SecureString::Clear Method ()
.NET Framework (current version)
Deletes the value of the current secure string.
Assembly: mscorlib (in mscorlib.dll)
| Exception | Condition |
|---|---|
| ObjectDisposedException | This secure string has already been disposed. |
| InvalidOperationException | This secure string is read-only. |
The computer memory that contains the value of this secure string is zeroed, then the length of the value of this secure string is set to zero.
The following example demonstrates how the AppendChar, InsertAt, RemoveAt, SetAt, and Clear methods affect the value of a SecureString object.
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 */
.NET Framework
Available since 2.0
Available since 2.0
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