Having Two Consecutive Hyphens in XHTML Comments Causes Anomalies in Firefox

Check out my experiment page to see the different side effects this issue causes.

If you're seeing weirdness when having hyphens in your (X)HTML comments, it's most likely because you're using two adjacent to each other, which is a big no-no according to the W3C.

Avoid using hyphens in your comments to avoid the issues... dumb, but required.

I know we're all prone to yell at Mozilla and tell them they're doing it wrong, because all the other latest versions of other browsers will still honor the comments, but Firefox isn't necessarily doing it wrong, because as I understand it, they're allowed by the standard to not honor the comment if there are two adjacent hyphens together.  In one way I think it's good that Firefox doesn't, because it forces we, the web authors, to follow standards.

On the other hand, I think the standard is flawed and that nothing between the start and end of a comment should matter... so part of me wishes Firefox would do like the other browsers and still honor the comments.

Oh well, go the safe route and keep hyphens out of your comments.

Visual Studio 2008 Crashes When You Stop Debugging After Rearranging Windows

I don't know what caused it... but somehow I managed to get Visual Studio 2008 in a state where it would crash if I tried rearranging debug and properties windows, etc and then later stopped the debugger.  Not only did it crash, but the app hung and would only close if I opened Task Manager and killed the devenv.exe process.

I started hunting and found this hotfix on MSDN, but then noticed in the comments a nicer solution to try before applying the hotfix.  The solution is simple:

1. Start debugging
2. Window >> Reset Window Layout
3. Stop debugging

This worked great for me... your mileage may vary.  If it doesn't work, try downloading the hotfix.

Introducing document.queryString for JavaScript

I got sick of not having a quick/easy reference object in JavaScript for getting a query string parameter's value.  JavaScript has always offered the window.location.search property to get the entire query string, but who wants to parse that every time?

So I set out to see how long it would take me to make a quick parser that would load it into a nice object that I could jam on the document.

Roughly 30 minutes later, I had one.  It also handles param names that contain periods (person.firstname) which is nice for those that do that with their ASP.NET MVC projects.

I don't have any docs yet, but see the quick write up at my JavaScript Jedi website if you'd like to see it in action and perhaps try it for yourself.

Enjoy!

Syncfusion MVC Grid - Prevent "A potentially dangerous Request.Form value was detected from the client" error

While working on an ASP.NET MVC project, using the Syncfusion Essential Grid for MVC, we had two pages utilizing the grid.  One page worked fine for displaying the data and paging/sorting.

The other page would show the results, but would fail on the AJAX calls back for paging/sorting.  It baffled me for several hours.  I compared all the settings between the two pages and I couldn't detect any differences between how each was set up.

I finally got frustrated and launched the site in Firefox, using Firebug to monitor the requests.
Props to Firebug, as it was the key to helping me find the solution; as AJAX calls don't show you ASP.NET error HTML when a request breaks... Firebug showed me.  The result was enlightening:

"A potentially dangerous Request.Form value was detected from the client..."
Interesting.  Do you see the "br"eaking issue here?

That's right... ASP.NET does request validation on all requests by default, to ensure prevention of cross-site scripting (See the MSDN article "How To: Prevent Cross-Site Scripting in ASP.NET" for more explanation.)

We were adding the tags into the HeaderText() calls on the cells in the grid setup on columns where the data in that column was guaranteed shorter than the header text, so we could avoid growing the table unnecessarily wide.

As soon as I removed those tags, it worked like a champ.

So be warned, don't put any HTML tags in your HeaderText calls, or you'll be bitten the same.  I hope this saves someone else several hours of pain.  I know it will save me in the future when I run into other Syncfusion grids in our app that are mysteriously not performing their AJAX calls correctly.  That'll be the first thing I look at.

(And did I mention that Firebug rocks?!)

PLINQO! (No, not the game on Price is Right.)

My friend Tyler introduced me to PLINQO, a killer looking LINQ to SQL ORM data layer, for a side project I'm collaborating with him on.

I'm total newb to it, but I drooled when he gave me a quick crash course on how it works. It's giving me a wonderful opportunity to brush up on the LINQ skills and remember why I love .NET development so much.

I'm excited to see how it plays out for me... if I like it enough, I'll start using it in my own personal projects.

One thing I've been impressed with in the VERY short time I've used it so far, is how easy it is to pick up and run with.

How can you not like this:
public string[] GetStateEmployeeNames( int stateId )
{
string[] stateEmployees = (
from se in this.DataContext.StateEmployee
join e in this.DataContext.Employee on se.EmployeeId equals e.EmployeeId
where se.StateId == stateId
orderby e.Name
select e.Name).ToArray();

return stateEmployees;
}

It's goodness... I can't wait to see what other ease and power PLINQO will offer. Stay tuned...

Ensure XHTML Strict Compliance by Removing Name Attribute from Form tag in ASP.NET

Many of us web developers are trying to be "good citizens" and conform to the higher standards of XHTML in our apps.

By default, ASP.NET will add the name="FormName" attribute to the rendered XHTML.

To force ASP.NET to omit the name attribute, simply add the following tag to the system.web section of your web.config file for your app:

<xhtmlConformance mode="Strict" />

Be warned, however; unfortunately it doesn't seem to make ASP.NET render HyperLinks properly. I have an asp:HyperLink that happens to have an ampersand (&) in the Text and ToolTip properties. The ToolTip properly renders a title="" attribute with the ampersand encoded as &amp; ... but the text between the open and close <a> tags doesn't have the ampersand properly encoded.

The only advice I can give you there is to:
1. Use the word "and" instead of an ampersand
2. Make static "a" tags instead of using the ASP.NET HyperLink object, if you can. If someone knows a smoother/quicker/more elegant solution, please leave a comment with it!

"The breakpoint will not currently be hit" "The source code is different then the original version"

Today, I was debugging an ASP.NET website. I was at a breakpoint when a co-worker called me over to their desk to help with a defect they were trying to reproduce.

I needed to use remote desktop to look at something on my own machine, so I did so. While I was accessing it via remote desktop, my Visual Studio decided to crash.

Aftwerward I started seeing the following on breakpoints I was trying to hit:
"The breakpoint will not currently be hit. The source code is different then the original version"

I thought that a reboot would help, but to no avail.

After talking to another co-worker that had seen it in the past, he informed me that he fixed it by deleting all of the Temporary ASP.NET Files.

Sure enough, it worked like a champ. However, I had to shut down anything that had handles on those files (like the ASP.NET development server, Visual Studio, etc.) before I could complete the delete.

So to fix the problem:

1. Close out Visual Studio and make sure any instances of ASP.NET development server are closed as well.
2. Delete everything from "C:\Windows\Microsoft.NET\Framework\v.2.0.50727\Temporary ASP.NET Files" (where v.2.0.50727 is the version of the .NET Framework your site is running on.)

Hope this helps someone else... it sure helped me.

Error connecting to undo manager of source file "whatever control/page.designer.cs"

I've run into this problem a couple of times where I get an error that states:
Error connecting to undo manager of source file "MyControl.ascx.designer.cs" (I've seen it with an aspx.designer.cs too.)

I don't know what the cause is, but I have a sneaking suspicion that the culprit in both of my cases was merge operations from source control interactions where, for whatever reason, my designer became out-of-sync or something with its ascx/aspx counterpart.

After searching around the net, it seemed the most popular method of correcting the problem was to delete the designer completely, then run the option to convert the project to a Web Application.

That option didn't sit right with me. I searched on.

I found an article by Scott Hanselman that discussed excluding the designer from the project, recompile, re-include, recompile again. That seemed a much more fitting solution to me; but I wondered if it could be even easier. So I tried an experiment.

My experiment consisted of simply opening the designer.cs file, typing a character somewhere in the file, deleting the new character, saving the file and recompiling.

The problem disappeared for me after that. (I will note that I cleaned the solution and rebuilt it prior to trying this, and that may be a required piece of the solution to the problem, but I would try the simple step first, then add in the clean/rebuild after.)

I'm using Visual Studio 2008 SP1. I hope this helps someone else out there.

ASP.NET Development Server Responds with 403 - Forbidden in Firefox

I've been working on an ASP.NET site for a few months that requires Windows Authentication, and it was working fine when running the site in the ASP.NET Development Server and accessing in Firefox.

That is, until today.

Today, it decided to start kicking back Forbidden messages every time I tried to access it. Why would it start doing that to me?

It turns out I had at some point told Firefox to remember the password for the site, then had to change my domain credentials after doing so. Since my saved password didn't match the new password, the site was forced to return a Forbidden. I would hope that Firefox would prompt me for a new password when the authentication failed, but it didn't.

So how do we get back to good in Firefox?
You have to go into the Saved Passwords settings in Firefox and remove the site from the list of passwords to store.

In Firefox 3:
Tools | Options
Click on the "Security" button on the ribbon at the top of the Options dialog

Click the "Saved Passwords..." button in the "Passwords" section of the "Security" tab.
Find the offending site in the "Saved Passwords" dialog and click the "Remove" button.

Click "Close" on the "Saved Passwords" dialog.
Click "OK" on the Options dialog.
Open the site again and Firefox should prompt you for the new credentials.

Hope this helps!

Why We Must Use Classes Instead of Structs for Read/Write DataBinding in C#

Structs are Value Types.
Classes are Reference Types.

When we DataBind in C#, if we're using Value Types... we get copies of those objects instead of pointers to them, for that's how they are passed to the bound control. Therefore, you can't edit the bound control and expect the original objects to be modified. The bound control is only editing the copies and thus we encounter side effects when DataBinding a list or array of value types (like structs.)

I ran into this on a project I was working on where I needed to show a DataGridView for editing attributes. My attribute representation was a struct with a name property and value property... and when I bound a BindingList to the DataGridView, the list would appear... but when I'd edit the values would return to the old values... and when I'd add rows, the values would disappear.

The explanation above explains why. It didn't dawn on me until I started searching for "BindingList structs" and found Bill Wagner's "Of DataBinding and Value Types" (archive.org since the site is no longer available). The title tipped me off because I wasn't thinking about the fact that structs are value types.

Bill's article explains in more eloquent detail than I care to go into here, as I don't feel the need to re-write a well written essay on the topic. I only hope to provide a quick answer for those searching for it, that don't find Bill's article first (and leave myself a quick reference when I forget the next time I try to use a struct...)

He also mentions in his article when it is appropriate to use structs. Thanks for a well-done article, Bill.

So, reminder: use classes instead of structs when you need to do read/write binding. If you're merely databinding for a viewable list... use structs as you like.