Accessing the Registry with VB6 and VB.NET

Storing and retrieving information from the Windows Registry will play a major part in any programmer's life. You can store small bits of information, such as recently used files, form sizes and location, and user preferences—to name just a few—in the Windows Registry. My aim with this article is to explain the major differences between the way Visual Basic 6 and Visual Basic .NET utilise the Windows Registry.

Visual Basic 6 and the Windows Registry

Visual Basic 6 comes with four procedures for accessing the Windows Registry:

• SaveSetting
• GetSetting
• GetAllSettings
• DeleteSetting

SaveSetting

The SaveSetting statement is used to store a value in the Registry.

Syntax

SaveSetting VBKeyName, Section, Key, Setting

Term	Meaning
SaveSetting	Statement name
VBKeyName	String value representing the name of the key within the VB/VBA area of the Registry
Section	String value representing the section or subkey for the specific application's setting
Key	String value that represents the name of a specific entry within the section
Setting	String value that you want to store to a given key

Example

'Store Left Value
SaveSetting App.Title, "Form Location", "Left", "250"
'Store Top Value
SaveSetting App.Title, "Form Location", "Top", "300"

GetSetting

You use the GetSetting() function to retrieve a value from a particular section in the Visual Basic key of the Windows Registry.

Syntax

Term	Meaning
StringVariable	String value returned by the GetSetting() function
GetSetting	The name of the function
VBKeyName	String value representing the name of the key within the VB/VBA area of the Registry
Section	String value representing the section or subkey for the specific applications setting
Key	String value that represents the name of a specific entry within the section
Default	Optional argument. A String value that represents the value to return if GetSetting() fails or encounters an error. If the function is successful, it returns the string found at the key setting; if it is unsuccessful, it returns the string value assigned to the Default argument

Example

'Variable to hold value returned from the Registry
Dim strTop As String
'Variable to hold value returned from Registry
Dim strLeft As String
'Read Top value stored
strTop = GetSetting(App.Title, "Form Location", "Top")
'Read Left value stored
strLeft = GetSetting(App.Title, "Form Location", "Left")

GetAllSettings

You use GetAllSettings() to retrieve an array from the Registry that contains all the key settings along with their respective values of a particular section in the Registry.

Syntax

VariantVariable = GetAllSettings(VBKeyName, Section)

Term	Meaning
VariantVariable	An array of values returned by the function, of type Variant
GetAllSettings	Function name
VBKeyName	String value representing the name of the key within the VB/VBA area of the Registry
Section	String value that represents the name of a specific entry within the section

Example

Dim arrAllSettings As Variant    'Variable to store 2 dimensional
                                 'array of values read from the
                                 'Registry

'Retrieve Registry values stored under Form Location
arrAllSettings = GetAllSettings(App.Title, "Form Location")


'Display the first key and first value under Form Location (Left)
txtGetAllSettings.Text = arrAllSettings(0, 0) & " = " & _
   arrAllSettings(0, 1) & vbCrLf
'Display the second key and second value under Form Location (Top)
txtGetAllSettings.Text = txtGetAllSettings.Text & _
   arrAllSettings(1, 0) _
   & " = " & arrAllSettings(1, 1)

DeleteSetting

If you want to delete an entire section from a key, you use the DeleteSetting statement.

Syntax

DeleteSetting VBKeyName, Section [, Key]

Term	Meaning
DeleteSetting	Statement name
VBKeyName	String value representing the name of the key within the VB/VBA area of the Registry
Section	String Value representing the section to delete
Key	String Value representing a specific subkey to delete. If you do not supply this optional paramater, all the subkeys of the section will be deleted

Example

DeleteSetting App.Title, "Form Location" 'Delete Form Location

These internal Registry functions have one major drawback. Visual Basic can retrieve and store data only to a specific key in the Registry, namely:

MyComputer\HKEY_CURRENT_USER\Software\VB and VBA Program Settings

This process is, unfortunately, automatic to Visual Basic 6; Visual Basic 6 cannot write to or read from any other keys in the Windows Registry without the aid of the Windows API, functions such as:

• RegOpenKey
• RegOpenKeyEx
• RegCreateKey
• RegCreateKeyEx
• RegDeleteKey
• RegCloseKey
• RegQueryValueEx
• RegSetValueEx
• RegDeleteValue
• RegEnumKeyEx
• RegEnumValue
• RegRestoreKey
• RegSaveKey

Sample Application

The first sample application (RegistryVB6) accompanying this article shows in detail how the intrinsic Visual Basic 6 Registry functions are used to store and retrieve values in the Registry. The sample application also shows in detail how to use the necessary API functions to store values in the Registry and read from the Registry.

On the next page, I will explain how Visual Basic.NET accesses the Windows Registry.

Hannes du Preez is a Microsoft MVP for Visual Basic. He is a trainer at a South African-based company. He is the co-founder of hmsmp.co.za, a community for South African developers.