Registry.GetValue(String, String, Object) Metode

Referensi

Definisi

Ruang nama:: Microsoft.Win32

Rakitan:: Microsoft.Win32.Registry.dll

Rakitan:: mscorlib.dll

Sumber:: Registry.cs

Penting

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Mengambil nilai yang terkait dengan nama yang ditentukan, dalam kunci registri yang ditentukan. Jika nama tidak ditemukan di kunci yang ditentukan, mengembalikan nilai default yang Anda berikan, atau null jika kunci yang ditentukan tidak ada.

public:
 static System::Object ^ GetValue(System::String ^ keyName, System::String ^ valueName, System::Object ^ defaultValue);

public static object GetValue (string keyName, string valueName, object defaultValue);

public static object? GetValue (string keyName, string? valueName, object? defaultValue);

static member GetValue : string * string * obj -> obj

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

Parameter

keyName: String

Jalur registri lengkap kunci, dimulai dengan akar registri yang valid, seperti "HKEY_CURRENT_USER".

valueName: String

Nama pasangan nama/nilai.

defaultValue: Object

Nilai yang akan dikembalikan jika valueName tidak ada.

Mengembalikan

Object

null jika subkuntangan yang ditentukan oleh keyName tidak ada; jika tidak, nilai yang terkait dengan valueName, atau defaultValue jika valueName tidak ditemukan.

Pengecualian

SecurityException

Pengguna tidak memiliki izin yang diperlukan untuk membaca dari kunci registri.

IOException

RegistryKey yang berisi nilai yang ditentukan telah ditandai untuk penghapusan.

ArgumentException

keyName tidak dimulai dengan akar registri yang valid.

Contoh

Contoh kode berikut menyimpan nilai dari beberapa jenis data dalam contoh kunci, membuat kunci seperti halnya, lalu mengambil dan menampilkan nilai. Contoh menunjukkan penyimpanan dan pengambilan pasangan nama/nilai default (tanpa nama), dan penggunaan defaultValue saat pasangan nama/nilai tidak ada.

using namespace System;
using namespace Microsoft::Win32;

int main()
{   
    // The name of the key must include a valid root.
    String^ userRoot = "HKEY_CURRENT_USER";
    String^ subKey = "RegistrySetValueExample2";
    String^ keyName = String::Concat(userRoot, "\\", subKey);
    
    // An int value can be stored without specifying the
    // registry data type, but Int64 values will be stored
    // as strings unless you specify the type. Note that
    // the int is stored in the default name/value
    // pair.
    Registry::SetValue(keyName, "", 5280);
    Registry::SetValue(keyName, "TestInt64", 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.
    array<String^>^ strings  = {"One", "Two", "Three"};
    Registry::SetValue(keyName, "TestArray", strings);
    
    // Your default value is returned if the name/value pair
    // does not exist.
    String^ noSuch = (String^)Registry::GetValue(keyName, 
        "NoSuchName", 
        "Return this default if NoSuchName does not exist.");
    Console::WriteLine("\r\nNoSuchName: {0}", noSuch);
    
    // Retrieve the int and Int64 values, specifying 
    // numeric default values in case the name/value pairs
    // do not exist. The int value is retrieved from the
    // default (nameless) name/value pair for the key.
    int testInteger = (int)Registry::GetValue(keyName, "", -1);
    Console::WriteLine("(Default): {0}", testInteger);
    long long testInt64 = (long long)Registry::GetValue(keyName, 
        "TestInt64", System::Int64::MinValue);
    Console::WriteLine("TestInt64: {0}", testInt64);
    
    // When retrieving a MultiString value, you can specify
    // an array for the default return value. 
    array<String^>^ testArray = (array<String^>^)Registry::GetValue(
        keyName, "TestArray", 
        gcnew array<String^> {"Default if TestArray does not exist."});
    for (int i = 0; i < testArray->Length; i++)
    {
        Console::WriteLine("TestArray({0}): {1}", i, testArray[i]);
    }
    
    // A string with embedded environment variables is not
    // expanded if it was stored as an ordinary string.
    String^ testExpand = (String^)Registry::GetValue(keyName, 
        "TestExpand", "Default if TestExpand does not exist.");
    Console::WriteLine("TestExpand: {0}", testExpand);
    
    // A string stored as ExpandString is expanded.
    String^ testExpand2 = (String^)Registry::GetValue(keyName, 
        "TestExpand2", "Default if TestExpand2 does not exist.");
    Console::WriteLine(
        "TestExpand2: {0}...", testExpand2->Substring(0, 40));
    Console::WriteLine(
        "\r\nUse the registry editor to examine the key.");
    Console::WriteLine("Press the Enter key to delete the key.");
    Console::ReadLine();
    Registry::CurrentUser->DeleteSubKey(subKey);
}
//
// This code example produces output similar to the following:
//
// NoSuchName: Return this default if NoSuchName does not exist.
// (Default): 5280
// TestInt64: 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.

using System;
using Microsoft.Win32;

public class Example
{
    public static void Main()
    {
        // The name of the key must include a valid root.
        const string userRoot = "HKEY_CURRENT_USER";
        const string subkey = "RegistrySetValueExample";
        const string keyName = userRoot + "\\" + subkey;

        // An int value 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 int 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.
        string[] strings = {"One", "Two", "Three"};
        Registry.SetValue(keyName, "TestArray", strings);

        // Your default value is returned if the name/value pair
        // does not exist.
        string noSuch = (string) Registry.GetValue(keyName,
            "NoSuchName",
            "Return this default if NoSuchName does not exist.");
        Console.WriteLine("\r\nNoSuchName: {0}", noSuch);

        // Retrieve the int and long values, specifying
        // numeric default values in case the name/value pairs
        // do not exist. The int value is retrieved from the
        // default (nameless) name/value pair for the key.
        int tInteger = (int) Registry.GetValue(keyName, "", -1);
        Console.WriteLine("(Default): {0}", tInteger);
        long tLong = (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.
        string[] tArray = (string[]) Registry.GetValue(keyName,
            "TestArray",
            new string[] {"Default if TestArray does not exist."});
        for(int i=0; i<tArray.Length; i++)
        {
            Console.WriteLine("TestArray({0}): {1}", i, tArray[i]);
        }

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

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

        Console.WriteLine("\r\nUse the registry editor to examine the key.");
        Console.WriteLine("Press the Enter key to delete the key.");
        Console.ReadLine();
        Registry.CurrentUser.DeleteSubKey(subkey);
    }
}
//
// 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.

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.

Keterangan

String valueName tidak peka huruf besar/kecil.

Catatan

Kunci registri dapat berisi satu nilai yang tidak terkait dengan nama apa pun. Ketika nilai yang tidak disebutkan namanya ini ditampilkan di editor registri, string "(Default)" muncul alih-alih nama. Untuk mengambil nilai yang tidak disebutkan namanya ini, tentukan salah satu null atau string kosong ("") untuk valueName.

Nama akar yang valid adalah HKEY_CURRENT_USER, HKEY_LOCAL_MACHINE, HKEY_CLASSES_ROOT, HKEY_USERS, HKEY_PERFORMANCE_DATA, HKEY_CURRENT_CONFIG, dan HKEY_DYN_DATA. Misalnya, di Visual Basic untai (karakter) "HKEY_CURRENT_USER\MyTestKey" mengakses pasangan kunci/nilai untuk subkuncar "MyTestKey" di akar HKEY_CURRENT_USER.

GetValue Ketika metode mengambil nilai string yang dapat diperluas (RegistryValueKind.ExpandString), metode ini memperluas string lingkungan menggunakan data dari lingkungan lokal. Jika nilai yang berisi referensi yang dapat diperluas ke variabel lingkungan telah disimpan sebagai string (RegistryValueKind.String), bukan sebagai string yang dapat diperluas (RegistryValueKind.ExpandString), GetValue tidak memperluasnya. Anda dapat memperluas string seperti itu setelah diambil dengan memanggil Environment.ExpandEnvironmentVariables metode .

Catatan

Cara yang disarankan untuk mengambil data dari HKEY_PERFORMANCE_DATA adalah dengan menggunakan PerformanceCounter kelas daripada RegistryKey.GetValue metode .

Metode GetValue dan SetValue membuka dan menutup kunci registri setiap kali digunakan, sehingga tidak berfungsi serta metode RegistryKey kelas jika Anda mengakses sejumlah besar nilai.

RegistryKey juga menyediakan metode yang memungkinkan Anda menambahkan daftar kontrol akses (ACL) ke kunci registri, untuk menguji jenis data nilai sebelum mengambilnya, dan menghapus kunci.

Berlaku untuk

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