Monthly Archives: August 2009

Sketchflow – “Duplicate” Bug





The Problem

At the moment I’m trialling Sketchflow for Expression Blend.  There’s an annoying bug that happens when you use the “Duplicate” action on a node:


If you use this action, sooner or later you’ll end up with this error:

‘InitializeComponent’ is not a member of ‘xxxxxxxxxx.xxxxxxxxxxxxxx’

This can be very frustrating if you are trying to advocate Sketchflow as a prototyping tool for non wpf savvy analysts.

The Workaround

The simplest workaround is to delete the code-behind file.  To do this, go to the project pane and choose “Delete”.



At first I tried hard to ensure that the xaml filenames and classnames were correct.  This just causes a cascading comedy of errors.

Upgrading Sketchflow prototype projects to real code is a pipe-dream at the moment.

If you know of a better way of handling this situation (and fixing the errors) more quickly, feel free to comment.  I just want get on with the prototyping.

Serialize and Deserialize objects as Xml using generic types in VB.Net



In his blog post Serialize and deserialize objects as xml using generic types in C# 2.0 , Paul Whitaker creates some ubiquitous functions for doing Xml Serialization with generics.


To serialize:

Dim lsXml As String = GenericXmlSerializer.SerializeObject(of MyObjectType)(myObject)


To deserialize:

Dim myObject As MyObjectType = GenericXmlSerializer.DeserializeObject(of MyObjectType)(lsXml)


Here’s the code

Imports System.Collections.Generic
Imports System.Text
Imports System.Xml
Imports System.IO
Imports System.Xml.Serialization

Class GenericXmlSerializer
    ''' <summary>
    ''' To convert a Byte Array of Unicode values (UTF-8 encoded) to a complete String.
    ''' </summary>
    ''' <param name="characters">Unicode Byte Array to be converted to String</param>
    ''' <returns>String converted from Unicode Byte Array</returns>
    Public Shared Function UTF8ByteArrayToString(ByVal characters As Byte()) As String

        Dim encoding As New UTF8Encoding
        Dim constructedString As String = encoding.GetString(characters)
        Return constructedString

    End Function

    ''' <summary>
    ''' Converts the String to UTF8 Byte array and is used in De serialization
    ''' </summary>
    ''' <param name="pXmlString"></param>
    ''' <returns></returns>
    Public Shared Function StringToUTF8ByteArray(ByVal pXmlString As String) As Byte()

        Dim encoding As New UTF8Encoding()
        Dim byteArray As Byte() = encoding.GetBytes(pXmlString)
        Return byteArray
    End Function

    ''' <summary>
    ''' Serialize an object into an XML string
    ''' </summary>
    ''' <typeparam name="T"></typeparam>
    ''' <param name="obj"></param>
    ''' <returns></returns>
    Public Shared Function SerializeObject(Of T)(ByVal obj As T) As String

            Dim xmlString As String = Nothing

            Dim memoryStream As New MemoryStream()
            Dim xs As New XmlSerializer(GetType(T))
            Dim xmlTextWriter As New XmlTextWriter(memoryStream, Encoding.UTF8)
            xs.Serialize(xmlTextWriter, obj)
            memoryStream = CType(xmlTextWriter.BaseStream, MemoryStream)
            xmlString = UTF8ByteArrayToString(memoryStream.ToArray())

            Return xmlString

            Return String.Empty
        End Try
    End Function

    ''' <summary>
    ''' Reconstruct an object from an XML string
    ''' </summary>
    ''' <param name="xml"></param>
    ''' <returns></returns>
    Public Shared Function DeserializeObject(Of T)(ByVal xml As String) As T

        Dim xs As New XmlSerializer(GetType(T))
        Dim memoryStream As New MemoryStream(StringToUTF8ByteArray(xml))
        Dim xmlTextWriter As New XmlTextWriter(memoryStream, Encoding.UTF8)

        Dim theObject As T = CType(xs.Deserialize(memoryStream), T)
        Return theObject

    End Function

End Class


Rather than be original, I converted most of his code verbatim and have found the functions useful. 

I offer them to you warranty free, unadorned and hopefully useful.



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Flick Scrolling in Winforms




In the article A Simple Scroll Controller for Winforms I mentioned that I was working on a FlickScrolling framework for Winforms.

I finished a version of this code a couple of months ago and it seems to work well.  

The code never went into production because I think that Windows 7 will provide this functionality automatically for winforms applications. 

Nevertheless, some people have showed an interest in what I came up with, so I’m posting it here for your edification.  I hope someone finds it useful.


To use, simply instantiate the “ApplicationFlickScrolling” class, passing in the datatypes of the container controls you wish to scroll.

For example:

Private Shared moApplicationFlick As New ApplicationFlickScrolling(GetType(Panel))

To switch it on and off, used the “Enabled” property:

moApplicationFlick.Enabled = True

That’s it!


The Implementation


The code consists of 3 classes:

  • ApplicationFlickScrolling to act as the master controller class
  • ApplicationMouseEvents class for detecting mouse events
  • FlickDetector for detecting simple gestures
  • ScrollController for performing elastic-style easing of scrolling


If I’d have continued developing this I would have modified ScrollController to use “proper” easing functions. 


Note: The usual disclaimers apply for this code, which has been given freely to help others learn and is not intended for usage in your business application or for running a nuclear facility.
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