RegistryKey.OpenSubKey Método

public:
 Microsoft::Win32::RegistryKey ^ OpenSubKey(System::String ^ name, bool writable);

public Microsoft.Win32.RegistryKey OpenSubKey(string name, bool writable);

member this.OpenSubKey : string * bool -> Microsoft.Win32.RegistryKey

Public Function OpenSubKey (name As String, writable As Boolean) As RegistryKey

Parâmetros

Devoluções

A subchave solicitada, ou null se a operação falhasse.

Exceções

Exemplos

O exemplo de código seguinte cria uma chave de teste e usa o OpenSubKey método para a abrir, demonstrando ambas as sobrecargas do método.

#using <Microsoft.VisualBasic.dll>

using namespace System;
using namespace Microsoft::Win32;
using namespace Microsoft::VisualBasic;

int main()
{
    // Delete and recreate the test key.
    Registry::CurrentUser->DeleteSubKey( L"RegistryOpenSubKeyExample", false );
    RegistryKey ^ rk = Registry::CurrentUser->CreateSubKey( L"RegistryOpenSubKeyExample" );
    rk->Close();

    // Obtain an instance of RegistryKey for the CurrentUser registry
    // root.
    RegistryKey ^ rkCurrentUser = Registry::CurrentUser;

    // Obtain the test key (read-only) and display it.
    RegistryKey ^ rkTest = rkCurrentUser->OpenSubKey( L"RegistryOpenSubKeyExample" );
    Console::WriteLine( L"Test key: {0}", rkTest );
    rkTest->Close();
    rkCurrentUser->Close();

    // Obtain the test key in one step, using the CurrentUser registry
    // root.
    rkTest = Registry::CurrentUser->OpenSubKey( L"RegistryOpenSubKeyExample" );
    Console::WriteLine( L"Test key: {0}", rkTest );
    rkTest->Close();

    // Open the test key in read/write mode.
    rkTest = Registry::CurrentUser->OpenSubKey( L"RegistryOpenSubKeyExample", true );
    rkTest->SetValue( L"TestName", L"TestValue" );
    Console::WriteLine( L"Test value for TestName: {0}", rkTest->GetValue( L"TestName" ) );
    rkTest->Close();

    return 0;
} //Main

using System;
using Microsoft.Win32;
using Microsoft.VisualBasic;

public class Example
{
    public static void Main()
    {
        // Delete and recreate the test key.
        Registry.CurrentUser.DeleteSubKey("RegistryOpenSubKeyExample", false);
        RegistryKey rk = Registry.CurrentUser.CreateSubKey("RegistryOpenSubKeyExample");
        rk.Close();

        // Obtain an instance of RegistryKey for the CurrentUser registry
        // root.
        RegistryKey rkCurrentUser = Registry.CurrentUser;

        // Obtain the test key (read-only) and display it.
        RegistryKey rkTest = rkCurrentUser.OpenSubKey("RegistryOpenSubKeyExample");
        Console.WriteLine("Test key: {0}", rkTest);
        rkTest.Close();
        rkCurrentUser.Close();

        // Obtain the test key in one step, using the CurrentUser registry
        // root.
        rkTest = Registry.CurrentUser.OpenSubKey("RegistryOpenSubKeyExample");
        Console.WriteLine("Test key: {0}", rkTest);
        rkTest.Close();

        // Open the test key in read/write mode.
        rkTest = Registry.CurrentUser.OpenSubKey("RegistryOpenSubKeyExample", true);
        rkTest.SetValue("TestName", "TestValue");
        Console.WriteLine("Test value for TestName: {0}", rkTest.GetValue("TestName"));
        rkTest.Close();
    } //Main
} //Example

Imports Microsoft.Win32

Public Class Example
    Public Shared Sub Main()
        ' Delete and recreate the test key.
        Registry.CurrentUser.DeleteSubKey("RegistryOpenSubKeyExample", False)
        Dim rk As RegistryKey = Registry.CurrentUser.CreateSubKey("RegistryOpenSubKeyExample")
        rk.Close

        ' Obtain an instance of RegistryKey for the CurrentUser registry 
        ' root. 
        Dim rkCurrentUser As RegistryKey = Registry.CurrentUser

        ' Obtain the test key (read-only) and display it.
        Dim rkTest As RegistryKey = rkCurrentUser.OpenSubKey("RegistryOpenSubKeyExample")
        Console.WriteLine("Test key: {0}", rkTest)
        rkTest.Close
        rkCurrentUser.Close

        ' Obtain the test key in one step, using the CurrentUser registry 
        ' root.
        rkTest = Registry.CurrentUser.OpenSubKey("RegistryOpenSubKeyExample")
        Console.WriteLine("Test key: {0}", rkTest)
        rkTest.Close

        ' Obtain the test key in read/write mode.
        rkTest = Registry.CurrentUser.OpenSubKey("RegistryOpenSubKeyExample", True)
        rkTest.SetValue("TestName", "TestValue")
        Console.WriteLine("Test value for TestName: {0}", rkTest.GetValue("TestName"))
        rkTest.Close
    End Sub
End Class

Observações

Se a chave solicitada não existir, este método devolve null em vez de lançar uma exceção.

Se writable for true, a chave será aberta para leitura e escrita, caso contrário, a chave será aberta apenas para leitura.

Para usar o OpenSubKey método, deve ter uma instância do mesmo RegistryKey . Para obter uma instância de RegistryKey, use um dos membros estáticos da Registry classe.

Ver também

• CreateSubKey(String)
• DeleteSubKey(String)
• DeleteSubKeyTree(String)
• GetSubKeyNames()
• OpenRemoteBaseKey(RegistryHive, String)
• SubKeyCount
• Registry

public:
 Microsoft::Win32::RegistryKey ^ OpenSubKey(System::String ^ name, Microsoft::Win32::RegistryKeyPermissionCheck permissionCheck, System::Security::AccessControl::RegistryRights rights);

[System.Runtime.InteropServices.ComVisible(false)]
public Microsoft.Win32.RegistryKey OpenSubKey(string name, Microsoft.Win32.RegistryKeyPermissionCheck permissionCheck, System.Security.AccessControl.RegistryRights rights);

[<System.Runtime.InteropServices.ComVisible(false)>]
member this.OpenSubKey : string * Microsoft.Win32.RegistryKeyPermissionCheck * System.Security.AccessControl.RegistryRights -> Microsoft.Win32.RegistryKey

Public Function OpenSubKey (name As String, permissionCheck As RegistryKeyPermissionCheck, rights As RegistryRights) As RegistryKey

Parâmetros

Devoluções

A subchave solicitada, ou null se a operação falhasse.

Atributos

ComVisibleAttribute

Exceções

Observações

Em vez de lançar uma exceção, este método retorna null se a chave solicitada não existir.

Se permissionCheck for RegistryKeyPermissionCheck.ReadWriteSubTree, a chave é aberta para leitura e escrita; se permissionCheck for RegistryKeyPermissionCheck.ReadSubTree ou RegistryKeyPermissionCheck.Default, a chave é aberta para leitura, a menos que a chave pai tenha sido aberta com RegistryKeyPermissionCheck.ReadWriteSubTree.

O acesso especificado para permissionCheck tem precedência sobre o acesso especificado para rights. Por exemplo, se especificar RegistryKeyPermissionCheck.ReadSubTree para permissionCheck e RegistryRights.WriteKey para rights, uma tentativa de escrever na subchave lança uma exceção.

Para usar o OpenSubKey método, deve ter uma instância da RegistryKey classe. Para obter uma instância de RegistryKey, use um dos membros estáticos da Registry classe.

Ver também

• CreateSubKey(String)
• DeleteSubKey(String)
• DeleteSubKeyTree(String)
• GetSubKeyNames()
• OpenRemoteBaseKey(RegistryHive, String)
• SubKeyCount
• Registry

public:
 Microsoft::Win32::RegistryKey ^ OpenSubKey(System::String ^ name, System::Security::AccessControl::RegistryRights rights);

[System.Runtime.InteropServices.ComVisible(false)]
public Microsoft.Win32.RegistryKey OpenSubKey(string name, System.Security.AccessControl.RegistryRights rights);

[<System.Runtime.InteropServices.ComVisible(false)>]
member this.OpenSubKey : string * System.Security.AccessControl.RegistryRights -> Microsoft.Win32.RegistryKey

Public Function OpenSubKey (name As String, rights As RegistryRights) As RegistryKey

Parâmetros

Devoluções

A subchave solicitada, ou null se a operação falhasse.

Atributos

ComVisibleAttribute

Exceções

Observações

Deve abrir uma chave antes que possa ser manipulada com outros métodos e propriedades. Para modificar uma chave, deve abri-la com uma sobrecarga do OpenSubKey método que permite especificar o acesso de escrita.

public:
 Microsoft::Win32::RegistryKey ^ OpenSubKey(System::String ^ name);

public Microsoft.Win32.RegistryKey OpenSubKey(string name);

member this.OpenSubKey : string -> Microsoft.Win32.RegistryKey

Public Function OpenSubKey (name As String) As RegistryKey

Parâmetros

Devoluções

A subchave solicitada, ou null se a operação falhasse.

Exceções

Exemplos

O exemplo de código seguinte cria uma chave de teste e usa o OpenSubKey método para a abrir, demonstrando ambas as sobrecargas do método.

#using <Microsoft.VisualBasic.dll>

using namespace System;
using namespace Microsoft::Win32;
using namespace Microsoft::VisualBasic;

int main()
{
    // Delete and recreate the test key.
    Registry::CurrentUser->DeleteSubKey( L"RegistryOpenSubKeyExample", false );
    RegistryKey ^ rk = Registry::CurrentUser->CreateSubKey( L"RegistryOpenSubKeyExample" );
    rk->Close();

    // Obtain an instance of RegistryKey for the CurrentUser registry
    // root.
    RegistryKey ^ rkCurrentUser = Registry::CurrentUser;

    // Obtain the test key (read-only) and display it.
    RegistryKey ^ rkTest = rkCurrentUser->OpenSubKey( L"RegistryOpenSubKeyExample" );
    Console::WriteLine( L"Test key: {0}", rkTest );
    rkTest->Close();
    rkCurrentUser->Close();

    // Obtain the test key in one step, using the CurrentUser registry
    // root.
    rkTest = Registry::CurrentUser->OpenSubKey( L"RegistryOpenSubKeyExample" );
    Console::WriteLine( L"Test key: {0}", rkTest );
    rkTest->Close();

    // Open the test key in read/write mode.
    rkTest = Registry::CurrentUser->OpenSubKey( L"RegistryOpenSubKeyExample", true );
    rkTest->SetValue( L"TestName", L"TestValue" );
    Console::WriteLine( L"Test value for TestName: {0}", rkTest->GetValue( L"TestName" ) );
    rkTest->Close();

    return 0;
} //Main

using System;
using Microsoft.Win32;
using Microsoft.VisualBasic;

public class Example
{
    public static void Main()
    {
        // Delete and recreate the test key.
        Registry.CurrentUser.DeleteSubKey("RegistryOpenSubKeyExample", false);
        RegistryKey rk = Registry.CurrentUser.CreateSubKey("RegistryOpenSubKeyExample");
        rk.Close();

        // Obtain an instance of RegistryKey for the CurrentUser registry
        // root.
        RegistryKey rkCurrentUser = Registry.CurrentUser;

        // Obtain the test key (read-only) and display it.
        RegistryKey rkTest = rkCurrentUser.OpenSubKey("RegistryOpenSubKeyExample");
        Console.WriteLine("Test key: {0}", rkTest);
        rkTest.Close();
        rkCurrentUser.Close();

        // Obtain the test key in one step, using the CurrentUser registry
        // root.
        rkTest = Registry.CurrentUser.OpenSubKey("RegistryOpenSubKeyExample");
        Console.WriteLine("Test key: {0}", rkTest);
        rkTest.Close();

        // Open the test key in read/write mode.
        rkTest = Registry.CurrentUser.OpenSubKey("RegistryOpenSubKeyExample", true);
        rkTest.SetValue("TestName", "TestValue");
        Console.WriteLine("Test value for TestName: {0}", rkTest.GetValue("TestName"));
        rkTest.Close();
    } //Main
} //Example

Imports Microsoft.Win32

Public Class Example
    Public Shared Sub Main()
        ' Delete and recreate the test key.
        Registry.CurrentUser.DeleteSubKey("RegistryOpenSubKeyExample", False)
        Dim rk As RegistryKey = Registry.CurrentUser.CreateSubKey("RegistryOpenSubKeyExample")
        rk.Close

        ' Obtain an instance of RegistryKey for the CurrentUser registry 
        ' root. 
        Dim rkCurrentUser As RegistryKey = Registry.CurrentUser

        ' Obtain the test key (read-only) and display it.
        Dim rkTest As RegistryKey = rkCurrentUser.OpenSubKey("RegistryOpenSubKeyExample")
        Console.WriteLine("Test key: {0}", rkTest)
        rkTest.Close
        rkCurrentUser.Close

        ' Obtain the test key in one step, using the CurrentUser registry 
        ' root.
        rkTest = Registry.CurrentUser.OpenSubKey("RegistryOpenSubKeyExample")
        Console.WriteLine("Test key: {0}", rkTest)
        rkTest.Close

        ' Obtain the test key in read/write mode.
        rkTest = Registry.CurrentUser.OpenSubKey("RegistryOpenSubKeyExample", True)
        rkTest.SetValue("TestName", "TestValue")
        Console.WriteLine("Test value for TestName: {0}", rkTest.GetValue("TestName"))
        rkTest.Close
    End Sub
End Class

Observações

Deve abrir uma chave antes que possa ser manipulada com outros métodos e propriedades. Para modificar uma chave, deve abri-la com uma sobrecarga do OpenSubKey método que permite especificar o acesso de escrita, como a OpenSubKey(String, RegistryKeyPermissionCheck) sobrecarga ou a OpenSubKey(String, Boolean) sobrecarga.

Se a subchave especificada não for encontrada, então null é devolvida.

Para usar o OpenSubKey método, deve ter uma instância de RegistryKey. Para obter uma instância de RegistryKey, use um dos membros estáticos da Registry classe.

Ver também

• CreateSubKey(String)
• DeleteSubKey(String)
• DeleteSubKeyTree(String)
• GetSubKeyNames()
• OpenRemoteBaseKey(RegistryHive, String)
• SubKeyCount
• Registry

public:
 Microsoft::Win32::RegistryKey ^ OpenSubKey(System::String ^ name, Microsoft::Win32::RegistryKeyPermissionCheck permissionCheck);

[System.Runtime.InteropServices.ComVisible(false)]
public Microsoft.Win32.RegistryKey OpenSubKey(string name, Microsoft.Win32.RegistryKeyPermissionCheck permissionCheck);

[<System.Runtime.InteropServices.ComVisible(false)>]
member this.OpenSubKey : string * Microsoft.Win32.RegistryKeyPermissionCheck -> Microsoft.Win32.RegistryKey

Public Function OpenSubKey (name As String, permissionCheck As RegistryKeyPermissionCheck) As RegistryKey

Parâmetros

Devoluções

A subchave solicitada, ou null se a operação falhasse.

Atributos

ComVisibleAttribute

Exceções

Exemplos

O seguinte exemplo de código cria uma subchave contendo 100 pares chave/valor e fecha-a. O exemplo abre a subchave com Default, regista o tempo que demora a ler todos os valores e fecha a subchave. O exemplo abre a subchave com ReadSubTree e regista o tempo que demora a ler todos os valores. Por fim, o exemplo calcula e mostra a percentagem de melhoria.

using System;
using Microsoft.Win32;
using System.Diagnostics;

public class Example
{
    public static void Main()
    {
        const int LIMIT = 100;
        RegistryKey cu = Registry.CurrentUser;
        const string testKey = "RegistryKeyPermissionCheckExample";

        Console.WriteLine("Generating {0} key/value pairs.", LIMIT);
        RegistryKey rk = cu.CreateSubKey(testKey);
        for (int i = 0; i < LIMIT; i++)
        {
            rk.SetValue("Key" + i, i);
        }

        rk.Close();

        Stopwatch s = new Stopwatch();

        // On the default setting, security is checked every time
        // a key/value pair is read.
        rk = cu.OpenSubKey(testKey, RegistryKeyPermissionCheck.Default);

        s.Start();
        for (int i = 0; i < LIMIT; i++)
        {
            rk.GetValue("Key" + i, i);
        }
        s.Stop();
        rk.Close();
        long delta1 = s.ElapsedTicks;

        s.Reset();

        // When the key is opened with ReadSubTree, security is
        // not checked when the values are read.
        rk = cu.OpenSubKey(testKey, RegistryKeyPermissionCheck.ReadSubTree);

        s.Start();
        for (int i = 0; i < LIMIT; i++)
        {
            rk.GetValue("Key" + i, i);
        }
        s.Stop();
        rk.Close();
        long delta2 = s.ElapsedTicks;

        double faster = (double) (delta1 - delta2) / (double) delta1;
        Console.WriteLine("ReadSubTree is {0}% faster for {1} values.",
            (faster * 100).ToString("0.0"), LIMIT);

        cu.DeleteSubKey(testKey);
    }
}

/* This code example produces output similar to the following:

Generating 100 key/value pairs.
ReadSubTree is 23.4% faster for 100 values.
 */

Imports Microsoft.Win32
Imports System.Diagnostics

Public Class Example
    
    Public Shared Sub Main() 

        Const LIMIT As Integer = 100
        Dim cu As RegistryKey = Registry.CurrentUser
        Const testKey As String = "RegistryKeyPermissionCheckExample"
        
        Console.WriteLine("Generating {0} key/value pairs.", LIMIT)
        Dim rk As RegistryKey = cu.CreateSubKey(testKey)

        For i As Integer = 0 To LIMIT
            rk.SetValue("Key" & i, i)
        Next i
        
        rk.Close()
        
        Dim s As New Stopwatch()
        
        ' On the default setting, security is checked every time
        ' a key/value pair is read.
        rk = cu.OpenSubKey(testKey, _
            RegistryKeyPermissionCheck.Default)
        
        s.Start()
        For i As Integer = 0 To LIMIT
            rk.GetValue("Key" & i, i)
        Next i
        s.Stop()
        rk.Close()
        Dim delta1 As Long = s.ElapsedTicks
        
        s.Reset()
        
        ' When the key is opened with ReadSubTree, security is 
        ' not checked when the values are read.
        rk = cu.OpenSubKey(testKey, _
            RegistryKeyPermissionCheck.ReadSubTree)
        
        s.Start()
        For i As Integer = 0 To LIMIT
            rk.GetValue("Key" & i, i)
        Next i
        s.Stop()
        rk.Close()
        Dim delta2 As Long = s.ElapsedTicks
        
        Dim faster As Double = _
            CDbl(delta1 - delta2) * 100.0 / CDbl(delta1)
        Console.WriteLine("ReadSubTree is {0}% faster for {1} values.", _
            faster.ToString("0.0"), LIMIT)
        
        cu.DeleteSubKey(testKey)
    
    End Sub 
End Class 

' This code example produces output similar to the following:
'
'Generating 100 key/value pairs.
'ReadSubTree is 23.4% faster for 100 values.
'

Observações

Em vez de lançar uma exceção, este método retorna null se a chave solicitada não existir.

Se permissionCheck for RegistryKeyPermissionCheck.ReadWriteSubTree, a chave é aberta para leitura e escrita; se permissionCheck for RegistryKeyPermissionCheck.ReadSubTree ou RegistryKeyPermissionCheck.Default, a chave é aberta para leitura, a menos que a chave pai tenha sido aberta com RegistryKeyPermissionCheck.ReadWriteSubTree.

Para usar o OpenSubKey método, deve ter uma instância da RegistryKey classe. Para obter uma instância de RegistryKey, use um dos membros estáticos da Registry classe.

Ver também

• CreateSubKey(String)
• DeleteSubKey(String)
• DeleteSubKeyTree(String)
• GetSubKeyNames()
• OpenRemoteBaseKey(RegistryHive, String)
• SubKeyCount
• Registry