'''<summary>diese klasse ersetzt null values durch den parameter 'NullReplaceValue' von der parameter tabelle</summary>
'''Achtung! dies funktioniert nicht mit allen daten typen! zur zeit ist der replace wert = -5648945
'''dies heisst, dass sämtliche unsigned, binary, Datums und boolean-Datentypen nicht unterstützt werden.
'''gut nachdenken befor neue datentypen hier eingetragen werden!
Public Class NullHandler
	Public Shared _nullReplacerInt As Integer
	Public Shared _nullReplacerStr As String


	Shared Sub New()
		_nullReplacerInt = Integer.Parse(Config.GetParameterValue("NullReplaceValue"))
		_nullReplacerStr = Config.GetParameterValue("NullReplaceValue")
	End Sub

	Public Shared Function CToInt16(ByVal o As Object) As Int16
		If o Is System.DBNull.Value Then
			Return CShort(_nullReplacerInt)
		Else
			If TypeOf o Is Int16 Then
				Return CShort(o)
			End If
		End If
	End Function

	Public Shared Function CToInt32(ByVal o As Object) As Int32
		If o Is System.DBNull.Value Then
			Return _nullReplacerInt
		Else
			If TypeOf o Is Int32 Then
				Return CInt(o)
			End If
		End If
	End Function

	Public Shared Function CToInt64(ByVal o As Object) As Int64
		If o Is System.DBNull.Value Then
			Return CLng(_nullReplacerInt)
		Else
			If TypeOf o Is Int64 Then
				Return CLng(o)
			End If
		End If
	End Function

	Public Shared Function CToSingle(ByVal o As Object) As Single
		If o Is System.DBNull.Value Then
			Return CSng(_nullReplacerInt)
		Else
			If TypeOf o Is Single Then
				Return CSng(o)
			End If
		End If
	End Function

	Public Shared Function CToDouble(ByVal o As Object) As Double
		If o Is System.DBNull.Value Then
			Return CDbl(_nullReplacerInt)
		Else
			If TypeOf o Is Double Then
				Return CDbl(o)
			End If
		End If
	End Function

	Public Shared Function CToDecimal(ByVal o As Object) As Decimal
		If o Is System.DBNull.Value Then
			Return CDec(_nullReplacerInt)
		Else
			If TypeOf o Is Decimal Then
				Return CDec(o)
			End If
		End If
	End Function

	Public Shared Function CToString(ByVal o As Object) As String
		If o Is System.DBNull.Value Then
			Return _nullReplacerStr
		Else
			If TypeOf o Is String Then
				Return CStr(o)
			End If
		End If
	End Function

	'''<summary>spezialfall wird auf DateTime.MinValue gesetzt</summary>
	'''<param name="o"></param>

	Public Shared Function CToDateTime(ByVal o As Object) As DateTime
		If o Is System.DBNull.Value Then
			Return DateTime.MinValue
		Else
			If TypeOf o Is DateTime Then
				Return CDate(o)
			End If
		End If
	End Function

End Class