[VB] Registry Operations

A central hierarchical database used in Microsoft Windows Operating System to store information that is necessary to configure the system for one or more users, applications and hardware devices.

The Registry comprises a number of logical sections called Hives. The following are the predefined keys that are used by the system.

• HKEY_CURRENT_USER
• HKEY_USERS
• HKEY_LOCAL_MACHINE
• HKEY_CLASSES_ROOT
• HKEY_CURRENT_CONFIG

Each key has many subkeys and may have a value.

When programming with VB.NET, you can choose to access the registry via either the functions provided by VB.NET or the registry classes of the .NET Framework. Registry entries contain two parts: the value name and the value.

Creating a Registry Entry

rKey = Registry.LocalMachine.OpenSubKey("SOFTWARE", True)
rKey.CreateSubKey("AppReg")

Above code shows how to create a subkey under HKLM\Software called AppReg.

Writing values to Registry

 
rKey.SetValue("AppName", "RegApp")
rKey.SetValue("Version", 1.1)

Above code shows how to set values to registry entry AppReg.

The following VB.NET program shows how to create a registry entry , set values to registry , retrieve values from registry and delete keys on Registry.Drag and drop four buttons on the form control and copy and paste the following source code.

FULL CODE EXAMPLTE :

Imports Microsoft.Win32
Public Class Form1

	Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
		Dim rKey As RegistryKey
		rKey = Registry.LocalMachine.OpenSubKey("SOFTWARE", True)
		rKey.CreateSubKey("AppReg")
		rKey.Close()
		MsgBox("AppReg created !")
	End Sub

	Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
		Dim rKey As RegistryKey
		rKey = Registry.LocalMachine.OpenSubKey("Software\AppReg", True)
		rKey.SetValue("AppName", "RegApp")
		rKey.SetValue("Version", 1.1)
		rKey.Close()
		MsgBox("Appname , version created")
	End Sub

	Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
		Dim rKey As RegistryKey
		Dim ver As Decimal
		Dim app As String
		rKey = Registry.LocalMachine.OpenSubKey("Software\AppReg", True)
		app = rKey.GetValue("AppName")
		ver = rKey.GetValue("Version")
		rKey.Close()
		MsgBox("App Name  " & app & "  Version  " & ver.ToString)
	End Sub

	Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
		Dim rKey As RegistryKey
		rKey = Registry.LocalMachine.OpenSubKey("Software", True)
		rKey.DeleteSubKey("AppReg", True)
		rKey.Close()
		MsgBox("AppReg deleted")
	End Sub
End Class