SecureString.Clear Méthode
Définition
Important
Certaines informations portent sur la préversion du produit qui est susceptible d’être en grande partie modifiée avant sa publication. Microsoft exclut toute garantie, expresse ou implicite, concernant les informations fournies ici.
Supprime la valeur de la chaîne sécurisée actuelle.
public:
void Clear();
public void Clear ();
member this.Clear : unit -> unit
Public Sub Clear ()
Exceptions
Cette chaîne sécurisée a déjà été supprimée.
Cette chaîne sécurisée est en lecture seule.
Exemples
L’exemple suivant montre comment les AppendCharméthodes , InsertAt, RemoveAt, SetAtet Clear affectent la valeur d’un SecureString objet.
using namespace System;
using namespace System::Security;
void main()
{
String^ msg = L" The current length of the SecureString object: {0}\n";
SecureString ^ ss = gcnew SecureString;
Console::WriteLine(L"1) Instantiate the SecureString object:");
Console::WriteLine(msg, ss->Length );
Console::WriteLine(L"2) Append 'a' to the value:");
ss->AppendChar('a');
Console::WriteLine(msg, ss->Length );
Console::WriteLine(L"3) Append 'X' to the value:");
ss->AppendChar('X');
Console::WriteLine(msg, ss->Length);
Console::WriteLine(L"4) Append 'c' to the value:");
ss->AppendChar('c');
Console::WriteLine(msg, ss->Length);
Console::WriteLine(L"5) Insert 'd' at the end of the value:");
ss->InsertAt(ss->Length, 'd');
Console::WriteLine(msg, ss->Length);
Console::WriteLine(L"6) Remove the last character ('d') from the value:");
ss->RemoveAt(3);
Console::WriteLine(msg, ss->Length);
Console::WriteLine(L"7) Set the second character ('X') of the value to 'b':" );
ss->SetAt(1, 'b');
Console::WriteLine(msg, ss->Length );
Console::WriteLine(L"8) Delete the value of the SecureString object:");
ss->Clear();
Console::WriteLine(msg, ss->Length);
delete ss;
}
/*
This code example produces the following results:
This example demonstrates the effect of the AppendChar, InsertAt,
RemoveAt, SetAt, and Clear methods on the value of a SecureString
object. This example simulates the value of the object because the
actual value is encrypted.
1) The initial value of the SecureString object:
SecureString = ""
Length = 0
2) AppendChar: Append 'a' to the value:
SecureString = "a"
Length = 1
3) AppendChar: Append 'X' to the value:
SecureString = "aX"
Length = 2
4) AppendChar: Append 'c' to the value:
SecureString = "aXc"
Length = 3
5) InsertAt: Insert 'd' at the end of the value (equivalent
to AppendChar):
SecureString = "aXcd"
Length = 4
6) RemoveAt: Remove the last character ('d') from the value:
SecureString = "aXc"
Length = 3
7) SetAt: Set the second character ('X') of the value to 'b':
SecureString = "abc"
Length = 3
8) Clear: Delete the value of the SecureString object:
SecureString = ""
Length = 0
*/
using System;
using System.Security;
class Example
{
public static void Main()
{
string msg = "The curent length of the SecureString object: {0}\n";
Console.WriteLine("1) Instantiate the SecureString object.");
SecureString ss = new SecureString();
Console.WriteLine(msg, ss.Length);
Console.WriteLine("2) Append 'a' to the value.");
ss.AppendChar('a');
Console.WriteLine(msg, ss.Length);
Console.WriteLine("3) Append 'X' to the value.");
ss.AppendChar('X');
Console.WriteLine(msg, ss.Length);
Console.WriteLine("4) Append 'c' to the value.");
ss.AppendChar('c');
Console.WriteLine(msg, ss.Length);
Console.WriteLine("5) Insert 'd' at the end of the value.");
ss.InsertAt(ss.Length, 'd');
Console.WriteLine(msg, ss.Length);
Console.WriteLine("6) Remove the last character ('d') from the value.");
ss.RemoveAt(3);
Console.WriteLine(msg, ss.Length);
Console.WriteLine("7) Set the second character of the value to 'b'.");
ss.SetAt(1, 'b');
Console.WriteLine(msg, ss.Length);
Console.WriteLine("8) Delete the value of the SecureString object:");
ss.Clear();
Console.WriteLine(msg, ss.Length);
ss.Dispose();
}
}
// The example displays the following output:
// 1) Instantiate the SecureString object.
// The curent length of the SecureString object: 0
//
// 2) Append 'a' to the value.
// The curent length of the SecureString object: 1
//
// 3) Append 'X' to the value.
// The curent length of the SecureString object: 2
//
// 4) Append 'c' to the value.
// The curent length of the SecureString object: 3
//
// 5) Insert 'd' at the end of the value.
// The curent length of the SecureString object: 4
//
// 6) Remove the last character ('d') from the value.
// The curent length of the SecureString object: 3
//
// 7) Set the second character of the value to 'b'.
// The curent length of the SecureString object: 3
//
// 8) Delete the value of the SecureString object:
// The curent length of the SecureString object: 0
Imports System.Security
Module Example
Public Sub Main()
Dim msg As String = "The curent length of the SecureString object: {0}" + vbCrLf
Console.WriteLine("1) Instantiate the SecureString object.")
Dim ss As New SecureString()
Console.WriteLine(msg, ss.Length)
Console.WriteLine("2) Append 'a' to the value.")
ss.AppendChar("a"c)
Console.WriteLine(msg, ss.Length)
Console.WriteLine("3) Append 'X' to the value.")
ss.AppendChar("X"c)
Console.WriteLine(msg, ss.Length)
Console.WriteLine("4) Append 'c' to the value.")
ss.AppendChar("c"c)
Console.WriteLine(msg, ss.Length)
Console.WriteLine("5) Insert 'd' at the end of the value.")
ss.InsertAt(ss.Length, "d"c)
Console.WriteLine(msg, ss.Length)
Console.WriteLine("6) Remove the last character ('d') from the value.")
ss.RemoveAt(3)
Console.WriteLine(msg, ss.Length)
Console.WriteLine("7) Set the second character of the value to 'b'.")
ss.SetAt(1, "b"c)
Console.WriteLine(msg, ss.Length)
Console.WriteLine("8) Delete the value of the SecureString object:")
ss.Clear()
Console.WriteLine(msg, ss.Length)
ss.Dispose()
End Sub
End Module
' The example displays the following output:
' 1) Instantiate the SecureString object.
' The curent length of the SecureString object: 0
'
' 2) Append 'a' to the value.
' The curent length of the SecureString object: 1
'
' 3) Append 'X' to the value.
' The curent length of the SecureString object: 2
'
' 4) Append 'c' to the value.
' The curent length of the SecureString object: 3
'
' 5) Insert 'd' at the end of the value.
' The curent length of the SecureString object: 4
'
' 6) Remove the last character ('d') from the value.
' The curent length of the SecureString object: 3
'
' 7) Set the second character of the value to 'b'.
' The curent length of the SecureString object: 3
'
' 8) Delete the value of the SecureString object:
' The curent length of the SecureString object: 0
Remarques
La mémoire de l’ordinateur qui contient la valeur de cette chaîne sécurisée est zéro, puis la longueur de la valeur de cette chaîne sécurisée est définie sur zéro.
S’applique à
Voir aussi
Commentaires
https://aka.ms/ContentUserFeedback.
Bientôt disponible : Tout au long de 2024, nous allons supprimer progressivement GitHub Issues comme mécanisme de commentaires pour le contenu et le remplacer par un nouveau système de commentaires. Pour plus d’informations, consultezEnvoyer et afficher des commentaires pour