RegistryKey.CreateSubKey Method (String) (Microsoft.Win32)

.NET Framework Class Library

RegistryKey..::.CreateSubKey Method (String)

Creates a new subkey or opens an existing subkey for write access. The string subkey is not case-sensitive.

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

Syntax

Visual Basic (Declaration)

Public Function CreateSubKey ( _
    subkey As String _
) As RegistryKey

Visual Basic (Usage)

Dim instance As RegistryKey
Dim subkey As String
Dim returnValue As RegistryKey

returnValue = instance.CreateSubKey(subkey)

public RegistryKey CreateSubKey(
    string subkey
)

Visual C++

public:
RegistryKey^ CreateSubKey(
    String^ subkey
)

JScript

public function CreateSubKey(
    subkey : String
) : RegistryKey

Parameters

subkey: Type: System..::.String
The name or path of the subkey to create or open.

Return Value

Type: Microsoft.Win32..::.RegistryKey
A RegistryKey object that represents the existing or newly created subkey, or nullNothingnullptra null reference (Nothing in Visual Basic) if the operation failed. If a zero-length string is specified for subkey, the current RegistryKey object is returned.

Exceptions

Exception	Condition
ArgumentNullException	subkey is nullNothingnullptra null reference (Nothing in Visual Basic).
SecurityException	The user does not have the permissions required to create or open the registry key.
ArgumentException	subkey is longer than the maximum length allowed (255 characters).
ObjectDisposedException	The RegistryKey on which this method is being invoked is closed (closed keys cannot be accessed).
UnauthorizedAccessException	The RegistryKey cannot be written to; for example, it was not opened as a writable key , or the user does not have the necessary access rights.
IOException	The nesting level exceeds 510. -or- A system error occurred, such as deletion of the key, or an attempt to create a key in the LocalMachine root.

Remarks

In order to perform this action, the user must have permission at this level and below in the registry hierarchy.

Caution:
Do not expose RegistryKey objects in such a way that a malicious program could create thousands of meaningless subkeys or key/value pairs. For example, do not allow callers to enter arbitrary keys or values.

Examples

The following code example shows how to create a subkey under HKEY_CURRENT_USER, manipulate its contents, and then delete the subkey.

Visual Basic

Imports Microsoft.VisualBasic
Imports System
Imports System.Security.Permissions
Imports Microsoft.Win32

<Assembly: RegistryPermissionAttribute( _
    SecurityAction.RequestMinimum, ViewAndModify := "HKEY_CURRENT_USER")>

Public Class RegKey
    Shared Sub Main()

        ' Create a subkey named Test9999 under HKEY_CURRENT_USER.
        Dim test9999 As RegistryKey = _
            Registry.CurrentUser.CreateSubKey("Test9999")

        ' Create two subkeys under HKEY_CURRENT_USER\Test9999.
        test9999.CreateSubKey("TestName").Close()
        Dim testSettings As RegistryKey = _
            test9999.CreateSubKey("TestSettings")

        ' Create data for the TestSettings subkey.
        testSettings.SetValue("Language", "French")
        testSettings.SetValue("Level", "Intermediate")
        testSettings.SetValue("ID", 123)
        testSettings.Close()

        ' Print the information from the Test9999 subkey.
        Console.WriteLine("There are {0} subkeys under Test9999.", _
            test9999.SubKeyCount.ToString())
        For Each subKeyName As String In test9999.GetSubKeyNames()
            Dim tempKey As RegistryKey = _
                test9999.OpenSubKey(subKeyName)
            Console.WriteLine(vbCrLf & "There are {0} values for " & _
                "{1}.", tempKey.ValueCount.ToString(), tempKey.Name)
            For Each valueName As String In tempKey.GetValueNames()
                Console.WriteLine("{0,-8}: {1}", valueName, _
                    tempKey.GetValue(valueName).ToString())
            Next
        Next

        ' Delete the ID value.
        testSettings = test9999.OpenSubKey("TestSettings", True)
        testSettings.DeleteValue("id")

        ' Verify the deletion.
        Console.WriteLine(CType(testSettings.GetValue( _
            "id", "ID not found."), String))
        testSettings.Close()

        ' Delete or close the new subkey.
        Console.Write(vbCrLf & "Delete newly created " & _
            "registry key? (Y/N) ")
        If Char.ToUpper(Convert.ToChar(Console.Read())) = "Y"C Then
            Registry.CurrentUser.DeleteSubKeyTree("Test9999")
            Console.WriteLine(vbCrLf & "Registry key {0} deleted.", _
                test9999.Name)
        Else
            Console.WriteLine(vbCrLf & "Registry key {0} closed.", _
                test9999.ToString())
            test9999.Close()
        End If

    End Sub
End Class

using System;
using System.Security.Permissions;
using Microsoft.Win32;

[assembly: RegistryPermissionAttribute(SecurityAction.RequestMinimum,
    ViewAndModify = "HKEY_CURRENT_USER")]

class RegKey
{
    static void Main()
    {
        // Create a subkey named Test9999 under HKEY_CURRENT_USER.
        RegistryKey test9999 = 
            Registry.CurrentUser.CreateSubKey("Test9999");
        // Create two subkeys under HKEY_CURRENT_USER\Test9999. The
        // keys are disposed when execution exits the using statement.
        using(RegistryKey 
            testName = test9999.CreateSubKey("TestName"),
            testSettings = test9999.CreateSubKey("TestSettings"))
        {
            // Create data for the TestSettings subkey.
            testSettings.SetValue("Language", "French");
            testSettings.SetValue("Level", "Intermediate");
            testSettings.SetValue("ID", 123);
        }

        // Print the information from the Test9999 subkey.
        Console.WriteLine("There are {0} subkeys under {1}.", 
            test9999.SubKeyCount.ToString(), test9999.Name);
        foreach(string subKeyName in test9999.GetSubKeyNames())
        {
            using(RegistryKey 
                tempKey = test9999.OpenSubKey(subKeyName))
            {
                Console.WriteLine("\nThere are {0} values for {1}.", 
                    tempKey.ValueCount.ToString(), tempKey.Name);
                foreach(string valueName in tempKey.GetValueNames())
                {
                    Console.WriteLine("{0,-8}: {1}", valueName, 
                        tempKey.GetValue(valueName).ToString());
                }
            }
        }

        using(RegistryKey 
            testSettings = test9999.OpenSubKey("TestSettings", true))
        {
            // Delete the ID value.
            testSettings.DeleteValue("id");

            // Verify the deletion.
            Console.WriteLine((string)testSettings.GetValue(
                "id", "ID not found."));
        }

        // Delete or close the new subkey.
        Console.Write("\nDelete newly created registry key? (Y/N) ");
        if(Char.ToUpper(Convert.ToChar(Console.Read())) == 'Y')
        {
            Registry.CurrentUser.DeleteSubKeyTree("Test9999");
            Console.WriteLine("\nRegistry key {0} deleted.", 
                test9999.Name);
        }
        else
        {
            Console.WriteLine("\nRegistry key {0} closed.", 
                test9999.ToString());
            test9999.Close();
        }
    }
}

Visual C++

using namespace System;
using namespace System::Security::Permissions;
using namespace Microsoft::Win32;

[assembly:RegistryPermissionAttribute(SecurityAction::RequestMinimum,
ViewAndModify="HKEY_CURRENT_USER")];
int main()
{
   // Create a subkey named Test9999 under HKEY_CURRENT_USER.
   RegistryKey ^ test9999 = Registry::CurrentUser->CreateSubKey( "Test9999" );

   // Create two subkeys under HKEY_CURRENT_USER\Test9999.
   test9999->CreateSubKey( "TestName" )->Close();
   RegistryKey ^ testSettings = test9999->CreateSubKey( "TestSettings" );

   // Create data for the TestSettings subkey.
   testSettings->SetValue( "Language", "French" );
   testSettings->SetValue( "Level", "Intermediate" );
   testSettings->SetValue( "ID", 123 );
   testSettings->Close();

   // Print the information from the Test9999 subkey.
   Console::WriteLine( "There are {0} subkeys under Test9999.", test9999->SubKeyCount.ToString() );
   array<String^>^subKeyNames = test9999->GetSubKeyNames();
   for ( int i = 0; i < subKeyNames->Length; i++ )
   {
      RegistryKey ^ tempKey = test9999->OpenSubKey( subKeyNames[ i ] );
      Console::WriteLine( "\nThere are {0} values for {1}.", tempKey->ValueCount.ToString(), tempKey->Name );
      array<String^>^valueNames = tempKey->GetValueNames();
      for ( int j = 0; j < valueNames->Length; j++ )
      {
         Console::WriteLine( "{0,-8}: {1}", valueNames[ j ], tempKey->GetValue( valueNames[ j ] )->ToString() );

      }
   }

   // Delete the ID value.
   testSettings = test9999->OpenSubKey( "TestSettings", true );
   testSettings->DeleteValue( "id" );

   // Verify the deletion.
   Console::WriteLine( dynamic_cast<String^>(testSettings->GetValue(  "id", "ID not found." )) );
   testSettings->Close();

   // Delete or close the new subkey.
   Console::Write( "\nDelete newly created registry key? (Y/N) " );
   if ( Char::ToUpper( Convert::ToChar( Console::Read() ) ) == 'Y' )
   {
      Registry::CurrentUser->DeleteSubKeyTree( "Test9999" );
      Console::WriteLine( "\nRegistry key {0} deleted.", test9999->Name );
   }
   else
   {
      Console::WriteLine( "\nRegistry key {0} closed.", test9999->ToString() );
      test9999->Close();
   }
}

.NET Framework Security

RegistryPermission
for the ability to modify the specified registry key if it exists, or for the ability to create the registry key if it does not already exist. Associated enumerations: RegistryPermissionAccess..::.Write, RegistryPermissionAccess..::.Create
SecurityPermission
for the ability to access the specified registry key if it is a remote key. Associated enumeration: SecurityPermissionFlag..::.UnmanagedCode

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

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

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0

Reference

RegistryKey Class

RegistryKey Members

CreateSubKey Overload

Microsoft.Win32 Namespace

DeleteSubKey

OpenSubKey