variable that specifies the size, in bytes, of the buffer pointed to by the lpValue parameter. When the function returns, this variable contains the size of the data copied to lpValue, including the terminating null character.
If the buffer specified by lpValue parameter is not large enough to hold the data, the function returns the value ERROR_MORE_DATA, and stores the required buffer size, in bytes, into the variable pointed to by lpcbValue.

In all cases the value returned in lpcbValue includes the size of the terminating null character in the string.

Return Values
If the function succeeds, the return value is ERROR_SUCCESS.

If the function fails, the return value is a nonzero error code defined in WINERROR.H. You can use the FormatMessage function with the FORMAT_MESSAGE_FROM_SYSTEM flag to get a generic description of the error.

Remarks
The key identified by the hKey parameter must have been opened with KEY_QUERY_VALUE access (KEY_READ access includes KEY_QUERY_VALUE access).

If the ANSI version of this function is used (either by explicitly calling RegQueryValueA or by not defining UNICODE before including the WINDOWS.H file), this function converts the stored Unicode string to an ANSI string before copying it to the buffer specified by the lpValue parameter.

If you don't know how to use them i will send you some example later.

[abdul]

Yes please send me some examples but I can add/edit/delete a single key like "Version#".
The combobox has lots of items in it so I don't if I make that many keys or I make one key that saperates the items by a specific symbol like "$$"
Can you give me an example of that please?