SyntaxHighlighter

Thursday, 25 October 2012

HttpContext.Current.Session is null

Had a funny one with an ASP.NET 4.0 C# project I am working on. I moved my session handling into a class to keep things tidy. I started getting the old reference to a null object error when trying to access a session variable.

This initially confused me a little as I was already doing an if (context.Session["myvar"] == null) on it. I then realised that it was the Session object itself that was null. I did a lot of hunting around on Google - and there are hundreds of responses (HttpContext.Current.Session is null). None of them were working for me.

I had checked that sessions were enabled and that the Session_Start event was firing in Global.asax.cs. The most useful article I came across was this one on stackoverflow.

My session handling class was using private static HttpContext context = HttpContext.Current; so that I had a shorthand to the Session object (context.Session). I swapped out the shorthand to use the full path to it (HttpContext.Current.Session) and we were off - all working!

Friday, 12 October 2012

How to Play MP4 Files on Your Xbox 360 - Part 2

Following on from my original article of playing MP4 files on your Xbox 360, I have finally found a conversion tool that works well for me, if changing the extension to avi doesn't work.

I am using XMedia Recode. It's pretty straight forward:

  1. Drag the file(s) into the application that you want to be converted
  2. Make sure you have the settings, as shown below, selected
  3. Click the file, that was dragged in, and click Add Job
  4. Click the Jobs tab to see the file(s) all listed ready to go
  5. Click the Encode button

Once the conversion has completed (the speed of this is dependent on the processing power of your PC), change the file extension from mp4 to avi. Happy viewing!

JavaScript Password Generator and Encryption

I'm an avid user of Passpack and while I was killing 10 minutes, I was bouncing round their site and came across this sweet JavaScript Password and Encryption number.

It gives us AES 256-bit encryption (among others) and simple and complex password generation.

Good work Passpack, I can see it coming in quite handy :)

Thursday, 11 October 2012

SQLCE: Large SQL Statements

Been dabbling quite a lot recently with SQLCE on Windows mobile devices. I came across something that was a little bizarre with a very large statement that I was executing.

I was performing a DELETE with a WHERE clause using a NOT IN. The NOT IN had approximately 1200 IDs in it. Very cunningly, each time it executed, the device hung with no exceptions. Great!

I haven't been able to find any evidence of issues with executing large statements like this, so I resorted to adding the IDs to a table and then modifying the WHERE clause to use NOT IN (SELECT [MyID] FROM [MyTable]).

This took way too long to run! So I changed it to use a NOT EXISTS instead - what a difference, took less than 1 second rather than the 5 or 6 seconds when using NOT IN!

Original:
DELETE FROM [MyTable]
WHERE [MyID]  NOT IN (1, 2, 3, 4, ...1200)

Revised:
DELETE FROM [MyTable]
WHERE [MyID]  NOT EXISTS (SELECT * FROM [MyIDTable] WHERE [MyTable].[MyID] = [MyIDTable].[MyID])

Collapse and Expand All Regions Macro for Visual Studio

I use regions really quite extensively in my .NET projects and did a hunt around for a sneaky Visual Studio macro that would collapse all my regions after I have finished with the file. I came across this article on David Yack's blog that demonstrates some keyboard shortcuts to use. Further down in the article a contributor called Dry put a comment on that was the macro I was after :)

The macro posted worked fine in Visual Studio 2005 but when I put it into 2010 the collapse function didn't stop looping. So I did a little pimp to it and all good - works in 2010 now.

I hope David and Dry don't mind, but I have posted the code here too in case it becomes unavailable...

Sub ExpandAllRegions()
 DTE.SuppressUI = True

 Dim objSelection As TextSelection
 objSelection = DTE.ActiveDocument.Selection

 objSelection.StartOfDocument()

 Do While objSelection.FindText( _
  "#Region", _
  vsFindOptions.vsFindOptionsMatchInHiddenText _
 )
  objSelection.WordRight()
 Loop

 DTE.ActiveDocument.Selection().StartOfDocument()
 DTE.SuppressUI = False
End Sub

Sub CollapseAllRegions()
 ExpandAllRegions()

 Dim objSelection As TextSelection
 objSelection = DTE.ActiveDocument.Selection

 objSelection.EndOfDocument()

 Do While objSelection.FindText( _
  "#Region", vsFindOptions.vsFindOptionsBackwards _
 )
  objSelection.StartOfLine( _
   vsStartOfLineOptions.vsStartOfLineOptionsFirstColumn _
  )
  DTE.ExecuteCommand("Edit.ToggleOutliningExpansion")

  objSelection.LineUp()
 Loop

 DTE.ActiveDocument.Selection.StartOfDocument()
End Sub

You could of course now tie the collapse region function into the EnvironmentEvents module and make it automatically collapse all regions when a document closes. Play about with the DocumentEvents_DocumentClosing(ByVal Document As EnvDTE.Document) Handles DocumentEvents.DocumentClosing event. May want to limit it to cs and vb files only...