My name is Justin Kohnen, and I’m a Geek.

CODODN 2009 Registration is open!

noreply@blogger.com (Justin Kohnen) — Wed, 18 Mar 2009 06:34:00 +0000

Registration for the Central Ohio Day of .NET is now open. Quick sign up while spots are still open.

The Central Ohio Day of .NET is a joint venture between the Dayton .NET Developers Group, Central Ohio .NET Developers Group, Cincinnati SQL Server Users Group and the Cincinnati .NET Users Group. The event is a FREE day of technology discussions devoted to helping the local development community grow. Please check back often for more information about Day of .NET events.

If you need additional information please visit the official website.

If you want to track the event start following @CODODN on Twitter. Or keep an eye on the hash tags.

And since I'm the board member in charge of marketing for the event, help me spread the word.

Tweet it on Twitter
Download the flyers and print some off to hang around the office
Blog about it
- Don't forget your blog bling. Wear your badge with pride:
  <a href="http://www.cinnug.org/cododn"><img style="border-top-style: none; border-right-style: none; border-left-style: none; border-bottom-style: none" src="http://www.cinnug.org/images/cododn2009Badge.gif" border="0" /></a>
Tell your friends, your mother, your cats, and dogs.

A great event is coming up.... don't miss it. Register Today!

Software Development Trueisms

noreply@blogger.com (Justin Kohnen) — Tue, 17 Mar 2009 14:47:00 +0000

A co-worker sent these to me, and I thought they were hilarious and instead of spamming people I thought I would post about it.

Walking on water and developing software from a specification are easy if both are frozen.
Program complexity grows until it exceeds the capability of the programmer who must maintain it.
Users don’t know what they really want, but they will know when they see it…
The degree of normality in a database is inversely proportional to that of its DBA.
If you work on a program long enough, it will eventually send E-mail.
Technology is dominated by two types of people: those who understand what they do not manage, and those who manage what they do not understand.
If you want software made you have 3 options: You can have it done FAST, you can have it done RIGHT, You can have it done CHEAP. Pick 2.

CAPTCHA Tool for Protecting Email Addresses

noreply@blogger.com (Justin Kohnen) — Wed, 04 Mar 2009 05:27:00 +0000

This post is a continuation of my previous post. "Some tips and tricks to prevent Email Harvesting / Scraping"

One of the techniques I mentioned was an "Anti-bot" process and I made reference to the Google Groups CAPTCHA design.

Today I found out that reCAPTCHA.net offers the same service for free. It's called Mailhide

Just browse out to http://mailhide.recaptcha.net/, supply an email address, and they will provide you with HTML you can use to mask your email.

Here's the process with pretty pictures

Providing an email address.

The generated HTML

Once the HTML is embedded, clicking the "..." gives you

When you provide the correct input you get

Pretty cool huh?

Give it a try yourself: User...@Domain.com

They also have an API available if you want to do the same process in bulk.

Happy coding.

Virtualization: My experience installing VMware ESXi 3.5.0

noreply@blogger.com (Justin Kohnen) — Sun, 01 Mar 2009 19:26:00 +0000

What is VMware Server ESXi?

When you're using visualization usually you need a host operating system that your virtual machines (VM's) will run on top of. With ESXi, the need for a host OS is removed.

"With a General Purpose OS, the VM's are only as reliable as the host OS. So if the host OS crashes or needs to be patched all the VM's on the machine are affected." ESXi removes these problems. In addition ESXi only has a 32MB footprint, therefore using less resources and having a smaller surface area for attack.

If you want to learn more, check out the VMware ESXi Online Demo.

Now let's begin my experience installing ESXi 3.5

Installation

First problem I ran into was trying to get the installer to actually run. I kept getting an error when the installer tried to start, "Unable to find a supported device to write the VMware ESX." Turns out, VMware ESXi won't install to an IDE hard drive with it's standard configuration. After some Googling I found a post in VMware's community forum which pointed me to the solution to my problem.

"Install ESXi 3.5 to an IDE drive"

Now I was able to successfully complete the rest of the install process.

Configuration

Second problem I hit was when I was trying to configure the "Management Network". I wanted to give a static IP address to my ESXi server. Every time I tried to enter the menu I was repeatedly asked to "Restore network factory settings." This time I learned the config menu does weird things if it encounters hardware it doesn't support. (In this case my motherboard's onboard NIC.) Google and Expert Exchange helped me find this answer.

"What storage and network devices will ESXi 3.5 recognize?"

I installed a different NIC and was able to successfully complete the the rest of the configuration process.

Client Installation

I then connected to my new ESXi's IP via http in a web browser, and downloaded/installed the "VMware Infrastructure Client". (This thru me for a loop too, the install manual never said how you got a copy of the infrastructure client.)

Adding a storage device

The next hurdle I had to jump was when I tried to add my WAMP VM via the "Import a virtual appliance" feature. The moment I would click on the feature, I would get an error "Index was out of range. Must be non-negative and less then the size of the collection. Parameter name:index"

This error I figured out by poking around. The problem was because I didn't have a data source configured yet. I had to configure one thru the "Configuration" tab. Heh, go figure. :-P (Once again, something the installation manual kinda missed.)

So I put the server in "Maintenance Mode" and did the following.

Once I was done, I brought the server back out of "Maintenance Mode," and the error was gone.

Importing a Virtual Machine

Justin, so you're done right? Well almost, yes my server was ready, but I still needed to add my VM to it. The last issue I ran into was when I again tried to import my WAMP VM using the "Import a virtual appliance" feature. The WAMP VM is a VMware Workstation VM, and Workstation VM's are not compatible with VMware Server ESXi.

To solve this problem I had to use another tool from VMware. The VMware vCenter Converter. I used the "Import Machine" feature of the converter to import my Workstation VM into my ESXi server.

After the conversion/import process was done, SUCCESS!!! I now have my WAMP VM running on my ESXi server.

Now wasn't that easy?

Where can I download old versions of JetBrains' ReShaper?

noreply@blogger.com (Justin Kohnen) — Wed, 10 Dec 2008 20:17:00 +0000

Often times I've tried to find old version of JetBrain's amazing tool ReSharper (R#). Usually I have to settle with some download site. Which makes me feel a little uneasy. The other day I found the JetBrains' provided link. So I figured I would share with the world.

http://www.jetbrains.net/devnet/docs/DOC-280;jsessionid=3B8C7B3BA56CA355357DE8E5437485E9

The "var" keyword works in .NET 2.0?

noreply@blogger.com (Justin Kohnen) — Tue, 04 Nov 2008 02:51:00 +0000

Just the other day I installed Resharper 4.1 into my copy of Visual Studio 2008. Once I loaded my .NET 2.0 web application Resharper started suggesting I replace my variable type declarations with "var"!

What's this? Isn't "var" a C# 3.0 (.NET 3.5 Framework) feature?

So for giggles I swapped int for var and did a solution build (Ctrl + Shift + B).

NO ERRORS!

I ran the web application.

NO ERRORS!

So I posed a question to my twitter friends.

Why is my C# project for 2.0 framework, compiling fine with "var"?

Turns out, it's all Visual Studio 2008 slight of hand. As Phil Japikse says:

@JustinKohnen it's syntactic sugar in VS2008. If you look at the IL, it compiles down to 2.0 compatible code.

Isn't that interesting? You can also use automatic properties, and object initializers too! After Phil opened my eyes, he wrote a great blog post about these Visual Studio 2008 Compiler Tricks.

A thanks to Phil Japikse, Leon, and Matt Brewer for the help.

FYI: I'm changing my feed URL

noreply@blogger.com (Justin Kohnen) — Fri, 22 Aug 2008 20:27:00 +0000

I just wanted to give my RSS people a heads up. Some time in the next few months I will be shutting down my old feed URL.

My new URL is:
http://feeds.feedburner.com/JustinKohnen

Please switch over when you get a chance. I'd hate to lose you as a reader.

Kindest Regards,
Justin Kohnen, Geek

When do browsers download images defined in Cascading Style Sheets?

noreply@blogger.com (Justin Kohnen) — Tue, 12 Aug 2008 03:59:00 +0000

Just the other day I was talking with a coworker about ASP.NET Themes. We were addressing a question about putting multiple Cascading Style Sheets (CSS) into a theme.

Unless you do something special, ASP.NET Themes adds a link reference to every CSS file in the theme directory. We were fine with this behavior even if the styles weren't used by the page, but what about all the background images defined in the style sheets?

Here's where we asked the question "When do browsers download images defined in Cascading Style Sheets?"

Here are my findings:

Both Internet Explorer 7 and FireFox 3.0 do not download an image unless the style is used on an element of the page.

For Example:

Consider a style sheet called style.css which containes

.image
{
 background:transparent url(testImage.png);
}

If you have a html file which contains:

<html>

    <head>

        <link type="text/css" rel="stylesheet" media="screen, projection" href="style.css">

    </head>

    <body>

        <p>Hello World</p>

    </body>

</html>

There will be two requests to the server: html, and css

If you have a html file which contains:

<html>

    <head>

        <link type="text/css" rel="stylesheet" media="screen, projection" href="style.css">

    </head>

    <body class="image">

        <p>Hello World</p>

    </body>

</html>

There will be three requests to the server: html, css, and png

I tested using FireFox 3.0 with FireBug (HEH HEH, FIRE!), and Internet Explorer 7 and Fiddler.

ASP.NET Development Tips/Tricks: Using "Attach to Process..."

noreply@blogger.com (Justin Kohnen) — Sat, 09 Aug 2008 02:55:00 +0000

I wanted to save this tip for later but I think it's too important to hold back. The one action of attaching to a process will save you minutes, that's right MINUTES, in your daily tasks.

You might have noticed in my last post about Keyboard Shortcuts I never mentioned the F5 key. That's because I never use it.

The F5 key is commonly used to "Start Debugging." Let's take a moment to walk thru what happens when you press F5. (Or click the green play button, or thru the menu Debug > Start Debugging)

The F5 Way

First, Visual Studio (VS) will build your startup project.
Second, VS opens an instance of your configured browser and attaches to the browser's process.
Third, VS will direct the browser to the start page of your start-up project.
Forth, VS finally attaches to the process hosting ASP.NET

w3wp.exe if you use IIS6
aspnetwp.exe if you used IIS 5.5
WebDev.WebServer.exe if you use the ASP.NET Development Server that comes with Visual Studio.

Now, lets assume you want to debug some new administrative feature you've added to your web application. After all of the "F5" steps, most likely you:

Fifth, start on your start page (I'll assume Default.aspx)
Sixth, click on the Login link
Seventh, login with Username and Password
Eighth, browse to the Administration page with the feature you want to test

Now, lets assume you have a bug in your code. Your next step might be:

Ninth, close the browser
Tenth, change the code to fix the bug
Goto First

The "Attach to Process..." Way

So, how can "Attach to process... " save you minutes? By not repeating the Second, Third, Fifth, Sixth, Seventh, Eighth, and Ninth steps from above.

Here is the process I use:

Once per day:

Open Browser
Browse to development website

If Root: (http://localhost)
If Virtual Directory: (http://localhost/vDirectory)

Click Login link
Login with Username and Password
Browse to the Administration page where the new feature will be

That's right, I usually only do these 5 steps once a day.

Now, I write my new administrative feature. Then, it comes time to test my changes.

<note>
This is where my first three common "walks" of my last post become important.
</note>

First, build the current web project if needed.

(Alt, B, U)

Second, attach to process hosting ASP.NET.

w3wp.exe (Alt, D, P, W 3, Enter)
aspnetwp.exe (Alt, D, P, A S P, Enter)
WebDev.WebServer.exe (Alt, D, P, W E B, Enter)

Third, switch to the open browser

(Alt+Tab)

Fourth, refresh page as appropriate

(F5 or Ctrl+F5 or Alt+D, Enter)

Lets assume there is a bug in my new code. (I know it's hard to believe, but just for giggles lets assume.)

Fifth, detach from the process hosting ASP.NET

(Alt, D, D, [sometimes Enter])

Sixth, change the code to fix the bug
Goto First

Conclusion

By using "Attach to Process..." we save ourselves repeatedly launching and closing the browser, the login process, and the preliminary navigational steps to get to the code we want to test. These actions which took minutes and were repeated with every "F5" now are only done once.

For the lovers of techno and "The Orange Box: Portal"

noreply@blogger.com (Justin Kohnen) — Thu, 07 Aug 2008 02:33:00 +0000

I'm a developer that cannot code without music. Euro Dance Techno from di.fm is this ninja's weapon of choice. I don't think I could work for a company that didn't let me have my headphones.

Just the other day I can across a remix of "Still Alive" from the credits of "Portal" the video game. (Part of The Orange Box).

I wanted to give a shout out to Raddox for his mix, and let others know about some of his other awesome work. Namely, "I'll Follow You There," and the amazing "When I Was a Child."

Happy coding to all.

ASP.NET Development Tips/Tricks : Know your Keyboard

noreply@blogger.com (Justin Kohnen) — Mon, 04 Aug 2008 23:06:00 +0000

I've thought for a while about what tip I wanted to start with. I decided to begin with the keyboard because I'll mention what shortcuts I use in all future tricks.

I don't want to get into a debate of which is better "the keyboard" or "the mouse", (personally I use one to compliment the other) but there are a some things about your keyboard and Visual Studio (VS) that can shave a few seconds off your common daily tasks. I like to call these two tips "VS Keyboard Shortcuts" and "Walking the Menus."

VS Keyboard Shortcuts

Everyone should know Visual Studio IDE largely relies on the Command Pattern. Nearly every action in VS can be performed by a command, and most Add-ins rely on the command pattern too.

What does this give us? Two words: "Keyboard" "Shortcuts." You can essentially tie any command (save, build, copy) to a key combination. These settings are controlled in the keyboard options dialog.

Tools > Options > Environment > Keyboard

In this dialog you can lookup all the commands, and assign key combinations to them.

If you see a command with a comma (',') in it, this means you pause.

For example "Ctrl+K, Ctrl+K" means hit "Ctrl+K" pause hit "Ctrl+K" again. Or, hold down the "Ctrl" key and hit the "K" key twice.

Some of the most common VS shortcuts I use are:

Ctrl+X	Cut
Ctrl+C	Copy
Ctrl+V	Paste
Ctrl+Z	Undo
Ctrl+Shift+Z	Redo
Ctrl+S	Save
Ctrl+G	Go to line
Ctrl+Shift+B	Build Entire Solution
Ctrl+K, Ctrl+K	Add/Remove Bookmark
Ctrl+K, Ctrl+P	Go to Previous Bookmark
Ctrl+K, Ctrl+N	Go to Next Bookmark
Ctrl+M, Ctrl+O	Collapse all (regions, methods, etc.)
Ctrl+M, Ctrl+P	Expand All (regions, methods, etc.)
Ctrl+M, Ctrl+M	Collapse/Expand Current
Ctrl+K, Ctrl+C	Comment out Current Line or Selection
Ctrl+K, Ctrl+U	Uncomment Current Line or Selection
F9	Add/Remove a breakpoint on the current line

Most of the common commands appear in the menus for quick reference.

Some general non-VS shortcuts I also use:

Alt+Tab	Switch windows.
Ctrl+Right Arrow	Jump one "word" to the right
Ctrl+Left Arrow	Jump one "word" to the left
Ctrl+Shift+Right Arrow	Un/Highlight one "word" to the right
Ctrl+Shift+Left Arrow	Un/Highlight one "word" to the left

Walking the Menus

Now, spend a few minutes exploring your menus and context menus. Look at all those commands and command categories. (Most having an underlined letter)

Using your Alt key and those underlined letters you can "walk the menus."

When you hit Alt, the menu bar gets focus. Use the letter shortcuts (the underlined letter) to select the action you want. This keeps you from taking your hands off your keyboard to grab the mouse to click the menus.

Some of my common "walks" are:

Alt, B, U	Build Current Project (the project containing the document your working on)
Alt, D, P	Attach the VS Debugger to a Process
Alt, D, D	Detach the VS Debugger from all Processes
Alt, W, L	Close all Documents/Tabs

The first three don't seem like much, but I'll explain how valuable they are in a later post.

Conclusion

The process of taking your hand off your keyboard home row, grabbing the mouse, dragging to target, clicking (repeated clicking if you have bad aim), and moving your hand back to the home row takes valuable seconds. Why not save them by learning a keyboard trick or two?

RadComboBox not working within a ModalPopupExtender

noreply@blogger.com (Justin Kohnen) — Wed, 30 Jul 2008 16:51:00 +0000

I just figured out a problem I was having with a Telerik RadComboBox within a ModalPopupExtender and I thought I would share.

The Extender worked fine, but when I clicked on the ComboBox the sliding drop down would not show.

Turns out all the controls were working just fine, it was a CSS problem.

By default the ModalPopupExtender div is set to a z-index of 100001. The RadComboBox slide div is set to a z-index to 6000. Essentially, the slide div was under the popup div.

You can fix the problem by boosting the z-index of the slide div.

I did it with jQuery:

$(document).ready(function ()
{
 $("div.rcbSlide").css('z-index', 100002);    
});

"ASP.NET Development Tips/Tricks" are coming!

noreply@blogger.com (Justin Kohnen) — Tue, 29 Jul 2008 04:18:00 +0000

During my years of developing in Visual Studio and ASP.NET, I've learned a few things here and there which helped me become more efficient when creating applications.

At the risk of sounding stupid, I'm going to share with the community some tricks I've learned. I don't know how many posts there are going to be, but I hope something I say might have value to someone else.

Some tips and tricks to prevent Email Harvesting / Scraping

noreply@blogger.com (Justin Kohnen) — Sat, 19 Jul 2008 05:54:00 +0000

First a little background for those of you that don't know. The term Email Harvesting or Email Scraping comes from the trick some spammers use to get valid email addresses.

Overly simplified, harvesting works as such: Some automated program goes out to web pages and looks over the source HTML for text that matches email formats (name@domain.com or mailto:name@domain.com). This software then stores matches to a database for spamming later.

<rant>
Web developers pay attention, nothing erks me more then web sites that post my full email address for all to scrape. I don't think I'm the only one that feels this way.
</rant>

So how do you prevent your email from being harvested?
Here a couple of suggestions:

Be creative with how you present your email address so they don't match the standard format.

Examples include:

name at domain dot com
name shift+2 domain period com
String.Format("{0}@{1}.com", "name", "domain");

Use some type of masking javascript to obscure the email address
- Example: (tool used: about.com:Javascript)

Use HTML encoding of some flavor
- Example: (tool used: about.com:Javascript)

Use an anti-bot process
- Example: (Google Groups)
  - Clicking on the ellipse (...) of the email takes you to a CAPTCHA form

Use an email friendly URL shinker
- Example: (tool used: http://is.gd)
  - Entered "mailto:name@domain.com"
    and got http://is.gd/XBs
    (try it - you should experience the standard behavior of a "mailto," usually launching an email client)

Of course this is all a cat and mouse game. The harder we make it to harvest our email address the smarter the automated software becomes to figure it out our obfuscation. We just got to stay a step ahead of that darn cat.

<disclaimer>
I offer my advice with not warrantee or guarantee. Feel free to run with anything, but use at your own risk.
</disclaimer>

Use Exception.ToString() instead of Exception.Message

noreply@blogger.com (Justin Kohnen) — Wed, 11 Jun 2008 03:18:00 +0000

All too often I see code that tries to log exceptions to some type of persistent storage for and later reference and error/bug tracking. Some might not be aware, but the second worst thing you can log is Exception.Message. (The first being "An error occurred.") What should you use instead? Exception.ToString()

There is a world of difference between the two. Here's an example:

        1: public partial class Default : System.Web.UI.Page

       2: {

       3:     protected void Page_Load(object sender, EventArgs e)

       4:     {

       5:         try

       6:         {

       7:             int zero = 0;

       8:             int divisionbyZero = 42 / zero;

       9:         }

      10:         catch (Exception caughtException)

      11:         {

      12:             System.Console.WriteLine(caughtException.Message);

      13:             System.Console.WriteLine(caughtException.ToString());

      14:         }

      15:     }

      16: }

When I debug, here is what I get from line 12:

Attempted to divide by zero.

And from line 13:

System.DivideByZeroException: Attempted to divide by zero.
   at Demo.Web.Default.Page_Load(Object sender, EventArgs e) in C:\Working Copies\Demo\Demo.Web\Default.aspx.cs:line 23

Which would you rather see in a system error log?

My recommendation when writing to an error log "Use Exception.ToString() instead of Exception.Message."

Recap: Brian H Prince on "Soft Skillz" for developers

noreply@blogger.com (Justin Kohnen) — Sat, 05 Apr 2008 16:11:00 +0000

Recently at the Dayton .NET Developers Group Brian H. Prince gave a presentation titled "Soft Skillz. Geeks Need 'em Too"

Got to say, I thought the presentation was great. Had good humor, and Brian's passion for the subject matter really shines thru.

What did I get out of it?

One of the biggest things to stick is not all mentors have to be technical mentors. You can learn a lot from managers, sales reps, even from your clients.

He also mentioned you need to keep reading. Read at least one book a month, and mix it up a bit. Read about other subjects, not just technical. Exploring these other areas will help you think of new ways to write your code.

I could keep going but I don't want to spoil too much for developer's attending the CODODN.

If you're coming to the Central Ohio Day of .NET (CODODN) make sure to set some time aside for Brian's "Soft Skillz" presentation.

.NET 3.5 LINQ and Inner, Outer Joins

noreply@blogger.com (Justin Kohnen) — Wed, 02 Apr 2008 00:10:00 +0000

During my Visual Studio 2008 Install Party presentation at the Dayton .NET Developers Group. Someone asked the question

"Can you do joins with LINQ?"

I thought I would share a great blog post from K. Scott Allen titled: Inner, Outer, Let's All Join Together With LINQ.

Using Windows Live Writer for Blogging

noreply@blogger.com (Justin Kohnen) — Mon, 25 Feb 2008 05:46:00 +0000

Some of you may have noticed my blog posts have actually increased as of late. Why? I used to use Blogger's online editor and the trouble I had with it really pushed me away from writing posts. I want my posts to look just the way I want, and the editor kept taking liberties with my visual formatting. SO FRUSTRATING!

So I posted the query to Twitter:
"I'm taking a poll: What is your favorite blog editor?"

Since then I've started using, you guessed it, Windows Live Writer.

So far I'm loving it, every post I've made matches the preview. Just like a WYSIWYG should. I've also started playing with the "Plug-ins."

I've recently added Insert Code Plug-in. Awesome! No more images of code for me. Here's a sample of what it does:

Inserting HTML Code (but I'm using XML):

<?xml version="1.0"?>
<configuration>
    <system.serviceModel>
        <services>

Inserting C#:

public static void SomeMethod(string someString)
{
  Console.WriteLine(someString);
}

Inserting TSQL:

CREATE PROCEDURE someStoredProcedure
  @someMsg varchar(256) = NULL
AS
BEGIN

I can only imagine what other tools will be coming out in the future. So for right now Windows Live Writer is for me.

Cincinnati Users Group and the Version Control Panel

noreply@blogger.com (Justin Kohnen) — Wed, 20 Feb 2008 06:48:00 +0000

Well I just finished up being part of the Source Control Panel at the Cincinnati Users Group.

I was very enjoyable. I think I did a fine job representing Subversion. Those of you that read my blog know that I got a good understanding of the system and methodology.

For those that are interested, I tend to tag allot of my research

Actually, I was quite surprised there weren't more questions about "Version Control Best Practices," "Branching Options," and "Database Versioning"

At the end there was much discussion about the "additional features" of TFS. I thought that was a bit unfair to SVN. SVN was designed to be nothing more then Version Control. Do one thing, and one thing well, right?

<PersonalOpinion>

Sure SVN doesn't have the "baked in" features like TFS does (and I'll admit TFS' integration is awesome) but with a few extra steps you can have work item tracking with trac. If you want Continual Integration you can always run CI Factory. If you want a better repo viewing experience you can install Fisheye. If you want code review you can run Crucible. With Subversion you have so many options.

Actually, I think being able to "choose" which tools you want to mix and match is a huge perk of using SVN. However, you do have to write the "glue" that holds it all together.

</PersonalOpinion>

All in all I had a really great time. There were a flurry of good questions and conversation. In the end, I just hope I helped someone learn something.

Remember,

Any version control is better then no version control.

P.S. If you have any additional questions about version control, ask away. I would be happy to address them.

Regular Expression Negation for Required Field Validators

noreply@blogger.com (Justin Kohnen) — Tue, 19 Feb 2008 15:35:00 +0000

Out of the box ASP.NET regular expression validators have the following behavior:

Does control value match regular expression? If yes validation passes, else validation fails.

But what if you wanted the following:

Does control value NOT match regular expression? If yes validation passes, else validation fails.

Turns out there is no "If expression not match" property on a regular expression validator. Now, you can make your own custom regular expression control, or you can buy a toolset. But it turns out you might be able to do it in your regular expression itself.

This can be accomplished by using something called a Negative lookahead assertion. It succeeds if the contained expression doesn't match at the current position in the string.

The syntax is

(?!&lt;value>)

For example, say you wanted to prevent users from using an email address that contained "@spam.com". You could use the following RegEx:

*@(?![Ss][Pp][Aa][Mm][.][Cc][Oo][Mm]$).*

Now your regular expression validator will pass if their value does NOT match the regular expression.

Regular Expression are extremely powerful, and I encourage everyone to learn about them. If you can master them, consider yourself a superhero.

Visual Studio 2008 Tour and Install Party

noreply@blogger.com (Justin Kohnen) — Mon, 18 Feb 2008 01:24:00 +0000

This month (February 27, 2008 18:00) I'll be speaking at the Dayton .NET Developers Group about Visual Studio 2008 and .NET 3.5.

The official blub is:

Visual Studio 2008 and .NET 3.5 are soon to be released, after a very public and open beta process. We will run around the products, and discuss what the new features are. This will briefly cover VS, WCF, WF, C# and VB.NET features.

<RandomSideNote>
I'm actually filling in for Brian Prince, who was filling in for Jeff Blankenburg. Both of whom are very busy men. Being that I'm a single guy, with no kids, or pets I figured I could jump in and help out. People seemed to be excited about this upcoming meeting, I just couldn't let it be canceled.
</RandomSideNote>

I'll be on the Source Control Panel on February 19, 2008 18:00

noreply@blogger.com (Justin Kohnen) — Sun, 17 Feb 2008 00:28:00 +0000

The Cincinnati User's Group (Cinnug) has asked me to be a part of the "Source Control Panel" they are having on Tuesday February 19, 2008 at 1800.

This meeting is different then those I've been in before. It's an open panel for group members to come and ask questions about VSS, TFS, Harvest, ClearCase, Vault and Subversion.

I'll be there primarily as a Subversion resource, but I'll try to fill in on VSS and TFS where I can.

Short notice I know, but if you're not doing anything Tuesday, come on down an heckle me. I think it's going to be a lot of fun.

Central Ohio Day of .NET - April 19, 2008

noreply@blogger.com (Justin Kohnen) — Sun, 17 Feb 2008 00:12:00 +0000

It's that time again. Time for us developers to get together and geek out to the latest technology and see who's smarter. ;)

Day of .NET events are a series of mini-conferences organized by developers for developers. The event it FREE to to all.

Visit the event's homepage, and register today.

For those that have attended the Dayton Cincinnati Code Camps of the past, this year we've included the Columbus .NET user group as well. Because "The Central Ohio Dayton Cincinnati Code Camp" was just to much to say, and CODCCC had just too many C's. The name has been changed to "Central Ohio Day of .NET", or CODODN. Ah, just better.

But seriously, becoming part of the Day of .NET events makes it easier for coders to find us, and helps coders find similar events going on in their areas.

Though the name may be different, it's the same great event. So come, meet new people, share ideas, socialize, and maybe learn something too.

Getting a list of .NET exceptions with Resharper.

noreply@blogger.com (Justin Kohnen) — Wed, 13 Feb 2008 15:22:00 +0000

Often I'm programming C#.NET and want to throw an exception but I don't know what exception to throw. I think "wouldn't it be nice if there was an easy way to get a list of the exceptions in .NET?"

I've Googled, I've dug thru the MDSN, then it hit me...

DUH! Resharper's intellisense.

A simple "throw new" gives you:

And you can use the "Navigate from here to Base" feature to get a more detailed list.

Just type "System.Exception" and hit the Resharper 2.x shortcut: Ctrl + Alt + B

Parsing a URI / URL in C# and VB.NET

noreply@blogger.com (Justin Kohnen) — Tue, 05 Feb 2008 20:09:00 +0000

I used to spend time parsing a URL string using old fashion .NET string methods. (Contains, Split, Substring, IndexOf, etc). I always thought, "There must be a better way to do this."

And there is, there is a tool in the .NET Framework to help you parse a fully qualified URI path.

System.UriBuilder

A few simple lines of code

Does a lot of the work for us.

And this is just one of the Uri tools. I encourage you to look at the others as well.

System.Uri
System.UriComponents
System.UriFormat
System.UriHostNameType
System.UriIdnScope
System.UriKind
System.UriParser
System.UriPartial
System.UriTypeConverter