Article
11/18/2011

UnmanagedType Enumeration

Microsoft Silverlight will reach end of support after October 2021. Learn more.

This API supports the .NET Framework infrastructure and is not intended to be used directly from your code.

Identifies how to marshal parameters or fields to unmanaged code.

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

Syntax

'Declaration
<ComVisibleAttribute(True)> _
Public Enumeration UnmanagedType

[ComVisibleAttribute(true)]
public enum UnmanagedType

Members

	Member name	Description
	Bool	A 4-byte Boolean value (true != 0, false = 0). This is the Win32 BOOL type.
	I1	A 1-byte signed integer. You can use this member to transform a Boolean value into a 1-byte, C-style bool (true = 1, false = 0).
	U1	A 1-byte unsigned integer.
	I2	A 2-byte signed integer.
	U2	A 2-byte unsigned integer.
	I4	A 4-byte signed integer.
	U4	A 4-byte unsigned integer.
	I8	An 8-byte signed integer.
	U8	An 8-byte unsigned integer.
	R4	A 4-byte floating point number.
	R8	An 8-byte floating point number.
	Currency	Used on a System.Decimal to marshal the decimal value as a COM currency type instead of as a Decimal.
	LPStr	A single byte, null-terminated ANSI character string. You can use this member on the System.String or System.Text.StringBuilder data types
	LPWStr	A 2-byte, null-terminated Unicode character string. Note that you cannot use the LPWStr value with an unmanaged string unless the string was created using the unmanaged CoTaskMemAlloc function.
	LPTStr	A platform-dependent character string: ANSI on Windows 98 and Unicode on Windows NT and Windows XP. This value is only supported for platform invoke, and not COM interop, because exporting a string of type LPTStr is not supported.
	ByValTStr	Used for in-line, fixed-length character arrays that appear within a structure. The character type used with ByValTStr is determined by the System.Runtime.InteropServices.CharSet argument of the System.Runtime.InteropServices.StructLayoutAttribute applied to the containing structure. Always use the MarshalAsAttribute.SizeConst field to indicate the size of the array. .NET Framework ByValTStr types behave like C-style, fixed-size strings inside a structure (for example, char s[5]). The behavior in managed code differs from the Microsoft Visual Basic 6.0 behavior, which is not null terminated (for example, MyString As String * 5).
	IUnknown	A COM IUnknown pointer. You can use this member on the Object data type.
	Struct	A VARIANT, which is used to marshal managed formatted classes and value types.
	ByValArray	When MarshalAsAttribute.Value is set to ByValArray, the SizeConst must be set to indicate the number of elements in the array. The ArraySubType field can optionally contain the UnmanagedType of the array elements when it is necessary to differentiate among string types. You can only use this UnmanagedType on an array that appear as fields in a structure.
	SysInt	A platform-dependent, signed integer. 4-bytes on 32 bit Windows, 8-bytes on 64 bit Windows.
	SysUInt	A platform-dependent, unsigned integer. 4-bytes on 32 bit Windows, 8-bytes on 64 bit Windows.
	FunctionPtr	An integer that can be used as a C-style function pointer. You can use this member on a Delegate data type or a type that inherits from a Delegate.
	AsAny	A dynamic type that determines the type of an object at run time and marshals the object as that type. Valid for platform invoke methods only.
	LPArray	A pointer to the first element of a C-style array. When marshaling from managed to unmanaged, the length of the array is determined by the length of the managed array. When marshaling from unmanaged to managed, the length of the array is determined from the MarshalAsAttribute.SizeConst and the MarshalAsAttribute.SizeParamIndex fields, optionally followed by the unmanaged type of the elements within the array when it is necessary to differentiate among string types.
	LPStruct	A pointer to a C-style structure that you use to marshal managed formatted classes. Valid for platform invoke methods only.
	Error	This native type associated with an I4 or a U4 causes the parameter to be exported as a HRESULT in the exported type library.
	BStr	A Unicode character string that is a length-prefixed double byte. You can use this member, which is the default string in COM, on the String data type.
	IDispatch	A COM IDispatch pointer (Object in Microsoft Visual Basic 6.0).
	Interface	A COM interface pointer. The Guid of the interface is obtained from the class metadata. Use this member to specify the exact interface type or the default interface type if you apply it to a class. This member produces UnmanagedType.IUnknown behavior when you apply it to the Object data type.
	SafeArray	A SafeArray is a self-describing array that carries the type, rank, and bounds of the associated array data.
	VBByRefStr	Allows Visual Basic 2005 to change a string in unmanaged code, and have the results reflected in managed code. This value is only supported for platform invoke.
	AnsiBStr	An ANSI character string that is a length prefixed, single byte. You can use this member on the String data type.
	TBStr	A length-prefixed, platform-dependent char string. ANSI on Windows 98, Unicode on Windows NT. You rarely use this BSTR-like member.
	VariantBool	A 2-byte, OLE-defined VARIANT_BOOL type (true = -1, false = 0).
	CustomMarshaler	Specifies the custom marshaler class when used with MarshalAsAttribute.MarshalType or MarshalAsAttribute.MarshalTypeRef. The MarshalAsAttribute.MarshalCookie field can be used to pass additional information to the custom marshaler. You can use this member on any reference type.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.