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.NET Development
.NET Framework 3.5
Registry Class
Registry Fields
 ClassesRoot Field
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This page is specific to
Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:
.NET Framework Class Library
Registry..::.ClassesRoot Field

Defines the types (or classes) of documents and the properties associated with those types. This field reads the Windows registry base key HKEY_CLASSES_ROOT.

Namespace:  Microsoft.Win32
Assembly:  mscorlib (in mscorlib.dll)
Visual Basic (Declaration)
Public Shared ReadOnly ClassesRoot As RegistryKey
Visual Basic (Usage)
Dim value As RegistryKey

value = Registry.ClassesRoot
C#
public static readonly RegistryKey ClassesRoot
Visual C++
public:
static initonly RegistryKey^ ClassesRoot
JScript
public static final var ClassesRoot : RegistryKey

Both conventional applications and OLE applications use data that is stored under this key. This key also provides backward compatibility with the Windows 3.1 registration database by storing information for DDE and OLE support. File viewers and user interface extensions store their OLE class identifiers in this key, and processing servers are registered in this key.

The following example demonstrates how to retrieve the subkeys of this key, and prints their names to the screen. Use the OpenSubKey method to create an instance of the particular subkey of interest. You can then use other operations in RegistryKey to manipulate that key.

Visual Basic
Imports System
Imports Microsoft.Win32

Class Reg

    Public Shared Sub Main()

        ' Create a RegistryKey, which will access the HKEY_CLASSES_ROOT
        ' key in the registry of this machine.
        Dim rk As RegistryKey = Registry.ClassesRoot

        ' Print out the keys.
        PrintKeys(rk)
    End Sub    

    Shared Sub PrintKeys(rkey As RegistryKey)

        ' Retrieve all the subkeys for the specified key.
        Dim names As String() = rkey.GetSubKeyNames()

        Dim icount As Integer = 0

        Console.WriteLine("Subkeys of " & rkey.Name)
        Console.WriteLine("-----------------------------------------------")

        ' Print the contents of the array to the console.
        Dim s As String
        For Each s In  names
            Console.WriteLine(s)

            ' The following code puts a limit on the number
            ' of keys displayed.  Comment it out to print the
            ' complete list.
            icount += 1            
            If icount >= 10 Then
                Exit For
            End If
        Next s
    End Sub
End Class
C#
using System;
using Microsoft.Win32;

class Reg {
    public static void Main() {

        // Create a RegistryKey, which will access the HKEY_CLASSES_ROOT
        // key in the registry of this machine.
        RegistryKey rk = Registry.ClassesRoot;

        // Print out the keys.
        PrintKeys(rk);
    }

    static void PrintKeys(RegistryKey rkey) {

        // Retrieve all the subkeys for the specified key.
        String [] names = rkey.GetSubKeyNames();

        int icount = 0;

        Console.WriteLine("Subkeys of " + rkey.Name);
        Console.WriteLine("-----------------------------------------------");

        // Print the contents of the array to the console.
        foreach (String s in names) {
            Console.WriteLine(s);

            // The following code puts a limit on the number
            // of keys displayed.  Comment it out to print the
            // complete list.
            icount++;
            if (icount >= 10)
                break;
        }
    }
}
Visual C++
using namespace System;
using namespace Microsoft::Win32;
void PrintKeys( RegistryKey ^ rkey )
{

   // Retrieve all the subkeys for the specified key.
   array<String^>^names = rkey->GetSubKeyNames();
   int icount = 0;
   Console::WriteLine( "Subkeys of {0}", rkey->Name );
   Console::WriteLine( "-----------------------------------------------" );

   // Print the contents of the array to the console.
   System::Collections::IEnumerator^ enum0 = names->GetEnumerator();
   while ( enum0->MoveNext() )
   {
      String^ s = safe_cast<String^>(enum0->Current);
      Console::WriteLine( s );

      // The following code puts a limit on the number
      // of keys displayed.  Comment it out to print the
      // complete list.
      icount++;
      if ( icount >= 10 )
            break;
   }
}

int main()
{

   // Create a RegistryKey, which will access the HKEY_CLASSES_ROOT
   // key in the registry of this machine.
   RegistryKey ^ rk = Registry::ClassesRoot;

   // Print out the keys.
   PrintKeys( rk );
}

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.

.NET Framework

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

.NET Compact Framework

Supported in: 3.5, 2.0
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