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Marshal.SecureStringToBSTR Method

Note: This method is new in the .NET Framework version 2.0.

Allocates a BSTR and copies the contents of a managed SecureString object into it.

Namespace: System.Runtime.InteropServices
Assembly: mscorlib (in mscorlib.dll)

public static IntPtr SecureStringToBSTR (
	SecureString s
public static IntPtr SecureStringToBSTR (
	SecureString s
public static function SecureStringToBSTR (
	s : SecureString
) : IntPtr



The managed SecureString object to be copied.

Return Value

The address, in unmanaged memory, where the s parameter was copied to, or 0 if a null SecureString object was supplied.

Exception typeCondition


The s parameter is a null reference (Nothing in Visual Basic).


The current computer is not running Microsoft Windows 2000 Service Pack 3 or later.


There is insufficient memory available.

The SecureStringToBSTR method is useful for custom marshaling or when mixing managed and unmanaged code. Because this method allocates the unmanaged memory required for a string, always free the BSTR when finished by calling the ZeroFreeBSTR method.


This method uses SecurityAction.LinkDemand to prevent it from being called from untrusted code; only the immediate caller is required to have SecurityPermissionAttribute.UnmanagedCode permission. If your code can be called from partially trusted code, do not pass user input to Marshal class methods without validation. For important limitations on using the LinkDemand member, see Demand vs. LinkDemand.

Notes to Callers This method is supported only on computers running Microsoft Windows 2000 Service Pack 3 or later.

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0