evan k. stone :: web development blog

Where's My File? Server.MapPath to the Rescue!

2010-02-01T11:10:00.000-08:00

During the task of trying to serve up dynamic image content from a database, it turned out that in certain circumstances I also needed to read a local image file on the server too.

This was for the case in which no data was found or was missing for some reason -- basically an "Image Not Found" image. The problem is that I had not had to deal with the problem of locating a file in the web application file hierarchy before, strangely enough.

So when I tried to use the File.OpenRead() method, each of the various values for the path I tried didn't work properly and the file could not be found.

Thankfully, I found this post on the ASP.NET forums:

How to read image file ? - ASP.NET Forums

The important piece of information for me was the bit about using Server.MapPath() -- that was the crucial piece of the puzzle I was missing.

So here is what I came up with:

protected byte[] GetImageFromFile(string fileName)
{
 byte[] image = new byte[1];
 image[0] = 0;

 try
 {
  string filePath = 
    Server.MapPath("~/images/" + fileName);

  if (File.Exists(filePath))
  {
   FileStream fs = File.OpenRead(filePath);
   image = new byte[fs.Length];
   fs.Read(image, 0, image.Length);
  }

 }
 catch (Exception ex)
 {
  logger.Error(ex);
 }

 return image;
}

Then I call this method and write it out with Response.BinaryWrite() (shouts out to Derek Pinkerton as well for his good blog post on the subject of Response.BinaryWrite() - it was very helpful in this process as well...)

I could genericize it to retrieve a file from anywhere, for now I YAGNI'ed it since I really was just needing to serve up image files from the image directory. If that changes in the future I can very easily modify it or create a more general method for handling that. A trivial modification.

Page_Load event firing twice

2009-11-24T15:28:00.000-08:00

This has not been a really great week for me and ASP.NET...

I ran into this problem after fixing the other problem:

Page_Load event is firing twice - ExtremeExperts

So with that information, coupled with this information:

Stackoverflow.com - ASP.NET Page.OnLoad executes twice

...and this item from the Microsoft KB:

How to use the AutoEventWireup attribute in an ASP.NET Web Form by using Visual C# .NET

...I was able to solve this double-page-load problem since I was, in fact, wiring up events in a page that had AutoEventWireup set to "true" and the Page_Load was getting fired twice. Awesome.

Anyway, another bullet dodged.

Dynamically Created LinkButtons and UpdatePanel Woes

2009-11-24T14:03:00.000-08:00

Check out my pain as described in this ASP.NET forum post:

Button command not working inside an UpdatePanel - ASP.NET Forums

Totally ridiculous how much work I had to do to get this function working.

ASP FileUpload Controller in AJAX Accordion - Stack Overflow

2009-11-18T12:37:00.000-08:00

When working with ASP.NET, then ASP.NET AJAX, invariably you end up nesting all sorts of wacky controls inside one another.

I had been carefully avoiding putting a FileUploader inside an UpdatePanel since generally it means headaches because the FileUploader security model does not really fit into the AJAX model... maybe someday it will.

At any rate, I ended up with an FileUploader inside an Accordion inside an UpdatePanel, and of course, it stopped working since it needed a full postback, not an AJAX partial postback.

So this post on Stackoverflow.com is probably the most succinct solution to the problem I've seen and it totally makes sense:

ASP FileUpload Controller in AJAX Accordion - Stack Overflow

Here's the code:

<ajaxToolkit:AccordionPane >
 <Header><asp:LinkButton ID="lbtnOption1" runat="server">Option 1</asp:LinkButton></Header>
 <Content>
  <asp:UpdatePanel ID="UpdatePanel1" runat="server">
   <ContentTemplate>
     /* Put HtmlInputFile and upload button here*/
   </ContentTemplate>                  
   <Triggers>
      <asp:PostBackTrigger ControlID="btnUpload" />
   </Triggers></asp:UpdatePanel>                                        
 </Content>
</ajaxToolkit:AccordionPane>

Slumming it with IUI and ASP.NET

2009-10-05T18:20:00.000-07:00

With all the hype surrounding the iPhone, the SDK, and building applications for the App Store (which recently tipped the scale at 2 billion downloads), I'm taking a slightly different angle and am exploring "old-school" iPhone develompent: Web Development.

I was just mulling things over and it seems to me that there still is definitely a market (or rather, a need) for iPhone web applications.

So I'm investigating IUI, since it's relatively "mature" but the thing I'm concerned about is how well it integrates (or doesn't) with ASP.NET. So that's what I'm going to be exploring in the near future.

Big Shout Out for Panic's Coda - Awesome Web Development Tool for Mac OS X

2009-08-14T10:40:00.000-07:00

Over the last few days I've discovered Coda from Panic:

Panic - Coda - One-Window Web Development for Mac OS X

It is a truly awesome tool for doing web development and it does exactly what I want it to:

By default it opens to the file system on the left pane, with the editor on the right

It just works.

It's code sensing (a la IntelliSense) is fun!

Anyway it's definitetly worth checking out.

Notepad++: How to Associate Syntax Coloring for a File Extension

2009-06-17T12:13:00.000-07:00

For the life of me, I could not figure out how to permanently associate the XML syntax coloring for files with a .config extension in Notepad++.

The help did not help, nor did the FAQs.

At any rate, this is how you do it:

Settings Menu --> "Styler Configurator" (which then displays the "Style Configurator" window (note the discrepancy)).
Click on "XML" in the Language list on the far left.
Notice at the bottom there are two text boxes: Default ext and User ext.
Enter config in the User ext text box.
Click Save & Close.
Open a file with .config extension - file should be automatically highlighted.

Here's a suggestion for Notepad++ developers (since it doesn't seem as if they have UX or Interaction Designers on the team)...

Help the user out by doing one of the following:

When an unrecognized file is opened ask what kind of file it is, or
When the user clicks on an entry in the Language menu, save it as the default for files with that extension.

Thanks!

TIP: How To Fix ASP.NET CalendarExtender when used with Blueprint CSS

2009-04-13T15:04:00.001-07:00

I just ran into a bizarre condition where, when using the Blueprint CSS with ASP.NET AJAX Toolkit, the popup calendar produced by the CalendarExtender control has its date numbers pushed out so I only saw about four or five days in each week.

It turns out that this is caused by the padding defined in Blueprint for TD elements are set to 5px. This expands the calendar so only part of it is visible in its containing div.

To fix the problem, I added a DIV called "calendarContainer" around the text box and the CalendarExtender control to "insulate" them:

<div id="calendarContainer">
  <asp:TextBox ID="dateFromTextBox" runat="server"></asp:TextBox>
  <cc1:CalendarExtender ID="dateFromCalendarExtender" runat="server"
    TargetControlID="dateFromTextBox"></cc1:CalendarExtender>
</div>

...and then added the following to my CSS file:

div#calendarContainer table td {
 margin:0px;
 padding:0px; 
}

The calendar dates snapped right back!

Problem solved!

kuler: thank you, adobe...

2009-03-27T12:56:00.000-07:00

Since I'm not a trained designer, it sure is nice that Adobe has created Kuler, which is a community driven collaborative environment for sharing colors and swatches:

kuler

(...you can even access it from within Adobe Illustrator. very cool.)

Colors are definitely one of those areas I have a big weakness, since I never studied color theory. So it's very nice to see the palettes and swatches other folks (i.e. competent designers) have created.

Thanks, Adobe!

ASP.NET Bug: Button.OnClientClick

2009-01-30T11:05:00.000-08:00

I really don't understand this one.

According to the ASP.NET MSDN online documentation for Button.OnClientClick Property (System.Web.UI.WebControls), you use Button.OnClientClick to assign a client-side script (javascript) when the button is clicked (for example if you want to have the button perform some action(s) before submitting, or to short-circuit the click entirely).

However, I couldn't understand why the client-side onclick handler was not getting rendered, no matter what I tried!!!

Then I scrolled down to the bottom and noticed the comment by user contributor "Perley":

"MS has made it so that if you disable the button on the server then the onclick attribute is not even rendered to the client"

Mystery solved.

I had indeed set the button to be disabled in the markup, and it was flat-out not rendering the onclick handler in the HTML.

I fixed the problem by wiring up the onclick event for the button manually using a pageLoad function, but still it was a hassle.

I really think the people who designed, approved, and coded that "feature" should get their head checked, because, seriously... if a button is disabled initially, don't you think it's possible that the button - a user interaction device - might become enabled at some point, and not through server-side intervention???

Developer's Guide - Google AJAX Language API - Google Code

2008-06-09T13:09:00.000-07:00

Over the last few months I've been attempting to learn Portuguese, and, having finally been dismayed by the lack of an API from Babelfish (formerly AltaVista, now Yahoo!), I was pleasantly surprised to see that Google now has a translation service.

I'm really excited about this, since not only do they have a decent translation page, they're also exposing an API:

Developer's Guide - Google AJAX Language API - Google Code

Way to go, Google!

This opens doors for applications, both web and [internet connected] desktop, to perform translations.

They also have the ability to detect the source language, but I'm not sure how useful that would be for me personally, but it's a cool feature nonetheless.

Casting with "as" in C#

2008-04-11T12:57:00.000-07:00

C# provides a couple of methods for casting. One way is the way most familiar to C/C++/Java programmers:


    Foo foo = (Foo)bar;

The second way is through the use of the "as" keyword, which may feel more comfortable to ex-VB programmers (since it also has an "as" keyword):


    IFoo foo = someObject as IFoo;

...and the great advantage of the latter form is that "as" returns null if the object does not support the type (or interface) in question, instead of throwing an exception. This is really handy if you're trying to do invoke a method at runtime and you want to only do it to the object if it supports the interface:


    if (foo != null)
    {
        foo.DoSomethingInterestingNow();
    }

I guess you could also do this with "is" and a cast too:


    if (bar is IFoo)
    {
        foo = (IFoo)bar;
        // or:
        //foo = bar as IFoo;
        foo.DoSomethingInterestingNow();
    }

How to Automatically Generate XML Comments in C# using Visual Studio .NET 2005

2008-04-03T10:29:00.000-07:00

(Since I don't have a desktop software development blog right now I figured I'd better just put this here, since it could apply to C# programming with ASP.NET...)

To automatically generate XML comments in C# using VS.NET 2005, all you have to do is type a triple-whack ("///") in your code before a method definition and the IDE will build out the XML for you.

I accidentally stumbled on this on the same day I was trying to find out how to do it, which doesn't happen too often. I actually found it while nosing around in the VS.NET preferences:

Tools --> Options --> Text Editor --> C# --> Advanced

...which has an "XML Documentation Comments" section and a "Generate XML documentation comments for ///" checkbox.

You really need your miner's helmet for that one! Whew!

JavaScript in Internet Explorer 8

2008-03-12T17:52:00.000-07:00

This sounds like really good news for JavaScript programmers...

John Resig - JavaScript in Internet Explorer 8

(in case you're wondering, John Resig is the developer behind JQuery...)

Setting up Ruby on Rails on Mac OS X with Locomotive and MAMP

2008-03-01T08:24:00.000-08:00

Here's a succinct rundown on how to get ruby on rails running on your mac using locomotive and mamp...

locomotive mamp = ruby : Red91.com

It's a lot easier than the steps on Hivelogic, but the Hivelogic tutorial definitely is a good introduction to setting it up with the command line and is probably more flexible as a result, even if more complex -- especially when you start running into bizzare "Could not find rails (> 0) in any repository" errors, which can be remedied by using these blog posts:

Army of Evil Robots | Could not find rails (> 0) in any repository
Mac OS X 10.4 (Tiger) + RubyGems + Rails

Great Intro Description of Adobe Flex

2008-02-19T21:50:00.000-08:00

I thought this article contained a great description of Adobe Flex, and how it differs from Flash as a development tool...

Get oriented to Flex - Flex 3 Getting Started - BETA - Adobe Learning Resources

YUI Blog: iPhone Performance Research

2008-02-07T11:48:00.000-08:00

Since web development for the iPhone is a hot topic lately, this article on the YUI Blog is very timely and informative...

Performance Research, Part 5: iPhone Cacheability - Making it Stick - Yahoo! User Interface Blog

Here's a brief introduction:

This article, co-written by Wayne Shea, is the fifth in a series of articles describing experiments conducted to learn more about optimizing web page performance

Chris Heilmann: Code tutorials for lazy people with Ajax Code Display

2008-02-07T10:40:00.000-08:00

Perfect! Just for me!

Code tutorials for lazy people with Ajax Code Display

Chris Heilmann: "Five things to do to a script before handing it over to the next developer"

2008-02-07T10:34:00.000-08:00

I thought this was a pretty interesting set of best practices for use when developing in JavaScript in a team environment...

Chris Heilmann's Blog: Five things to do to a script before handing it over to the next developer

Drosera [not] on Windows

2007-11-07T11:23:00.000-08:00

Drosera is a pretty cool debugger for WebKit/Safari (Mac) - at least it's miles beyond what we've had to work with in the past...

Unfortunately, according to the official Drosera wiki page, it's not available for the Windows version of WebKit/Safari (yet):

Drosera on Windows
Drosera is currently not available on Windows. Much of Drosera is written in JavaScript and should require very little modifications to run on Windows. The Cocoa application wrapper is not portable will need to be rewritten using native Windows APIs. Hop onto our irc channel if you're interested in porting Drosera to Windows.

So hopefully some enterprising individuals will take the initiative and do the port.

Ajaxian - Companion.JS: IE Debugging

2007-10-23T10:21:00.000-07:00

This could really come in handy, since debugging with Visual Studio or the MS Script editor can really be a pain sometimes:

Ajaxian - Companion.JS: IE Debugging, now supports console.log

Aptana IDE - with iPhone support!

2007-10-02T14:45:00.000-07:00

Just found out about this plugin for Eclipse for doing JavaScript, HTML (and iPhone development!):

Aptana IDE is a free, open-source, cross-platform, JavaScript-focused editor and development environment for building Ajax applications. It features code assist on JavaScript, HTML, and CSS languages, FTP/SFTP support and a JavaScript debugger to troubleshoot your code.

Aptana: The Web IDE

You can also download a plugin for assisting with iPhone development:

Apple iPhone Support

The Apple iPhone Development Plugin (beta) enables the Aptana IDE to increase your iPhone development productivity.

Important Note...

I wanted to install Aptana over my existing eclipse installation (which you can), and I found that while installing it in this fashion it could generate exceptions if you installed it to the wrong directory.

I was unknowingly installing to the directory in which my MyEclipse plugin was installed, and it really didn't like that.

So after changing the installation directory to "c:\tools\aptana", the installation seems to have worked just fine. After installing the core IDE, then you can install the iPhone plugin directly from its start page.

iPhone Simulation on OS X with Marketcircle's iPhoney

2007-10-01T15:07:00.000-07:00

A colleague just sent me a link to this product, since he heard that I wanted to work on a project for the iPhone, even though I do not currently possess one:

Marketcircle: iPhoney

Free, so it's worth a try I guess!

Pro JavaScript Design Patterns

2007-09-06T11:10:00.000-07:00

I'm really interested in this book that's now available for preorder on Amazon...

Amazon.com: Pro JavaScript Design Patterns

I think this is something that we've been missing and is really crucial to have it codified. I've been visting Dustin Diaz' site (http://www.dustindiaz.com) for some time, and he has some really useful javascript tips, advice, and patterns... looking forward to the book!

DotNetNuke - Fixing a Strange Blog Module Error

2007-08-02T15:10:00.000-07:00

It always makes me nervous when I have to crack open the source code for someone else's component, but that's pretty much what you have to do to get the DNN blog module to work correctly for registered users (this is evidently not a problem for admin-level users):

DotNetNuke Blogs - The server tag is not well formed, oh
my!
http://www.dotnetnuke.com/Community/Blogs/tabid/825/EntryID/1496/Default.aspx

...turns out having a unicode accented "e" character is probably not a good thing. ;)

DotNetNuke - How to set the container width

2007-08-02T15:01:00.000-07:00

Lately I was having an issue with a particular skin I have been using for a DotNetNuke-based site I'm working on- namely how to get the main content of the page to fill the whole page instead of constraining to 750 pixels or so.

Thankfully, I found the following post describing how to accomplish the adjustment, which ultimately was pretty straigtforward, though I wasn't thrilled with changing the skin's core CSS:

http://www.dotnetnuke.com/Community/Forums/tabid/795/forumid/48/threadid/127044/scope/posts/Default.aspx

Seems like this should have been a setting somewhere. Oh well...