COM Data Types

The following table shows data types used in COM and their corresponding .NET Framework built-in value types or classes. Any type not explicitly identified in this table is converted to an Int32 system type. For corresponding types in Visual Basic 2005, C#, and C++, see the Introduction to the .NET Framework Class Library.

COM value type	COM reference type	System type
bool	bool *	System.Int32
char, small	char *, small *	System.SByte
short	short *	System.Int16
long, int	long *, int *	System.Int32
Hyper	hyper *	System.Int64
unsigned char, byte	unsigned char *, byte *	System.Byte
wchar_t, unsigned short	wchar_t *, unsigned short *	System.UInt16
unsigned long, unsigned int	unsigned long *, unsigned int *	System.UInt32
unsigned hyper	unsigned hyper *	System.UInt64
float	float *	System.Single
double	double *	System.Double
VARIANT_BOOL	VARIANT_BOOL *	System.Boolean
void *	void **	System.IntPtr
HRESULT	HRESULT *	System.Int16 or System.IntPtr
SCODE	SCODE *	System.Int32
BSTR	BSTR *	System.String
LPSTR or [string, …] char *	LPSTR *	System.String
LPWSTR or [string, …] wchar_t *	LPWSTR *	System.String
VARIANT	VARIANT *	System.Object
DECIMAL	DECIMAL *	System.Decimal
DATE	DATE *	System.DateTime
GUID	GUID *	System.Guid
CURRENCY	CURRENCY *	System.Decimal
IUnknown *	IUnknown **	System.Object
IDispatch *	IDispatch **	System.Object
SAFEARRAY(type)	SAFEARRAY(type) *	type[]

The following table lists COM value and reference types that convert to corresponding element types. For example, a COM coclass automatically maps to a managed class with the same name.

COM value type	COM reference type	Element type
Typedef BaseType MyType	ByRef BaseType	BaseType
MyStruct	ByRef VALUETYPE<MyStruct>	valuetype<MyStruct>
MyEnum	ByRef VALUETYPE<MyEnum>	valuetype<MyEnum>
MyInterface *	ByRef CLASS <MyInterface>	Class <MyInterface>
MyCoClass	ByRef CLASS <_Class>	Class <_Class>

See Also

Concepts

Customizing COM Callable Wrappers

Customizing Runtime Callable Wrappers

Other Resources

Marshaling Data with COM Interop