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Registry.GetValue Method

Retrieves the value associated with the specified name, in the specified registry key. If the name is not found in the specified key, returns a default value that you provide, or Nothing if the specified key does not exist.

Namespace:  Microsoft.Win32
Assembly:  mscorlib (in mscorlib.dll)

'Declaration
Public Shared Function GetValue ( _
	keyName As String, _
	valueName As String, _
	defaultValue As Object _
) As Object

Parameters

keyName
Type: System.String
The full registry path of the key, beginning with a valid registry root, such as "HKEY_CURRENT_USER".
valueName
Type: System.String
The name of the name/value pair.
defaultValue
Type: System.Object
The value to return if valueName does not exist.

Return Value

Type: System.Object
Nothing if the subkey specified by keyName does not exist; otherwise, the value associated with valueName, or defaultValue if valueName is not found.

ExceptionCondition
SecurityException

The user does not have the permissions required to read from the registry key.

IOException

The RegistryKey that contains the specified value has been marked for deletion.

ArgumentException

keyName does not begin with a valid registry root.

The string valueName is not case-sensitive.

NoteNote

A registry key can contain one value that is not associated with any name. When this unnamed value is displayed in the registry editor, the string "(Default)" appears instead of a name. To retrieve this unnamed value, specify either Nothing or the empty string ("") for valuName.

Valid root names are HKEY_CURRENT_USER, HKEY_LOCAL_MACHINE, HKEY_CLASSES_ROOT, HKEY_USERS, HKEY_PERFORMANCE_DATA, HKEY_CURRENT_CONFIG, and HKEY_DYN_DATA. For example, in Visual Basic the string "HKEY_CURRENT_USER\MyTestKey" accesses key/value pairs for the subkey "MyTestKey" in the HKEY_CURRENT_USER root.

When the GetValue method retrieves expandable string values (RegistryValueKind.ExpandString), it expands environment strings using data from the local environment. If a value containing expandable references to environment variables has been stored as a string (RegistryValueKind.String), rather than as an expandable string (RegistryValueKind.ExpandString), GetValue does not expand it. You can expand such a string after it has been retrieved by calling the Environment.ExpandEnvironmentVariables method.

NoteNote

The recommended way to retrieve data from HKEY_PERFORMANCE_DATA is to use the PerformanceCounter class rather than the RegistryKey.GetValue method.

The GetValue and SetValue methods open and close registry keys each time they are used, so they do not perform as well as the methods of the RegistryKey class if you access a large number of values.

RegistryKey also provides methods that allow you to add an access control list (ACL) to a registry key, to test the data type of a value before retrieving it, and to delete keys.

The following code example stores values of several data types in an example key, creating the key as it does so, and then retrieves and displays the values. The example demonstrates storing and retrieving the default (nameless) name/value pair, and the use of defaultValue when a name/value pair does not exist.


Imports System
Imports Microsoft.Win32

Public Class Example
    Public Shared Sub Main()
        ' The name of the key must include a valid root.
        Const userRoot As String = "HKEY_CURRENT_USER"
        Const subkey As String = "RegistrySetValueExample"
        Const keyName As String = userRoot & "\" & subkey

        ' Integer values can be stored without specifying the
        ' registry data type, but Long values will be stored
        ' as strings unless you specify the type. Note that
        ' the integer is stored in the default name/value
        ' pair.
        Registry.SetValue(keyName, "", 5280)
        Registry.SetValue(keyName, "TestLong", 12345678901234, _
            RegistryValueKind.QWord)

        ' Strings with expandable environment variables are
        ' stored as ordinary strings unless you specify the
        ' data type.
        Registry.SetValue(keyName, "TestExpand", "My path: %path%")
        Registry.SetValue(keyName, "TestExpand2", "My path: %path%", _
            RegistryValueKind.ExpandString)

        ' Arrays of strings are stored automatically as 
        ' MultiString. Similarly, arrays of Byte are stored
        ' automatically as Binary.
        Dim strings() As String = {"One", "Two", "Three"}
        Registry.SetValue(keyName, "TestArray", strings)

        ' Your default value is returned if the name/value pair
        ' does not exist.
        Dim noSuch As String = _
            Registry.GetValue(keyName, "NoSuchName", _
            "Return this default if NoSuchName does not exist.")
        Console.WriteLine(vbCrLf & "NoSuchName: {0}", noSuch)

        ' Retrieve the Integer and Long values, specifying 
        ' numeric default values in case the name/value pairs
        ' do not exist. The Integer value is retrieved from the
        ' default (nameless) name/value pair for the key.
        Dim tInteger As Integer = _
            Registry.GetValue(keyName, "", -1)
        Console.WriteLine("(Default): {0}", tInteger)
        Dim tLong As Long = Registry.GetValue(keyName, _
             "TestLong", Long.MinValue)
        Console.WriteLine("TestLong: {0}", tLong)

        ' When retrieving a MultiString value, you can specify
        ' an array for the default return value. The value is
        ' declared inline, but could also be declared as:
        ' Dim default() As String = {"Default value."}
        '
        Dim tArray() As String = _
            Registry.GetValue(keyName, "TestArray", _
            New String() {"Default if TestArray does not exist."})
        For i As Integer = 0 To tArray.Length - 1
            Console.WriteLine("TestArray({0}): {1}", i, tArray(i))
        Next

        ' A string with embedded environment variables is not
        ' expanded if it was stored as an ordinary string.
        Dim tExpand As String = Registry.GetValue(keyName, _
             "TestExpand", "Default if TestExpand does not exist.")
        Console.WriteLine("TestExpand: {0}", tExpand)

        ' A string stored as ExpandString is expanded.
        Dim tExpand2 As String = Registry.GetValue(keyName, _
             "TestExpand2", "Default if TestExpand2 does not exist.")
        Console.WriteLine("TestExpand2: {0}...", _
            tExpand2.Substring(0, 40))

        Console.WriteLine(vbCrLf & _
            "Use the registry editor to examine the key.")
        Console.WriteLine("Press the Enter key to delete the key.")
        Console.ReadLine()
        Registry.CurrentUser.DeleteSubKey(subkey)
    End Sub
End Class
'
' This code example produces output similar to the following:
'
'NoSuchName: Return this default if NoSuchName does not exist.
'(Default): 5280
'TestLong: 12345678901234
'TestArray(0): One
'TestArray(1): Two
'TestArray(2): Three
'TestExpand: My path: %path%
'TestExpand2: My path: D:\Program Files\Microsoft.NET\...
'
'Use the registry editor to examine the key.
'Press the Enter key to delete the key.


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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