* VB-CODE (2)
Tip 146: Retrieving the Printer Name from the Windows 95 Registry

August 31, 1995

Abstract
Microsoft® Windows® 95 uses the registry to determine which 
applications and
hardware items are installed in the computer system. This article 
explains how
you can retrieve the name of the default printer from the registry from 
within
a Visual Basic® application.

Manipulating the Windows 95 Registry in Visual Basic
The Microsoft® Windows® 95 registry is a database of information that 
contains
configuration details about the hardware and software installed in your 
computer
system. Under Windows version 3.1, this information was maintained 
through
initialization (.INI) files.

The registry is composed of keys. Each key may contain a specific value 
or other
subkeys, which in turn may contain values or other subkeys. You can 
examine or
modify the contents of the registration database by using the Microsoft 
Win32®
registry application programming interface (API) functions in a Visual 
Basic
program or by using the Registry Editor (REGEDIT).

The example program below shows how to use the Win32 registry API 
functions to
retrieve the default printer's name from the registry.

The first step is to call the RegOpenKeyEx function.This function opens 
the
specified key in the registration database. In this case, you want to 
open the
subkey that is associated with the printer. This subkey is stored in 
the registry
as:
SYSTEM\Current Control Set\Control\Print\Printers\Default

You also need to tell the RegOpenKeyEx function that you want to work 
with the
Default subkey. After the program calls this function, a value that is 
set to
zero is returned if the function was successful.

The next step is to retrieve the actual value stored for the key that 
you are
interrogating. Because you want to retrieve the name that is assigned 
to the
default printer, you should call the RegQueryValueEx function. You must 
tell
this function that you want to retrieve the value that was given to the 
Default
subkey.

Finally, you must call the RegCloseKey function to release the handle 
of the key
that you have been accessing in the registration database. This 
terminates access
to the registration database and frees the handle for future use by the 
computer
system.

Example Program
This program shows how to retrieve the name of the default printer from 
the
Windows 95 registry.

 1. Create a new project in Visual Basic. Form1 is created by default.
 2. Add the following Constant and Declare statements to the General
    Declarations section of Form1 (note that each Declare statement
    must be typed as a single line of code):

Private Declare Function RegOpenKeyEx Lib "advapi32" Alias 
"RegOpenKeyExA"
   (ByVal hKey As Long, ByVal lpSubKey As String, ByVal dwReserved As 
Long,
   ByVal samDesired As Long, phkResult As Long) As Long
Private Declare Function RegQueryValueEx Lib "advapi32" Alias 
"RegQueryValueExA"
   (ByVal hKey As Long, ByVal lpValueName$, ByVal lpdwReserved As Long, 
lpdwType
   As Long, lpData As Any, lpcbData As Long) As Long
Private Declare Function RegCloseKey Lib "advapi32" (ByVal hKey As 
Long) As Long
Const HKEY_CURRENT_CONFIG As Long = &H80000005

 3. Add a Text Box control to Form1. Text1 is created by default.
 4. Add a Command Button control to Form1. Command1 is created by 
default.
 5. Add the following code to the Click event for Command1.

Private Sub Command1_Click()
    Dim PName As String
    PName = GetCurrPrinter()
    Text1.Text = PName
End Sub

 6. Create a new procedure called GetCurrPrinter. Add the following 
code to this
    procedure.

Function GetCurrPrinter() As String
    GetCurrPrinter = RegGetString$(HKEY_CURRENT_CONFIG, 
"System\CurrentControlSet\Control\Print\Printers", "Default")
End Function

 7. Create a new procedure called RegGetString. Add the following code 
to this
    procedure.

Function RegGetString$(hInKey As Long, ByVal subkey$, ByVal valname$)
    Dim RetVal$, hSubKey As Long, dwType As Long, SZ As Long
    Dim R As Long
    RetVal$ = ""
    Const KEY_ALL_ACCESS As Long = &HF0063
    Const ERROR_SUCCESS As Long = 0
    Const REG_SZ As Long = 1
    R = RegOpenKeyEx(hInKey, subkey$, 0, KEY_ALL_ACCESS, hSubKey)
    If R <> ERROR_SUCCESS Then GoTo Quit_Now
    SZ = 256: v$ = String$(SZ, 0)
    R = RegQueryValueEx(hSubKey, valname$, 0, dwType, ByVal v$, SZ)
    If R = ERROR_SUCCESS And dwType = REG_SZ Then
        RetVal$ = Left$(v$, SZ)
    Else
        RetVal$ = "--Not String--"
    End If
    If hInKey = 0 Then R = RegCloseKey(hSubKey)
Quit_Now:
    RegGetString$ = RetVal$
End Function

Run the example program by pressing F5. When you click the Command 
Button control,
the name of your default printer is displayed in the Text Box control.

Additional References
"How to Use the Windows NT Registry in Your Application."
"RegCloseKey." (Development Library, Product Documentation, SDKs,
   Win32 SDK, Win32 Programmer's Reference, Reference, Functions,
   ReadEventLog to RemoveMenu)
"RegOpenKeyEx." (Development Library, Product Documentation, SDKs,
   Win32 SDK, Win32 Programmer's Reference, Reference, Functions,
   ReadEventLog to RemoveMenu)
"RegQueryValueEx." (Development Library, Product Documentation, SDKs,
   Win32 SDK, Win32 Programmer's Reference, Reference, Functions,
   ReadEventLog to RemoveMenu)
"Retrieving Data from the Registry." (Development Library, Product 
Documentation,
   SDKs, Win32 SDK, Win32 Programmer's Reference, Window Management,
   System Services, Registry)