SecureString.SetAt(Int32, Char) Method

Definition

Namespace:

System.Security

Assemblies:

netstandard.dll, System.Runtime.InteropServices.dll

Source:

SecureString.cs

Replaces the existing character at the specified index position with another character.

C#

public void SetAt(int index, char c);

Parameters

index

Int32

The index position of an existing character in this secure string.

c

Char

A character that replaces the existing character.

Exceptions

ObjectDisposedException

This secure string has already been disposed.

InvalidOperationException

This secure string is read-only.

ArgumentOutOfRangeException

index is less than zero, or greater than or equal to the length of this secure string.

CryptographicException

An error occurred while protecting or unprotecting the value of this secure string.

Examples

The following example demonstrates how the AppendChar, InsertAt, RemoveAt, SetAt, and Clear methods affect the value of a SecureString object.

C#

using System;
using System.Security;

class SecureStringExample
{
    public static void Main()
    {
       string msg = "The current 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 current length of the SecureString object: 0
//
//       2) Append 'a' to the value.
//       The current length of the SecureString object: 1
//
//       3) Append 'X' to the value.
//       The current length of the SecureString object: 2
//
//       4) Append 'c' to the value.
//       The current length of the SecureString object: 3
//
//       5) Insert 'd' at the end of the value.
//       The current length of the SecureString object: 4
//
//       6) Remove the last character ('d') from the value.
//       The current length of the SecureString object: 3
//
//       7) Set the second character of the value to 'b'.
//       The current length of the SecureString object: 3
//
//       8) Delete the value of the SecureString object:
//       The current length of the SecureString object: 0

Remarks

The index is zero-based; the first character in this instance is at index position zero.

If the implementation uses a protection mechanism, such as encryption, the value of the secure string, if any, is unprotected; c is assigned to the specified index position; then the new value is re-protected.

Applies to