Rick Strahl's Web Log

Recent Weblog Posts

No Preview Images in File Open Dialogs on Windows 7
Today @ 1:55 pm

I ran into a problem with a File Open dialog in Silverlight (but this applies to any Windows File Open Dialogs) where I could not get image previews to work. It turns out this setting is controlled by Explorer Customization settings which is a pain to figure out while tracking down the issue.

.NET WebRequest.PreAuthenticate – not quite what it sounds like
February 18, 2010 @ 1:38 pm

On a few occasions I've dealt with Web Services that use - yuk - Basic Authentication and require pre-authentication on the very first request to the server with the server first sending a challenge. This is unusal for HTTP authentication which typically requires a challenge first and then a response with the auth information in the header. The latter approach is what the .NET client components produce by default. PreAuthenticate unfortunately is not quite true to its name and in order to provide true pre-authentication on the first request manual header manipulation is required.

3 comments

jQuery 1.4 Opacity and IE Filters
January 25, 2010 @ 12:42 am

Ran into a small compatibility issue with jQuery 1.4 where the $.css("opacity") function overwrites existing IE filter settings rather than additively applying them which has caused me a few problems with some components that heavily rely on opacity as well as a couple of other IE filters.

3 comments

HttpContext.Items and Server.Transfer/Execute
January 20, 2010 @ 4:32 pm

I got bitten by a the fact that the Context.Items collection stays active throughout the ENTIRE lifetime of an ASP.NET request including Server.Transfer and Execute calls. In certain situations this can cause big problems if you expect the items to be unique for the specific page/component request.

1 comment

Rendering ASP.NET Script References into the Html Header
January 02, 2010 @ 3:26 am

ASP.NET natively supports script embedding only into the body of the HTML document which is limited in many ways if you need more control over how scripts load under program control. In this post I'll show one of my components that allows embedding scripts and script references in the header of the document as well as many useful script embedding features for ASP.NET.

8 comments

LINQ to SQL and missing Many to Many EntityRefs
December 24, 2009 @ 2:05 am

LINQ to SQL expects every table to be mapped to have primary keys which is reasonable. However, today I ran into a problem with an existing database and a many to many relationship which did not have a Pk in the link table. The model and underlying XML seemed to map this just fine, however, the actual generated code did not approve of this arrangement.

10 comments

Making Sense of ASP.NET Paths
December 21, 2009 @ 1:20 am

ASP.NET includes a plethora of functions and utilities to retrieve information about the current requests and paths in general. So much so that it's often hard to remember exactly which path property or method you are actually looking for. This update to an old and very popular post from this blog summarizes many of the paths and path related operations that are available in ASP.NET.

26 comments

SmtpClient and Locked File Attachments
December 18, 2009 @ 3:00 pm

Ran into an easily overlooked problem a few days ago where SmtpClient messages with attachments would keep the attached files locked on the local machine. Email would send fine with attachments but the local files remain locked after sending. It's easy to miss as the files are locked for writing only so subsequent read operations actually work, but the file is still locked. The solution is easy enough by applying a .Dispose() in the right spot, but nonetheless unexpected.

9 comments

A free standing ASP.NET Pager Web Control
December 14, 2009 @ 12:15 am

Although there's decent Pager support in ASP.NET controls the way paging works is inconsistent and not very generic. After a recent experience of creating a small pager component for MVC I decided having a generic non-data or control dependent Pager WebControl would be useful. In this post I cover a custom Pager control implementation that addresses some of the shortcomings with the stock paging functionality for me.

17 comments

Visual Studio 2010 Beta 2 Startup Failures
December 05, 2009 @ 6:25 pm

I’ve been working with VS 2010 for a while now and while it works Ok most of the time it seems the environment is very, very fragile when it comes to crashes and installed packages. Specifically I’ve been working just fine for days, then when VS 2010 crashes it will not start. Instead I get the good old Application cannot start dialog: Other failures I’ve seen bring forth other just as useful...

7 comments

DevConnections Slides and Samples Posted
November 18, 2009 @ 4:54 am

I've posted my slides and samples from my 3 DevConnections sessions for you to download and check out.

8 comments

Capturing and Transforming ASP.NET Output with Response.Filter
November 13, 2009 @ 9:47 am

Capturing ASP.NET response output can be done in a variety of ways. In this post I'll discuss how you can use a Response.Filter to capture output and transform it using a simple class that provides event hooks to make it easy to capture output.

11 comments

$.fadeTo/fadeOut() operations on Table Rows in IE fail
November 09, 2009 @ 12:20 am

There's a rather sneaky bug in jQuery and Internet Explorer that causes jQuery's various fade methods like fadeIn/fadeOut/fadeTo to not work with table elements in any version of IE. The fade behavior doesn't have any effect on tables, rows, headers, but luckily the end result - a removed or visible element still works. Only the fade effect seems to go missing in action.

10 comments

ClientIDMode in ASP.NET 4.0
November 07, 2009 @ 3:58 pm

The new ClientIDMode in ASP.NET 4.0 is one of my most anticipated features to reduce the naming clutter that ASP.NET naming container naming has traditionally introduced into page. In this post I describe the ClientIDMode behavior and the various ways of how you can control ClientID generation with ASP.NET 4.0

17 comments

Ambiguous References in DefaultWsdlHelpGenerator.aspx
November 02, 2009 @ 5:52 pm

Ran into an odd problem today where the default ASMX Web Service help page was blowing up with DataBinding errors due to ambiguous class names. Turns out that a custom control with the same name as a System component and a static method call resulted in ambigous reference errors.

4 comments

No JavaScript IntelliSense in VS 2010 Beta 2? Reset your Settings
October 22, 2009 @ 2:52 pm

When I installed Visual Studio 2010 a couple of days ago I was really disappointed to see that Intellisense failed to work completely in the new install. No workey in .js files, or ASPX pages inside of script blocks. After some back and forth with folks on the ASPInsiders list and the product teams it looks like there is an issue somewhere with the default settings that get set when Visual Studio...

14 comments

A generic way to find ASP.NET ClientIDs with jQuery
October 15, 2009 @ 2:04 am

ASP.NET ClientIDs and NamingContainer naming are a nuisance when working with jQuery as these long IDs complicate finding elements on the page. In this post I show a very simple way to retrieve munged ClientIDs by just their ID names with a small helper function that still returns the jQuery wrapped set.

29 comments

LINQ to SQL, Lazy Loading and Prefetching
October 12, 2009 @ 2:56 am

Lazy loading in an ORM can be really useful or a royal pain if you walk through a lot of data. LINQ to SQL uses lazy loading of related entities and entity sets but there are a couple of ways that allow you to do eager loading instead. Both require some extra effort and foresight.

10 comments

Application that won’t Pin to Taskbar in Windows 7
October 08, 2009 @ 2:02 am

I've run into a dead end with an application of mine that won't pin to the Windows 7 taskbar. I've tried a number of different settings but I just cannot get the app to show the Pin to taskbar (or any othe of the taskbar context options) to work.

31 comments

Fun with Func<T,TResult> Delegates, Events and Async Operations
October 05, 2009 @ 1:38 am

Delegates are powerful for event handling, highly useful in LINQ and a core requirement for async operations. Func makes using delegate based logic a lot easier by providing a generic implemenation that in many cases allows you to skip creation of a separate delegate and instead just point at the Func definition which can be a big timesaver and a nice way to remove delegate defintions from your namespaces.

14 comments

Lookbehind in Regex searches
October 03, 2009 @ 2:03 am

Regex's more esoteric features are easy to miss as they make sense to me only in a context that applies to my work. I've certainly read about lookahead and lookbehind before but until I needed it today and was pointed to look at this functionality in the Regex engine it just didn't sink in. Lookbehind allows matching or not matching of a string before the the string you are interested in. It effectively allows you to look for values that don't have x before another match which is actually quite common.

8 comments

Debugger Visualizers not working in ASP.NET Medium Trust
September 24, 2009 @ 12:48 am

Debugger visualizers are quite useful for looking at common content while in the middle of debugging your application. However I've run into a number of problems with the debugger visualizer not popping up in ASP.NET applications due to the security environment. Turns out you need full trust in order to use debugger visualizers in ASP.NET applications.

2 comments

Integrating OpenID in an ASP.NET MVC Application using DotNetOpenAuth
September 17, 2009 @ 9:15 pm

OpenId is getting more popular and with it requests to integrate it into Web sites as a user authentication mechanism. In this post I'll discuss the OpenId integration on CodePaste.net in an ASP.NET MVC application disuccing both high level OpenId concepts, the process and the code implementation.

29 comments

Making jQuery calls to WCF/ASMX with a ServiceProxy Client
September 15, 2009 @ 8:31 pm

This post revisits the WCF/ASMX ServiceProxy that can be used to make native jQuery calls to ASMX and WCF AJAX services. The component is self contained and provides JSON conversions including dates, as well as a simple class interface for simple one line service calls and consistent error trapping. This is an update that handles native JSON parsers. Includes examples and a detailed walk through on how it works.

16 comments

jQuery UI Datepicker and z-Index
September 12, 2009 @ 8:12 pm

The jQuery UI datepicker is a nice and easy to use datepicker control but if you're using it with other components that use absolute positioning you might run into issues with z-Index precendence. Here's a discussion of the problem and a couple of easy solutions around it.

14 comments

Implementing a jQuery-Datepicker ASP.NET Control
September 10, 2009 @ 4:33 pm

Updated the jQueryDatePicker control from an old version of Mark Grabansiki's jQuery calendar to the latest version of jQuery.ui. This is an easy to use wrapper around the control to make it easy to drop the control onto a page with minimal configuration fuss and provide POST back functionality on the inline behavior.

13 comments

Get and Set Querystring Values in JavaScript
September 07, 2009 @ 2:12 am

Reading and writing query string values is often useful in Javascript code especially when dealing with client side initiatiated paging, sorting and ordering operations. If you need to modify the query string from the client before submitting the page it's nice to have a couple of small routines to do this easily. This short post demonstrates the setUrlEncodedKey and getUrlEncodedKey that do just that.

8 comments

Odd/Even Looping in ASP.NET MVC
August 31, 2009 @ 8:54 pm

Creating lists that have alternating display characteristics for alternating content are common and in MVC you have to do a little bit more work to make this happen. Here's an easy way to represent the expression using a boolean variable.

17 comments

Getting and setting max zIndex with jQuery
August 31, 2009 @ 12:14 am

Finding the largest zOrder is a useful feature if you are building applications that use pop up windows, use modal dialogs or otherwise allow dragging and dropping of content around a page. Here's a small jQuery plug-in that makes it easy to find the highest zOrder or assign a new higher zOrder to a jQuery selected element(s).

9 comments

Speaking at the Portland Area .NET User Group on Tuesday Sept 1st
August 27, 2009 @ 9:49 pm

I’ll be speaking at the PADNUG meeting next week in Portland at the Microsoft office. Rich Hubbins asked me to present on jQuery again as I did last year. A lot has changed in the last year and when I gave the last presentation jQuery was just starting to get some attention in the .NET world. By now many more people have been using jQuery for a while so this talk likely will hit a different...

FireFox Slow Startup: Watch out for Browser Highlighter Plugin
August 27, 2009 @ 1:35 pm

If your FireFox instance is starting up VERY slowly be sure to check whether you have the Browser Highlighter plugin installed. This Skype installed plug-in apparently has some startup problems that causes FireFox to hang for 15-20 seconds. Uninstall!

24 comments

On the Fly DropDown Editing with jQuery
August 24, 2009 @ 2:04 am

One neat feature I've been using in HTML forms recently is to use dynamic pop up drop down lists for editing of list content. The idea is that you have plain text or link labels that when edited are turned into drop-downs for making selections from, which provides a nice interactive effect while editing document content. Here's an example that demonstrates how to dynamically create a drop down, load it up with data and display results using jQuery, MVC and the West Wind Web Toolkit.

8 comments

Windows 7 and a Quick Launch Toolbar
August 22, 2009 @ 12:37 pm

I installed Windows 7 this week after my Vista installation finally started going really whacky while I was in Europe. All things considered Vista has been good – the previous install lasted nearly 2 1/2 years without a repave which is more than any OS I’ve had ever had installed before. The Windows 7 install went fairly smooth for me – no install problems although I screwed myself royally doing...

25 comments

Generic Types and Inheritance
August 18, 2009 @ 11:20 am

Although I use Generics extensively, every once in a while it still throws me for a loop when dealing with complex generic parameters and inheritance. In this post I talk about a compilation error I ran into when trying to inherit a generic type including its generic parameters and a way to get around this particular issue.

5 comments

Simplistic Object Copying in .NET
August 04, 2009 @ 8:04 am

Copying object data between instances of objects is something that needs to be done quite frequently yet there are few tools that perform this task well. Here is an admittedly simplistic routine that I nevertheless find useful in many situations.

18 comments

WebResource access in ASP.NET MVC
July 30, 2009 @ 3:21 am

WebResources are useful when building more complex components. In MVC ASPX Views you can still access the ClientScript object to retrieve ResourceUrls, but outside of the ASPX view there's no easy access to the ResourceUrl. This post describes how grab resource urls in a couple of different ways.

15 comments