Imports System
Imports System.Data.SqlTypes
Imports Microsoft.SqlServer.Server
Imports System.Text
<Serializable(), SqlUserDefinedTypeAttribute(Format.Native, _
IsByteOrdered:=True, _
ValidationMethodName:="ValidatePointF")> _
Public Structure PointF
Implements INullable
Private is_Null As Boolean
Private _x As Single
Private _y As Single
Public ReadOnly Property IsNull() As Boolean _
Implements INullable.IsNull
Get
Return (is_Null)
End Get
End Property
Public Shared ReadOnly Property Null() As PointF
Get
Dim pt As New PointF
pt.is_Null = True
Return (pt)
End Get
End Property
' Use StringBuilder to provide string representation of UDT.
Public Overrides Function ToString() As String
' Since InvokeIfReceiverIsNull defaults to 'true'
' this test is unneccesary if Point is only being called
' from SQL.
If Me.IsNull Then
Return "NULL"
Else
Dim builder As StringBuilder = New StringBuilder
builder.Append(_x)
builder.Append(",")
builder.Append(_y)
Return builder.ToString
End If
End Function
<SqlMethod(OnNullCall:=False)> _
Public Shared Function Parse(ByVal s As SqlString) As PointF
' With OnNullCall=False, this check is unnecessary if
' Point only being called from SQL.
If s.IsNull Then
Return Null
End If
' Parse input string here to separate out points.
Dim pt As New PointF()
Dim xy() As String = s.Value.Split(",".ToCharArray())
pt.X = Single.Parse(xy(0))
pt.Y = Single.Parse(xy(1))
' Call ValidatePoint to enforce validation
' for string conversions.
If Not pt.ValidatePointF() Then
Throw New ArgumentException("Invalid XY coordinate values.")
End If
Return pt
End Function
' X and Y coordinates are exposed as properties.
Public Property X() As Single
Get
Return (Me._x)
End Get
Set(ByVal Value As Single)
Dim temp As Single = _x
_x = Value
If Not ValidatePointF() Then
_x = temp
Throw New ArgumentException("Invalid X coordinate value.")
End If
End Set
End Property
Public Property Y() As Single
Get
Return (Me._y)
End Get
Set(ByVal Value As Single)
Dim temp As Single = _y
_y = Value
If Not ValidatePointF() Then
_y = temp
Throw New ArgumentException("Invalid Y coordinate value.")
End If
End Set
End Property
' XをDecimal型で返す
Public ReadOnly Property XDecimal() As Decimal
Get
Return CType(Me._x, Decimal)
End Get
End Property
' YをDecimal型で返す
Public ReadOnly Property YDecimal() As Decimal
Get
Return CType(Me._y, Decimal)
End Get
End Property
' Validation method to enforce valid X and Y values.
Private Function ValidatePointF() As Boolean
' Allow only zero or positive integers for X and Y coordinates.
If (_x >= 0) And (_y >= 0) Then
Return True
Else
Return False
End If
End Function
' Distance from 0 to Point method.
<SqlMethod(OnNullCall:=False)> _
Public Function Distance() As Double
Return DistanceFromXY(0, 0)
End Function
' Distance from Point to the specified point method.
<SqlMethod(OnNullCall:=False)> _
Public Function DistanceFrom(ByVal pFrom As Point) As Double
Return DistanceFromXY(pFrom.X, pFrom.Y)
End Function
' Distance from Point to the specified x and y values method.
<SqlMethod(OnNullCall:=False)> _
Public Function DistanceFromXY(ByVal ix As Single, ByVal iy As Single) _
As Double
Return Math.Sqrt(Math.Pow(ix - _x, 2.0) + Math.Pow(iy - _y, 2.0))
End Function
End Structure
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