The next Seattle.Net User Group meeting June 10th, 2009

 for more information visit website:

Topic:  Windows Azure.

In this session, David Lemphers, Senior Program Manager for Windows Azure, will provide an overview of Windows Azure, including how-to code demos on building cloud based applications using Windows Azure and Visual Studio.

Speaker: Dave Lemphers
David Lemphers is a Windows Azure program manager based in Redmond. Dave spends most of his time working on features and projects for Windows Azure, but also enjoys blogging and building robots in his spare time.
Originally from Australia, Dave spends his free time making vegemite sandwiches and eating meat pies and lamingtons at Cafe 41!

Wednesday, June 10th, 2009
5:45 – 6:15 PM – Mixer, group kickoff and speaker introduction
6:15 – 7:45 PM – Presentation
7:45 – 8:00 PM – Spillover time and raffle


Starbucks Support Center
2401 Utah Ave S.
Seattle, WA 98134
See Map

Our meeting is open to everyone so bring your friends and co-workers. 
If you’re planning to come, please RSVP as soon as possible via email or at the Facebook Group.

Barcamp Seattle June 13th - June 14th 2009

BarCampSeattle is an ad-hoc gathering born from the desire for people to share and learn in an open environment. It is an intense event with discussions, demos, and interaction from attendees. It is an international network of user generated non-traditional social conferences: open, participatory workshop-events, whose content is provided by participants, often focusing on early-stage web applications, and related open source technologies, social protocols, and open data formats. Oh and super fun!!

I will be going to this on Saturday to see how this type of event works. I always enjoy going to these types of things just for the networking opportunities.

To register and see more details visit:

Compress and Decompress using .net framework and built in GZipStream

I recently had a project in which I wanted to compress log files I was transferring between servers. I did not realize till I did some research that the .NET framework has a nice little library built in for creating GZIP files. While I think the maximum recommended size for using this is 4GIG I am well under that.

Here is my Compress / Decompress methods

byte[] startfile = File.ReadAllBytes("e:\\mylog.log");
byte[] comp = null;
byte[] decom = null;


comp = CompressBytes(startfile);

decom = Decompress(comp);


private void Compress(byte[] fileBytes)
using(MemoryStream ms = new MemoryStream())
using(GZipStream gz = new GZipStream(ms,
gz.Write(fileBytes, 0, fileBytes.Length);


private byte[] Decompress(byte[] fileBytes)
int buffer_size = 100;

using(MemoryStream ms = new MemoryStream(fileBytes))
using(GZipStream gz = new GZipStream(ms,
byte[] bufferFooter = null;
int readOffset = 0;
int totalBytes = 0;
byte[] finalBuffer = null;
int uncompLength = 0;
int compressedFileLength = fileBytes.Length;

// Get last 4 bytes (footer) as they contain the
// original length of the compressed bytes

// byte array to hold footer value
bufferFooter = new byte[4];

// Set position of MemoryStream end of stream
// minus the 4 bytes needed
ms.Position = ms.Length - 4;

// Fill the bufferFooter with the last 4 bytes
ms.Read(bufferFooter, 0, 4);

// Set Stream back to 0
ms.Position = 0;

// Convert footer bytes to the length.
uncompLength = BitConverter.ToInt32(bufferFooter, 0);

// Set a temporary buffer to hold the uncompressed
// information. We also make it slightly larger to
// ensure everything will fit. We will later trim
// off the unused bytes.
finalBuffer = new byte[uncompLength + buffer_size];

// Read from stream up to buffer size. Note that return
// value is actual bytes read in case the number filled
// is less than we requested.
int bytesRead = gz.Read(finalBuffer,

// If no bytes returned we are done
if(bytesRead == 0)

readOffset += bytesRead;
totalBytes += bytesRead;

// Trim off unused bytes based
Array.Resize<byte>(ref finalBuffer, totalBytes);

return finalBuffer;

Calling ASMX .net Web Service using jQuery

Just started to pick up jquery recently and was playing with calling a .net web service from my page. Was really easy once I used Firefox Firebug to do my debugging and figure out some of the variable names to use to access my data.

Here is my final code

Javascript in page

<script type="text/javascript">
$(document).ready(function() {
type: "POST",
url: "default.asmx/GetCatalog",
cache: false,
contentType: "application/json; charset=utf-8",
data: "{}",
dataType: "json",
success: handleSuccess,
error: handleError

function handleSuccess(data, status) {
for (var count in data.d) {
' <strong>Book:</strong> ' + data.d[count].BookName +
' <strong>Author:</strong> ' + data.d[count].Author +
                ' <br />');


function handleError(xmlRequest) {
alert(xmlRequest.status + ' \n\r '
+ xmlRequest.statusText + '\n\r'
+ xmlRequest.responseText);

and the div that I write the content to

<b>Books List</b>
<div id="bookTitles">

and my Web Service and Class Catalog

public Catalog[] GetCatalog()
Catalog[] catalog = new Catalog[1];
Catalog cat = new Catalog();
cat.Author = "Jim";
cat.BookName ="His Book";
catalog.SetValue(cat, 0);
return catalog;


public class Catalog
public string Author;
public string BookName;

Replacing text in a stream after writing

Recently I responded to a question asked on StackOverflow. The question was "What is the BEST way to replace text in a File using C# / .NET?"

Just by the question you might assume they were wanting to simply replace text in an existing file and of course you could do that by opening the file and looping over it or doing a Replace of content.

Here is the requirements they gave.

Have a text file that is being written to as part of a very large data extract. The first line of the text file is the number of "accounts" extracted.

Because of the nature of this extract, that number is not known until the very end of the process, but the file can be large (a few hundred megs).

What is the BEST way in C# / .NET to open a file (in this case a simple text file), and replace the data that is in the first "line" of text?

So as you can see they are in the process of writing the file, at the end of the write of the file they now know the information they wish to write at the top of the file. So how might we able to go back and write that information without having to open the file again and write the information at the top of the file?

It turns out it is actually fairly simple. One we want to make sure memory utilization is a factor since these files can be very large we probably do not want to open the whole file and prepend text, or do some kind of search and replace on text content that size. So my suggestion is using a stream. Also by using a Stream we can avoid entirely writing the file, then having to open the file again and write the text. StreamWriter has a BaseStream property that provides you access to the base stream object which then allows you to set the position of the stream back to the top and write out the information.

Here is my answer.

private void WriteUsers()
    string userCountString = null;
    ASCIIEncoding enc = new ASCIIEncoding();
    byte[] userCountBytes = null;
    int userCounter = 0;
    using(StreamWriter sw = File.CreateText("myfile.txt"))
        // Write a blank line and return
        // Note this line will later contain our user count.
        // Write out the records and keep track of the count 
        for(int i = 1; i < 100; i++)
            sw.WriteLine("User" + i);
        // Get the base stream and set the position to 0
        sw.BaseStream.Position = 0;
        userCountString = "User Count: " + userCounter;
        userCountBytes = enc.GetBytes(userCountString);
        sw.BaseStream.Write(userCountBytes, 0, userCountBytes.Length);


Seattle .net dotnet user group

Great new user group that is getting started and it is in Seattle. Was hosted at Starbucks who provided a top notch facility for the meeting. About 25 people showed up and  speaker Charles Sterling  gave us a great presentation walking us through the new testing tools in Microsoft Visual Studio Team Systems 2010. 

Highly recommend this to anyone involved in .NET development and located in or around Seattle.

They also have a facebook group

How do I open a file that is in use in C#?

I had a situation recently in which I needed to display in my application the log file that was being generated by the application which was using log4net. Any time I tried to open the log file I would get an exception because the file was in use. I searched google for the answer as I normally do and found many others trying to find the same exact answer. Some came up with ideas like copying the original file to another temporary file and opening it. Others seemed to reach a dead end. However I soon figured out what my issue was.

When reading my file using StreamReader it appears that while I assumed since I was reading the file it should not be an issue if it was in use since I was only reading it. Well that is were I was making my wrong assumption. It appears that the StreamReader object opens the file and tries to set an exclusive lock on the file while reading the contents. Since in my case another program already has an exclusive lock it would fail.

So I started to look at how I could open the file in truly a read only mode. While I found people talking again about opening a file in use for readonly access it was for some reason not clear to me what the exact solution was.

So what is the solution? System.IO.FileShare

By creating a FileStream object and setting FileShare.ReadWrite I am saying that I want to open the file in a mode that allows other files to Read and Write to/from the file while I have it opened.

Here is an example code snipet of how I read my log file that was currently in use by the logging object log4net. Hope this helps someone else.

private void LoadFile()
        using(FileStream fileStream = new FileStream(
            using(StreamReader streamReader = new StreamReader(fileStream))
                this.textBoxLogs.Text = streamReader.ReadToEnd();
    catch(Exception ex)
        MessageBox.Show("Error loading log file: " + ex.Message);

kick it on

Microsoft patterns & practices Application Architecture Guide 2.0

Was listening to a podcast the other day in which one of the authors of the Microsoft patterns & practices Application Architecture Guide was speaking about this latest version so I decide to take a look. So far I am very impressed as the information seems to do a fairly good job of coupling desgin guidlines for applications with some of the latest technologies.

The guide breaks architecture down into 4 parts.

Part I - Fundamentals

  • Fundamentals of Application Architecture
  • .NET Platform Overview
  • Architecture and Design Guidlines

Part II - Desgin

  • Designing Your Architecture
  • Deployment Patterns
  • Architecture Styles
  • Quality Attributes
  • Communication Guidelines

Part III - Layers

  • Layers and Tiers
  • Presentation Layer Guidelines
  • Business Layer Guidelines
  • Data Access Layer Guidelines
  • Service Layer Guidelines

Part IV - Achetypes

  • Application Archetypes
  • Web Applications
  • Rich Internet Applications (RIA)
  • Services
  • Mobile Applications
  • Office Business Applications (OBA)
  • SharePoint LOB Applications

Also the Appendix offers some great advice using a Matrix apporoach to various technologies.

Data Technology Matrix - Provides matrix of old and new technology options such as ADO.NET, Entity Framework, LINQ to SQL and more.

Check out the website on codeplex

Also here is a link to pocket guides based on the Application Architecture Guide but geared towards Web Architecture, Mobile Architecture, RIA Architecture, Rich Client Architecture, Service Architecture.

Check out pocket guides on codeplex

Understanding .NET Reference Types and Value Types

I have been developing in .NET now for about 4 years and while I have visited this topic many times I have not always fully understood things. Dealing with Value Types is really straight forward however when we start to get into Reference Types things become a bit clouded. Well I have recently been forced to try and explain them to someone else and so I decided it was time to make sure I fully understand things. So this is my attempt to provide based on things I have read and learned how things work.

 I will start by simply making some statements that will later help us understand things.

Value Types - Stored on the stack. When you declare a variable based on a value type, the CLR allocates memory for the value type instance wherever the variables is declared.

Reference Types - Variable declared is stored on the stack. When you declare a reference type, the CLR allocates memory for instance on the heap.

Reference Types with Value Types: When declaring inside a reference type a field that is a value type it is important to note that the memory is allocated inside the hosted object.

-----------     ------------
-  stack  -     -  heap    -
-----------     ------------
-  var1   -     -  Class1  -
-----------     - Instance -
-   10    -     ------------
-----------           ^
-  var2   -           |
-----------           |
-   ref   - -----------

Strings - It is important to point out that strings are immutable. When making changes to a string you are actually creating a new instance of that string. You will see in the examples below that they behave a little different when making changes to them as opposed to making changes to a field in a Class.

Memory Cleanup:

  • Value Types - When a value type goes out of scope the memory is immediatly removed from the stack.
  • Reference Types - When a reference type goes out of scope the variable is immediatly removed from the stack. However the memory allocated on the heap still exists and the removal is managed by the Memory Manager and Garbage Collector process.

 Methods: Passing arguments to methods ByValue and ByReference When you declare a method you by default pass in the argument ByValue. However the behaviour giving this statement is not always as expected when dealing with reference types. Here are some scenarios.

  • Value Type being passed ByValue: Remember that a value type holds the data itself. When passing in ByValue a copy of the actual data is passed. The method now contains its own variable and data and so the result is that the original variable will not change as changes are made to the new variable inside the method.
  • Value Type being passed ByReference: When passing in a value type ByReference we are actually passing a reference is created that points to the data. The result is that any changes made to the variable inside the scope of the method are reflected back to the external variable.
  • Reference Type being passed ByValue: When you pass in a reference type ByValue you get a bit  different behaviour. Remember that the value is always on the heap, so you are actually pointing the new variable to the same memory location as the original variable. Thus when making changes to the variable changes are reflected to the original variable. So if you need to pass a reference type and not have changes reflected you need to make sure you create a full new copy of the object being passed in.
  • Reference Type being passed ByReference: This last situation you most likely want to avoid. This basically ends up creating a reference variable that points to the reference variable that points to the data. So a reference to a reference. While I said you usually should avoid this it is worth pointing out why you might want to use this approach. Remember that in the  previous Reference ByValue changes are reflected back to the original variable. However if you make any changes to the object itself, for example set the object to NULL or set it to a NEW object then the changes would not be reflected outside as your internal variable now points to a new memory location. So if you need to have NEW or NULL changes reflected back outside you could pass it in ByRef.

 Below you will find some examples that will help see how value types and refernce types differ when making changes to them and how the behaviour changes when passing them into methods.

STRING TEST - Reference Type - Immutable
Creating two strings. Setting the first to the value "one-before" and then initializing the second variable by pointing it to the first. Writing out the initial values so that we can see that each is now set to "one-before". So at this point what we have in effect is to variables declared on the stack one and two that both point to the same memory location which holds "one-before". Then we come along and we set one = "one-after" and since strings are immutable a new memory locations is allocated and one is now pointed to the new memory location. However two still remains pointed to the previous memory location so the result is that they now have different values.

//Begin Test
string one = "one-before";
string two = one;

Console.WriteLine(one); //Output = one-before
Console.WriteLine(two); //Output = one-before

one = "one-after";

Console.WriteLine(one); //Output = one-after
Console.WriteLine(two); //Output = one-before
// End Test

Creating two integers. Setting the first to the value 1 and then initializing the second variable by pointing it to the first. Writing out the initial values we see that both variables have the same value of 1. The next thing we do is change the value or i = 2. Then we write out the values of the variables and see that i = 2 but j = 1. The reason for this is that value types when assigned a value contain the actual data. So when we created j = i we got a copy of the actual data that i contained and j now has its own data. So when we come along later and make a change to i we are only changing its information and j will still reflect the information it holds.

// Begin Test
int i = 1;
int j = i;

Console.WriteLine(i); // Output = 1
Console.WriteLine(j); // Output = 1

i = 2;

Console.WriteLine(i); // Output = 2
Console.WriteLine(j); // Output = 1
// End Test

To be continued. Will be adding tests for passing into methods Structure (ValueType) and Class (ReferenceType)