HOWTO: Retrieve Printer Name from Windows 95/98 Registry in VB

ID: Q143274

The information in this article applies to:

Microsoft Visual Basic Control Creation, Learning, Professional, and Enterprise Editions for Windows, version 5.0
Microsoft Visual Basic Standard, Professional, and Enterprise Editions, 32-bit only, for Windows, version 4.0

SUMMARY

The Registry is used by Windows 95 and Windows 98 to determine what application programs and hardware items are installed in the computer system. This article explains how to retrieve the name of the default printer from the Registry from within a Visual Basic application program.

MORE INFORMATION

Manipulating the Registry in Visual Basic

The Windows 95/98 Registry is a database of information containing configuration details about the hardware and software installed in your computer system. Under Windows 3.1, this information is maintained through initialization (INI) files.

The Registry is comprised of keys. Each key may contain a specific value or other subkeys that in turn may contain values or other subkeys. You can examine or modify the contents of the registration database by using the Win32 Registry API functions in a Visual Basic program or by using the Registry Editor (REGEDIT).

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

The first step to retrieve the printer name is to call the RegOpenKeyEx function. This function opens the specified key in the registration database. In our case, we want to open the key that is associated with the printer. This key is stored in the Registry as:
```
   System
      Current Control Set
         Control
            Print
               Printers
                  Default
 
```
All of the above items are keys and subkeys. We are interested in the Printers subkey.

We also need to tell the RegOpenKeyEx function that we want to work with the Default subkey. After calling this function, a value is returned that is set to zero if the function was successful.

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

The last step is mandatory. You must call the RegCloseKey function to release the handle of the key 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.

How to Create the Demonstration Program

The demonstration program below shows how to retrieve the name of the default printer from the Windows 95 Registry.

Create a new project in Visual Basic. Form1 is created by default.

Add the following constant and Declare statements to the General Declarations section of Form1.


      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

Add a Text Box control to Form1.

Add a Command Button control to Form1.

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

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

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 = &amp;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

Execute the demonstration program by pressing the F5 function key. When you click the Command Button control, the name of your default printer is displayed in the Text Box control.

REFERENCES

Technical Articles, Windows Articles, User Interface Articles. How to Use the Windows NT Registry in Your Application.

Product Documentation, SDKs, Win32 SDK, Win32, Reference, Functions. RegOpenKeyEx QuickInfo Group Overview.

Product Documentation, SDKs, Win32 SDK, Win32, Reference, Functions. RegQueryValueEx QuickInfo Group Overview.

Product Documentation, SDKs, Win32 SDK, Win32, Overviews, System Services, Registry. Retrieving Data from the Registry.

Product Documentation, SDKs, Win32 SDK, Win32, Reference, Functions. RegCloseKey QuickInfo Group Overview.

Additional query words: kbVBp500 kbVBp400 kbAPI kbRegistry kbDSupport kbdsd Kbprint kbVBp600
KBPRINTING KBWIN32SDI


Keywords          : 
Version           : WINDOWS:4.0,5.0
Platform          : WINDOWS 
Issue type        : kbhowto

Last Reviewed: May 13, 1999