Imports System
Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.SqlTypes
Imports Microsoft.SqlServer.Server

Imports System.IO

‘ Declaration of the VarBinaryComp Structure.
‘   We implement the IBinarySerialize interface because of the fact that this
‘   structure uses “UserDefined” serialization
<Serializable()> _
<Microsoft.SqlServer.Server.SqlUserDefinedType(Format.UserDefined, MaxByteSize:=-1)> _
Public Structure VarBinaryComp
    Implements INullable, Microsoft.SqlServer.Server.IBinarySerialize
...
    ‘UDTs must implement the ToString and Parse function to allow conversion
    ‘   to/from strings.  With binary data, these functions provide little practical use.
    Public Overrides Function ToString() As String
        Try
            If m_Bytes Is Nothing Then Return String.Empty
            ‘Convert Compressed Byte Array to String
            Return System.Text.Encoding.Unicode.GetString(m_Bytes.Value)

        Catch ex As Exception
            Throw ex
        End Try
    End Function

    ‘Required property used to determine nullability
    Public ReadOnly Property IsNull() As Boolean Implements INullable.IsNull
        Get
            If m_Bytes Is Nothing Then
                Return True
            End If
            Return False
        End Get
    End Property

    ‘Required function used to return a new, null instance of the UDT.
    Public Shared ReadOnly Property Null() As VarBinaryComp
        Get
            Return New VarBinaryComp(False, Nothing, 0)
        End Get
    End Property

    ‘Example of a custom property (in this case, the uncompressed length of the binary data)
    Public ReadOnly Property UnCompressedLength() As SqlInt32
        Get
            Return m_UnCompressedLength
        End Get
    End Property

    ‘This custom shared function instantiates a new instance of VarBinaryComp,
    ‘   using uncompressed data as input.
    Public Shared Function ParseVarBinaryU(ByVal sUncompressedBytes As SqlBytes) As 
      VarBinaryComp
        Try
            ‘If we are passed in an empty byte array, return a Null instance
            If sUncompressedBytes Is Nothing Then
                Return VarBinaryComp.Null
            End If
            ‘Otherwise, call the overloaded constructor to return a new instance
            Return New VarBinaryComp(False, sUncompressedBytes, 0)
        Catch ex As Exception
            Throw ex
        End Try
    End Function

    ‘This custom shared function instantiates a new instance of VarBinaryComp,
    ‘   using data that is already compressed data as input.
    Public Shared Function ParseVarBinaryC(ByVal sCompressedBytes As SqlBytes, ByVal 
      iUnCompressedLength As SqlInt32) As VarBinaryComp
        Try
            If sCompressedBytes.Value Is Nothing Then
                Return VarBinaryComp.Null
            End If

            Return New VarBinaryComp(True, sCompressedBytes, iUnCompressedLength)
        Catch ex As Exception
            Throw ex
        End Try
    End Function

    ‘UDTs must implement the ToString and Parse function to allow conversion
    ‘   to/from strings.  With binary data, these functions typically are of little value.
    Public Shared Function Parse(ByVal s As SqlString) As VarBinaryComp
        Try
            If s.IsNull Then
                Return VarBinaryComp.Null
            End If