I had always had issue with implementing ICloneable in the .Net Framework on my classes.  Implementing ICloneable requires that you return an Object, but a lot of time you don’t want to return an Object type, you want to return a strongly typed object of type whatever.

Well, thanks to a tip I heard on .NetRocks from Rocky Lhotka, I have coded up an example of how you can a) Implement ICloneable, and b) return a strongly typed object from your Clone method.

Imports System

Public Class BusinessObject
    Implements ICloneable

    Private Function privateClone() As Object Implements ICloneable.Clone
        Dim MyClone As Object = makeClone()
        Return MyClone
    End Function

    Public Function Clone() As BusinessObject
        Dim MyClone As BusinessObject = makeClone()
        Return MyClone
    End Function

    Private Function makeClone() As BusinessObject
        '*** do the clone here
    End Function

End Class

The trick is to implement ICloneable as a private function.  To be honest I have no idea why this works.  You would think that implementing the Clone method as a private function would mean that you couldn’t access it, but as the code I wrote below shows, it does work.

imports Microsoft.VisualBasic
imports System
imports System.Collections

public module MyModule
    sub Main
        RL()
        dim o as new BusinessObject
        WL("IClone " & o.Clone.IClone)
        WL("StandardClone " & o.Clone.StandardClone)
        dim i as System.ICloneable 
        i = ctype(o, System.ICloneable)
        WL("IClone " & ctype(i.Clone,BusinessObject).IClone)
        WL("StandardClone " & ctype(i.Clone,BusinessObject).StandardClone)
        RL()
    end sub

    #region "Helper methods"

    sub WL(text as object)
        Console.WriteLine(text)
    end sub

    sub WL(text as object, paramarray args as object())
        Console.WriteLine(text.ToString(), args)
    end sub
        
    sub RL()
        Console.ReadLine()
    end sub
    
    sub Break() 
        System.Diagnostics.Debugger.Break()
    end sub

    #end region

end module


public Class BusinessObject
    Implements System.ICloneable
    public IClone as string = ""
    public StandardClone as string = ""

    Private Function privateClone() As Object Implements ICloneable.Clone
        Dim MyClone As Object = makeClone()
        ctype(MyClone,BusinessObject).IClone = "true"
        Return MyClone
    End Function

    Public Function Clone() As BusinessObject
        Dim MyClone As BusinessObject = makeClone()
        MyClone.StandardClone = "true"
        Return MyClone
    End Function

    Private Function makeClone() As BusinessObject
        '*** do the clone here
        return new BusinessObject
    End Function

End Class

I will have to get to the bottom of this private thing.  But at least this will work and do you want expect it to.

Update: I got some answers from a couple people online.
Alvin Bruney (http://msmvps.com/blogs/Alvin/ ) suggested:

This I knew, but I guess I was wondering why the compiler allows you to do this.  I guess it makes sense that the interface makes that method public, so public it is!   Case closed

Well a little tweaking of the code that does the generation of the formatted code, and it now produces what I want:

        Public Shared Function AddTOQueryString(ByVal URL As String, ByVal Key As String, ByVal Value As String) As String
            Dim RegExp As New System.Text.RegularExpressions.Regex(Key & "=.*?(&|$)")
            Dim Match As System.Text.RegularExpressions.Match = RegExp.Match(URL)
            If Match.Success Then
                Return RegExp.Replace(URL, Key & "=" & Value & Match.Groups(1).ToString)
            ElseIf URL.IndexOf("?") > 0 Then
                Return URL & "&" & Key & "=" & Value
            Else
                Return URL & "?" & Key & "=" & Value
            End If
        End Function

        /// <summary>Gets or sets the RSS version to write.</summary>
        /// <exception cref="InvalidOperationException">Can't change version number after data has been written.</exception>
        public RssVersion Version
        {
            get { return rssVersion; }
            set
            {
                if(wroteStartDocument)
                    throw new InvalidOperationException("Can't change version number after data has been written.");
                else
                    rssVersion = value;
            }
        }

I am not sure that I like what it does with literal strings.  I will probably want to change that.

I am also now convinced that it will not due for formatting Javascript.  J# just doesn’t share enough similar attributes.  This tool also doesn’t support XML (or HTML), which would be a nice thing too.

This converter looks pretty sweet.  You can include your regions and it will let you keep them collapsed and then expand via javascript, excellent.

I could also just wire up the implementation I already have to deal with HTML and Javascript.

We will see… for now this will do.

I was just about to make a post talking about the switch over to dasBlog.  I was going to talk about what I liked and didn’t like and whatever, but mostly I was going to talk about the work I have been putting in on writing code that will filter out code and format it nicely.

I wrote and tested an HttpModule which loads a Reponse Filter that parses the Html looking for <code> tags and formats the code inside those nicely.

So I go to write my first post, and I am looking for a hyperlink button in the texteditor, but instead I see this icon that look like a C# file.  “No, I did not just waste all that time” I thought. 

public bool IsTimeWasted(String name){
    return true;
}

Public Function IsWasted(ByVal time As TimeSpent) As Boolean
  If time IsNot Nothing Then
    Return True
  Else
    Return False
  End If
End Function

var s;
s = ‘asdf’;
document.getElementById(“asdf”); /* comment */

SELECT * FROM
ThingsToDo
WHERE
WastedTime <> 1
AND
Task = ‘Writing HttpFilter’

0 rows returned

So you can see I basically wasted my time doing all that.

This tool doesn’t provide an HTML code type, and I used J# in place of Javascript, but it works ok I guess.

The on thing it is really lacking is that it doesn’t maintain indents!?!?  I manually restored the indents above, otherwise my vb code would look like this:

Public Function IsWasted(ByVal time As TimeSpent) As Boolean
If time IsNot Nothing Then
Return True
Else
Return False
End If
End Function

Which is weird, b/c it looks fine in the preview window… I will have to look into that.