Mapping .NET CLR Datatypes with SQL Server 2008 Parameters

The following table maps .NET CLR datatypes with SQL Server parameters.  The full Microsoft article is here.

SQL Server data type	CLR data type (SQL Server)	CLR data type (.NET Framework)
bigint	SqlInt64	Int64, Nullable<Int64>
binary	SqlBytes, SqlBinary	Byte[]
bit	SqlBoolean	Boolean, Nullable<Boolean>
char	None	None
cursor	None	None
date	SqlDateTime	DateTime, Nullable<DateTime>
datetime	SqlDateTime	DateTime, Nullable<DateTime>
datetime2	SqlDateTime	DateTime, Nullable<DateTime>
DATETIMEOFFSET	None	DateTimeOffset, Nullable<DateTimeOffset>
decimal	SqlDecimal	Decimal, Nullable<Decimal>
float	SqlDouble	Double, Nullable<Double>
geography	SqlGeographySqlGeography is defined in Microsoft.SqlServer.Types.dll, which is installed with SQL Server and can be downloaded from the SQL Server 2008 feature pack.	None
geometry	SqlGeometrySqlGeometry is defined in Microsoft.SqlServer.Types.dll, which is installed with SQL Server and can be downloaded from the SQL Server 2008 feature pack.	None
hierarchyid	SqlHierarchyIdSqlHierarchyId is defined in Microsoft.SqlServer.Types.dll, which is installed with SQL Server and can be downloaded from the SQL Server 2008 feature pack.	None
image	None	None
int	SqlInt32	Int32, Nullable<Int32>
money	SqlMoney	Decimal, Nullable<Decimal>
nchar	SqlChars, SqlString	String, Char[]
ntext	None	None
numeric	SqlDecimal	Decimal, Nullable<Decimal>
nvarchar	SqlChars, SqlStringSQLChars is a better match for data transfer and access, and SQLString is a better match for performing String operations.	String, Char[]
nvarchar(1), nchar(1)	SqlChars, SqlString	Char, String, Char[], Nullable<char>
real	SqlSingle	Single, Nullable<Single>
rowversion	None	Byte[]
smallint	SqlInt16	Int16, Nullable<Int16>
smallmoney	SqlMoney	Decimal, Nullable<Decimal>
sql_variant	None	Object
table	None	None
text	None	None
time	TimeSpan	TimeSpan, Nullable<TimeSpan>
timestamp	None	None
tinyint	SqlByte	Byte, Nullable<Byte>
uniqueidentifier	SqlGuid	Guid, Nullable<Guid>
User-defined type(UDT)	None	The same class that is bound to the user-defined type in the same assembly or a dependent assembly.
varbinary	SqlBytes, SqlBinary	Byte[]
varbinary(1), binary(1)	SqlBytes, SqlBinary	byte, Byte[], Nullable<byte>
varchar	None	None
xml	SqlXml	None

Hope this helps.