Reading from and Writing to the Registry Using the Microsoft.Win32 Namespace

Reading from and Writing to the Reg...

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Microsoft Visual Studio 2008/.NET Framework 3.5

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Visual Basic Application Development

Reading from and Writing to the Registry Using the Microsoft.Win32 Namespace

Although My.Computer.Registry should cover your basic needs when programming against the registry, you can also use the Registry and RegistryKey classes in the Microsoft.Win32 namespace of the .NET Framework.

Keys in the Registry Class

The Registry class supplies the base registry keys that can be used to access subkeys and their values. The base keys themselves are read-only. The following table lists and describes the seven keys exposed by the Registry class.

Key	Description
ClassesRoot	Defines the types of documents and the properties associated with those types.
CurrentConfig	Contains hardware configuration information that is not user-specific.
CurrentUser	Contains information about the current user preferences, such as environmental variables.
DynData	Contains dynamic registry data, such as that used by Virtual Device Drivers.
LocalMachine	Contains five subkeys (Hardware, SAM, Security, Software, and System) that hold the configuration data for the local computer.
PerformanceData	Contains performance information for software components.
Users	Contains information about the default user preferences.

Security Note:
It is more secure to write data to the current user ( CurrentUser) than to the local computer (LocalMachine). A condition that's typically referred to as "squatting" occurs when the key you are creating was previously created by another, possibly malicious, process. To prevent this from occurring, use a method, such as GetValue, that returns Nothing if the key does not already exist.

Reading a Value from the Registry

The following code shows how to read a string from HKEY_CURRENT_USER.

Visual Basic

Dim regVersion As Microsoft.Win32.RegistryKey
Dim keyValue As String
keyValue = "Software\\Microsoft\\TestApp\\1.0"
regVersion = Microsoft.Win32.Registry.CurrentUser.OpenSubKey(keyValue, False)
Dim intVersion As Integer = 0
If (Not regVersion Is Nothing) Then
    intVersion = regVersion.GetValue("Version", 0)
    regVersion.Close()
End If

The following code reads, increments, and then writes a string to HKEY_CURRENT_USER.

Visual Basic

Dim regVersion As Microsoft.Win32.RegistryKey
regVersion = Microsoft.Win32.Registry.CurrentUser.OpenSubKey( _
             "SOFTWARE\\Microsoft\\TestApp\\1.0", True)
If regVersion Is Nothing Then
    ' Key doesn't exist; create it.
    regVersion = Microsoft.Win32.Registry.CurrentUser.CreateSubKey( _
                 "SOFTWARE\\Microsoft\\TestApp\\1.0")
End If

Dim intVersion As Integer = 0
If (Not regVersion Is Nothing) Then
    intVersion = regVersion.GetValue("Version", 0)
    intVersion = intVersion + 1
    regVersion.SetValue("Version", intVersion)
    regVersion.Close()
End If

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