Ctype Reloaded

[teguh123]

I am tired of turning one html object into another. One way to do so would be to convert them to ihtmldomnode and then back

So here we go

<Extension()>
    Public Function convertTo(Of Somethingelse)(ByVal node As mshtml.IHTMLDOMNode) As Somethingelse
        Return CType(node, Somethingelse)
    End Function
    <Extension()>
    Public Function toNode(Of something)(ByVal someStuff As something) As mshtml.IHTMLDOMNode
        Return CType(someStuff, mshtml.IHTMLDOMNode)
    End Function
    'Why Can't I do this
    '<Extension()>
    'Public Function CtypeReloaded(Of something, somethingelse)(ByVal someStuff As something) As somethingelse
    '    Return CType(someStuff, somethingelse) 'Error  1   Value of type 'something' cannot be converted to 'somethingelse'.   \\work\c\business\fromwork\currentprojects\program\library\vb.net\internetAccessSupporter.vb    20  22  googlepages2
    '    Return CType("", somethingelse)
    'End Function
 
'I like this one better
    <Extension()>
    Public Function CtypeNode(Of Something, Somethingelse)(ByVal someStuff As Something) As Somethingelse
        Dim node = CType(someStuff, mshtml.IHTMLDOMNode) 'Error 1   Value of type 'something' cannot be converted to 'somethingelse'.   \\work\c\business\fromwork\currentprojects\program\library\vb.net\internetAccessSupporter.vb    20  22  googlepages2
        Return CType(node, Somethingelse)
        'For some reason   Return CType(someStuff, Somethingelse) direct doesn't work
    End Function

[MarMan]

You can define how CType should work with something and somethingelse:

    Public Shared Widening Operator CType(ByVal x As something) As somethingelse

        Dim y As New somethingelse
        ...do conversion here
        Return y

    End Operator

[teguh123]

I need something where I can use template.

[MarMan]

I already gave you a template. I will give you a template with more details. You will have to adapt it to your needs.

Class2:

Public Class Class2

    Private x As Int16 '32767

    Public Property Number() As Int16
        Get
            Return x
        End Get
        Set(ByVal value As Int16)
            x = value
        End Set
    End Property

End Class

Class3:

Public Class Class2

    Private x As Int16 '32767

    Public Property Number() As Int16
        Get
            Return x
        End Get
        Set(ByVal value As Int16)
            x = value
        End Set
    End Property

End Class

Class1 has customized CType functions to convert from Class1 and Class2. These functions are not perfect and can cause exceptions. They are merely for demonstration:

Public Class Class1

    Private x As Int32 '2147483647 

    Public Property Number() As Int32
        Get
            Return x
        End Get
        Set(ByVal value As Int32)
            x = value
        End Set
    End Property

    Public Shared Widening Operator CType(ByVal intNumber As Class2) As Class1
        Dim sngNumber As New Class1
        sngNumber.Number = Convert.ToInt32(intNumber.Number)
        Return sngNumber
    End Operator

    Public Shared Narrowing Operator CType(ByVal dblNumber As Class3) As Class1
        Dim sngNumber As New Class1
        If dblNumber.Number <= 2147483647 And dblNumber.Number >= -2147483648 Then
            sngNumber.Number = Convert.ToInt32(dblNumber.Number)
        End If
        Return sngNumber
    End Operator

End Class

If you wish to text it out then create a form with 3 textboxes and two buttons. You don't have to, but it may help to add 3 labels to the textboxes. Textbox1 is the results of the conversion, the contents of class1. Textbox2 will set the contents of Class2. Ditto with 3. Button1 converts Class2 to Class1. Button2 converts Class3 to Class1.
Form code:

Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim C1 As Class1
        Dim C2 As New Class2

        C2.Number = Int16.Parse(TextBox2.Text)
        C1 = CType(C2, Class1)

        TextBox1.Text = C1.Number.ToString

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

        Dim C1 As Class1
        Dim C3 As New Class3

        C3.Number = Int64.Parse(TextBox3.Text)
        C1 = CType(C3, Class1)

        TextBox1.Text = C1.Number.ToString

    End Sub
End Class