SecureString.SetAt(Int32, Char) Metoda

Reference

Definice

Obor názvů:: System.Security

Sestavení:: System.Runtime.InteropServices.dll

Sestavení:: netstandard.dll

Sestavení:: System.Security.SecureString.dll

Sestavení:: mscorlib.dll

Důležité

Některé informace platí pro předběžně vydaný produkt, který se může zásadně změnit, než ho výrobce nebo autor vydá. Microsoft neposkytuje žádné záruky, výslovné ani předpokládané, týkající se zde uváděných informací.

Nahradí stávající znak na pozici zadaného indexu jiným znakem.

public:
 void SetAt(int index, char c);

public void SetAt (int index, char c);

[System.Runtime.ExceptionServices.HandleProcessCorruptedStateExceptions]
public void SetAt (int index, char c);

member this.SetAt : int * char -> unit

[<System.Runtime.ExceptionServices.HandleProcessCorruptedStateExceptions>]
member this.SetAt : int * char -> unit

Public Sub SetAt (index As Integer, c As Char)

Parametry

index: Int32

Index pozice existujícího znaku v tomto zabezpečeném řetězci.

c: Char

Znak, který nahradí stávající znak.

Atributy: HandleProcessCorruptedStateExceptionsAttribute

Výjimky

ObjectDisposedException

Tento zabezpečený řetězec již byl uvolněn.

InvalidOperationException

Tento zabezpečený řetězec je jen pro čtení.

ArgumentOutOfRangeException

index je menší než nula nebo větší nebo rovna délce tohoto zabezpečeného řetězce.

CryptographicException

Při ochraně nebo odemknutí hodnoty tohoto zabezpečeného řetězce došlo k chybě.

Příklady

Následující příklad ukazuje, jak AppendChar metody, InsertAt , RemoveAt , SetAt a Clear ovlivňují hodnotu SecureString objektu.

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

Poznámky

Index je založený na nule; první znak v této instanci je na pozici nula v indexu.

Pokud implementace používá mechanismus ochrany, jako je například šifrování, je hodnota zabezpečeného řetězce, pokud existuje, nechráněná; c je přiřazen k zadané pozici indexu; nová hodnota je znovu chráněna.

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