次の方法で共有


TemplateParameter.vb

Imports System
Imports System.Data

Namespace DotNetDataProviderTemplate
  Public Class TemplateParameter
    Implements IDataParameter

    Dim m_dbType As DbType = DbType.Object
    Dim m_direction As ParameterDirection = ParameterDirection.Input
    Dim m_fNullable As Boolean = False
    Dim m_sParamName As String
    Dim m_sSourceColumn As String
    Dim m_sourceVersion As DataRowVersion = DataRowVersion.Current
    Dim m_value As Object

    Public Sub New()
      MyBase.New
    End Sub

    Public Sub New(ByVal parameterName As String, ByVal type As DbType)
      MyBase.New

      m_sParamName  = parameterName
      m_dbType  = type
    End Sub

    Public Sub New(ByVal parameterName As String, ByVal value As Object)
      MyBase.New

      m_sParamName   = parameterName
      Me.Value   = value 
      ' Setting the value also infers the type.
    End Sub

    Public Sub New(ByVal parameterName As String, ByVal type As DbType, ByVal sourceColumn As String)
      MyBase.New

      m_sParamName  = parameterName
      m_dbType  = dbType
      m_sSourceColumn = sourceColumn
    End Sub

    Public Property DbType As DbType Implements IDataParameter.DbType
      Get
        Return m_dbType
      End Get
      Set
        m_dbType = value
      End Set
    End Property

    Public Property Direction As ParameterDirection Implements IDataParameter.Direction
      Get
        Return m_direction
      End Get
      Set
        m_direction = value
      End Set
    End Property

    Public ReadOnly Property IsNullable As Boolean Implements IDataParameter.IsNullable
      Get
        Return m_fNullable
      End Get
    End Property

    Public Property ParameterName As String  Implements IDataParameter.ParameterName
      Get
        Return m_sParamName
      End Get
      Set
        m_sParamName = value
      End Set
    End Property

    Public Property SourceColumn As String  Implements IDataParameter.SourceColumn 
      Get
        Return m_sSourceColumn
      End Get
      Set
        m_sSourceColumn = value
      End Set
    End Property

    Public Property SourceVersion As DataRowVersion  Implements IDataParameter.SourceVersion 
      Get
        Return m_sourceVersion
      End Get
      Set
        m_sourceVersion = value
      End Set
    End Property

    Public Property Value As Object  Implements IDataParameter.Value 
      Get
        Return m_value
      End Get
      Set
        m_value    = value
        m_dbType  = _inferType(value)
      End Set
    End Property

    Private Function _inferType(value As Object) As DbType
      Select Case (Type.GetTypeCode(value.GetType()))
        Case TypeCode.Empty
          Throw New SystemException("Invalid data type")

        Case TypeCode.Object
          Return DbType.Object

        Case TypeCode.DBNull
        Case TypeCode.Char
        Case TypeCode.SByte
        Case TypeCode.UInt16
        Case TypeCode.UInt32
        Case TypeCode.UInt64
          ' Throw a SystemException for unsupported data types.
          Throw New SystemException("Invalid data type")

        Case TypeCode.Boolean
          Return DbType.Boolean

        Case TypeCode.Byte
          Return DbType.Byte

        Case TypeCode.Int16
          Return DbType.Int16

        Case TypeCode.Int32
          Return DbType.Int32

        Case TypeCode.Int64
          Return DbType.Int64

        Case TypeCode.Single
          Return DbType.Single

        Case TypeCode.Double
          Return DbType.Double

        Case TypeCode.Decimal
          Return DbType.Decimal

        Case TypeCode.DateTime
          Return DbType.DateTime

        Case TypeCode.String
          Return DbType.String

        Case Else
          Throw New SystemException("Value is of unknown data type")
      End Select
    End Function
  End Class
End NameSpace