UnmanagedType UnmanagedType UnmanagedType Enum

Definition

Identifies how to marshal parameters or fields to unmanaged code.

public enum class UnmanagedType
[System.Runtime.InteropServices.ComVisible(true)]
public enum UnmanagedType
Public Enum UnmanagedType
Inheritance
UnmanagedTypeUnmanagedTypeUnmanagedType
Attributes

Fields

AnsiBStr AnsiBStr AnsiBStr 35

An ANSI character string that is a length-prefixed single byte. You can use this member on the String data type.

AsAny AsAny AsAny 40

A dynamic type that determines the type of an object at run time and marshals the object as that type. This member is valid for platform invoke methods only.

Bool Bool Bool 2

A 4-byte Boolean value (true != 0, false = 0). This is the Win32 BOOL type.

BStr BStr BStr 19

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.

ByValArray ByValArray ByValArray 30

When the Value property is set to ByValArray, the SizeConst field 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 use this UnmanagedType only on an array that whose elements appear as fields in a structure.

ByValTStr ByValTStr ByValTStr 23

Used for in-line, fixed-length character arrays that appear within a structure. The character type used with ByValTStr is determined by the CharSet argument of the StructLayoutAttribute attribute applied to the containing structure. Always use the SizeConst field to indicate the size of the array.

Currency Currency Currency 15

A currency type. Used on a Decimal to marshal the decimal value as a COM currency type instead of as a Decimal.

CustomMarshaler CustomMarshaler CustomMarshaler 44

Specifies the custom marshaler class when used with the MarshalType or MarshalTypeRef field. The MarshalCookie field can be used to pass additional information to the custom marshaler. You can use this member on any reference type. This member is valid for parameters and return values only. It cannot be used on fields.

Error Error Error 45

A native type that is associated with an I4 or an U4 and that causes the parameter to be exported as an HRESULT in the exported type library.

FunctionPtr FunctionPtr FunctionPtr 38

An integer that can be used as a C-style function pointer. You can use this member on a Delegate data type or on a type that inherits from a Delegate.

HString HString HString 47

A Windows Runtime string. You can use this member on the String data type.

I1 I1 I1 3

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).

I2 I2 I2 5

A 2-byte signed integer.

I4 I4 I4 7

A 4-byte signed integer.

I8 I8 I8 9

An 8-byte signed integer.

IDispatch IDispatch IDispatch 26

A COM IDispatch pointer (Object in Microsoft Visual Basic 6.0).

IInspectable IInspectable IInspectable 46

A Windows Runtime interface pointer. You can use this member on the Object data type.

Interface Interface Interface 28

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 the same behavior as IUnknown when you apply it to the Object data type.

IUnknown IUnknown IUnknown 25

A COM IUnknown pointer. You can use this member on the Object data type.

LPArray LPArray LPArray 42

A pointer to the first element of a C-style array. When marshaling from managed to unmanaged code, the length of the array is determined by the length of the managed array. When marshaling from unmanaged to managed code, the length of the array is determined from the SizeConst and SizeParamIndex fields, optionally followed by the unmanaged type of the elements within the array when it is necessary to differentiate among string types.

LPStr LPStr LPStr 20

A single byte, null-terminated ANSI character string. You can use this member on the String and StringBuilder data types.

LPStruct LPStruct LPStruct 43

A pointer to a C-style structure that you use to marshal managed formatted classes. This member is valid for platform invoke methods only.

LPTStr LPTStr LPTStr 22

A platform-dependent character string: ANSI on Windows 98, and Unicode on Windows NT and Windows XP. This value is supported only for platform invoke and not for COM interop, because exporting a string of type LPTStr is not supported.

LPUTF8Str LPUTF8Str LPUTF8Str 48

A pointer to a UTF-8 encoded string.

LPWStr LPWStr LPWStr 21

A 2-byte, null-terminated Unicode character string.

R4 R4 R4 11

A 4-byte floating-point number.

R8 R8 R8 12

An 8-byte floating-point number.

SafeArray SafeArray SafeArray 29

A SafeArray, which is a self-describing array that carries the type, rank, and bounds of the associated array data. You can use this member with the SafeArraySubType field to override the default element type.

Struct Struct Struct 27

A VARIANT, which is used to marshal managed formatted classes and value types.

SysInt SysInt SysInt 31

A platform-dependent, signed integer: 4 bytes on 32-bit Windows, 8 bytes on 64-bit Windows.

SysUInt SysUInt SysUInt 32

A platform-dependent, unsigned integer: 4 bytes on 32-bit Windows, 8 bytes on 64-bit Windows.

TBStr TBStr TBStr 36

A length-prefixed, platform-dependent char string: ANSI on Windows 98, Unicode on Windows NT. You rarely use this BSTR-like member.

U1 U1 U1 4

A 1-byte unsigned integer.

U2 U2 U2 6

A 2-byte unsigned integer.

U4 U4 U4 8

A 4-byte unsigned integer.

U8 U8 U8 10

An 8-byte unsigned integer.

VariantBool VariantBool VariantBool 37

A 2-byte, OLE-defined VARIANT_BOOL type (true = -1, false = 0).

VBByRefStr VBByRefStr VBByRefStr 34

A value that enables Visual Basic to change a string in unmanaged code and have the results reflected in managed code. This value is only supported for platform invoke.

Examples

The following code fragment demonstrates how to declare, in managed source code, an unmanaged interface implemented by a COM component. The System.Runtime.InteropServices.ComImportAttribute attribute prevents the IMyStorage interface from being exported back for use by COM. (COM clients should use the existing COM component directly.) In this example, MarshalAsAttribute specifies serveral UnmanagedType members, which represent the types used by the original COM interface.

using namespace System;
using namespace System::Runtime::InteropServices;

// If you do not have a type library for an interface
// you can redeclare it using ComImportAttribute.
// This is how the interface would look in an idl file.
//[
//object,
//uuid("73EB4AF8-BE9C-4b49-B3A4-24F4FF657B26"),
//dual, helpstring("IMyStorage Interface"),
//pointer_default(unique)
//]
//interface IMyStorage : IDispatch
//{
// [id(1)]
// HRESULT GetItem([in] BSTR bstrName, [out, retval] IDispatch ** ppItem);
// [id(2)]
// HRESULT GetItems([in] BSTR bstrLocation, [out] SAFEARRAY(VARIANT)* pItems);
// [id(3)]
// HRESULT GetItemDescriptions([in] BSTR bstrLocation, [out] SAFEARRAY(VARIANT) ** ppItems);
// [id(4), propget]
// HRESULT get_IsEmpty([out, retval] BOOL * pfEmpty);
//};
// This is the managed declaration.

[ComImport]
[Guid("73EB4AF8-BE9C-4b49-B3A4-24F4FF657B26")]
interface class IMyStorage
{
   [DispId(1)]
   Object^ GetItem( [In,MarshalAs(UnmanagedType::BStr)]String^ bstrName );

   //[return : MarshalAs(UnmanagedType::Interface)]

   [DispId(2)]
   void GetItems( [In,MarshalAs(UnmanagedType::BStr)]String^ bstrLocation, [Out,MarshalAs(UnmanagedType::SafeArray,
   SafeArraySubType=VarEnum::VT_VARIANT)]array<Object^>^Items );

   [DispId(3)]
   void GetItemDescriptions( [In]String^ bstrLocation, [In,Out,MarshalAs(UnmanagedType::SafeArray)]array<Object^>^varDescriptions );

   property bool IsEmpty 
   {
      [DispId(4)]
      [returnvalue:MarshalAs(UnmanagedType::VariantBool)]
      bool get();
   }
};
using System;
using System.Runtime.InteropServices;

namespace MyModule
{
	// If you do not have a type library for an interface
	// you can redeclare it using ComImportAttribute.

	// This is how the interface would look in an idl file.

	//[
	//object,
	//uuid("73EB4AF8-BE9C-4b49-B3A4-24F4FF657B26"),
	//dual,	helpstring("IMyStorage Interface"),
	//pointer_default(unique)
	//]
	//interface IMyStorage : IDispatch
	//{
	//	[id(1)]
	//	HRESULT GetItem([in] BSTR bstrName, [out, retval] IDispatch ** ppItem);
	//	[id(2)]
	//	HRESULT GetItems([in] BSTR bstrLocation, [out] SAFEARRAY(VARIANT)* pItems);
	//	[id(3)]
	//	HRESULT GetItemDescriptions([in] BSTR bstrLocation, [out] SAFEARRAY(VARIANT) ** ppItems);
	//	[id(4), propget]
	//	HRESULT get_IsEmpty([out, retval] BOOL * pfEmpty);
	//};

	// This is the managed declaration.

	[ComImport]
	[Guid("73EB4AF8-BE9C-4b49-B3A4-24F4FF657B26")]
	public interface IMyStorage  
	{
		[DispId(1)]
		[return : MarshalAs( UnmanagedType.Interface )]
		Object GetItem( [In, MarshalAs( UnmanagedType.BStr )] String bstrName );

		[DispId(2)]
		void GetItems( [In, MarshalAs( UnmanagedType.BStr )] String bstrLocation, 
			[Out, MarshalAs( UnmanagedType.SafeArray, 
					  SafeArraySubType = VarEnum.VT_VARIANT )] out Object[] Items );
                
                
		[DispId(3)]
		void GetItemDescriptions( [In] String bstrLocation, 
			[In, Out, MarshalAs( UnmanagedType.SafeArray )] ref Object[] varDescriptions );

		bool IsEmpty 
		{
			[DispId(4)]
			[return : MarshalAs( UnmanagedType.VariantBool )]
			get;
		}
	}
}
Imports System
Imports System.Runtime.InteropServices

Module MyModule
	' If you do not have a type library for an interface
	' you can redeclare it using ComImportAttribute.

	' This is how the interface would look in an idl file.

	'[
	'object,
	'uuid("73EB4AF8-BE9C-4b49-B3A4-24F4FF657B26"),
	'dual,	helpstring("IMyStorage Interface"),
	'pointer_default(unique)
	']
	'interface IMyStorage : IDispatch
	'{
	'	[id(1)]
	'	HRESULT GetItem([in] BSTR bstrName, [out, retval] IDispatch ** ppItem);
	'	[id(2)]
	'	HRESULT GetItems([in] BSTR bstrLocation, [out] SAFEARRAY(VARIANT)* pItems);
	'	[id(3)]
	'	HRESULT GetItemDescriptions([in] BSTR bstrLocation, [out] SAFEARRAY(VARIANT) ** ppItems);
	'	[id(4), propget]
	'	HRESULT get_IsEmpty([out, retval] BOOL * pfEmpty);
	'};

	' This is the managed declaration.

	<ComImport(), Guid("73EB4AF8-BE9C-4b49-B3A4-24F4FF657B26")> _
	Public Interface IMyStorage
		<DispId(1)> _
		Function GetItem(<InAttribute(), MarshalAs(UnmanagedType.BStr)> ByVal bstrName As String) _
		   As <MarshalAs(UnmanagedType.Interface)> Object

		<DispId(2)> _
		Function GetItems(<InAttribute(), MarshalAs(UnmanagedType.BStr)> ByVal bstrLocation As String, _
		   <OutAttribute(), MarshalAs(UnmanagedType.SafeArray, SafeArraySubType := VarEnum.VT_VARIANT)> _
                                      ByVal Items() As Object)

		<DispId(3)> _
		Function GetItemDescriptions(<InAttribute()> ByVal bstrLocation As String, _
		   <InAttribute(), OutAttribute(), _
                      MarshalAs(UnmanagedType.SafeArray)> ByRef varDescriptions() As Object)

		<DispId(4)> _
		ReadOnly Property IsEmpty(<MarshalAs(UnmanagedType.VariantBool)> ByVal bEmpty As Boolean)

	End Interface
End Module

Remarks

Use the UnmanagedType enumeration with the System.Runtime.InteropServices.MarshalAsAttribute attribute to specify how types are marshaled during interoperation with unmanaged code. You can use this enumeration to marshal code using simple value types (I1, I2, I4, I8, R4, R8, U2, U4, and U8), unmanaged types that are unavailable in the .NET Framework, and various miscellaneous types.

For more information, see Interoperating with Unmanaged Code.

Applies to

See Also