All posts by Steven

Neat, Quick Debug to Console Output

A very easy wayt to get Debug output for your debugging purposes:

 


  • Add the ‘System.Diagnostics’ using statement to the class.
  • use the ‘Debug.WriteLine(“Batman is totally kick butt”);’ syntax to send debug signals to any listeners
  • Add a Debug listener to your tester app; 

[code:c#]TextWriterTraceListener myWriter = new TextWriterTraceListener(System.Console.Out);
Debug.Listeners.Add(myWriter);
[/code]

Enjoy!

Using, IDisposable and Such

I was messing with a PDF generating class (PDFSharp, an excellent free .NET PDF Toolkit for creating PDF’s) and had to create a class that will load up some images (logos, watermarks, etc.) and then use those for the PDF. The problem is that these type objects are GDI+ type objects and are unmanaged objects. This became a problem because the logos I created during the PDF generation would remain in an opended state by the PDF generation class. This prevented me from deleting the logo file and just really pissed me off.

So IDisposable to the rescue. This allows me to manually manage the disposal of the unmanaged objects and then I could implement the PDF generation class in a using and viola! I was able to delete the image file with no issues.

Here and Here are a couple of great websites with notes and hints about implementing the IDisposable interface in C#. 

The only part that got me is the Finalizer and realizing that the Finalizer is called when the object is destructed by the GC. This is not safe to assume this is at the same time that the object is being disposed (end of a Using statement). So that is why some of the examples you find will have a Dispose(false) to a Dispose method. This prevents the managed objects from being collected in the destructor as the order is unpredictable. If that makes sense to you, great!

Here is a very simple class implementing the IDisposable interface;

[code:c#]
public class PDFMaker : IDisposable 
{
    // some fields that require cleanup
    private SafeHandle handle;
    // this is the Handle to the GDI+ object     
    private bool disposed = false; 
    // to detect redundant calls      
    public PDFMaker()     
    {         
        this.handle = /*…*/;
        // Cheezy example     
    }
    public void MakePDF()  
    {   
        // Do something cool here and make a PDF    
    }
    protected virtual void Dispose(bool disposing)
    {
        if (!disposed)
        {
            if (disposing)
            {
                if (handle != null)
                    handle.Dispose();
            }
            disposed = true;
        }
    }
    public void Dispose()
    {
        Dispose(true);
    }
}
[/code]

Enjoy!

A GUID of by any other name?

I was mokeying around today with GUID's and had a time with the durn things returning '00000000-0000-0000-0000-000000000000' as the GUID value.

The code I was using was;

[code:c#]Guid g = new Guid();[/code]

Then that would create a new Guid and set its value to '00000000-0000-0000-0000-000000000000'. Blah.

So instead I find this;

[code:c#]Guid g = Guid.NewGuid();[/code]

This generates a proper Guid value (was '1b6d4d3c-0e6e-4967-a389-281c4fb435d3' in this case).

Geez. You figure that would do what you want, someone smarter than I am about Guid's can leave a comment to clear up the mystery.

Enjoy!

 

Subversion (svn) MonoDevelop on Ubuntu Hardy Heron (8.04.1)

So I tried to get the MonoDevelop release in Subversion to work with Ubuntu Hardy Heron (8.04.1) and had a heck of a time getting it to work.

Finally after much chatting on the IRC channel I did these steps;

  1. Setup badgerports as a repository
  2. Do the the 'ol 'sudo aptitude update && aptitude upgrade' 
  3. Run this; 'sudo apt-get install build-essential mono-mcs mono-gmcs mon-devel libmono-dev lipango1.0-dev libgtk2.0-dev libgtksourceview2.0-cil libgecko2.0-cil monodoc libmono-system-runtime2.0-cil gettext'
  4. Ensure you have 1.9 mono-gmcs installed; 'gmcs –version'
  5. Ensure you have 1.9 mono installed; 'mono –version'
  6. Follow the Subversion setup on the Monodevelop website, all should work now

Enjoy!

 

VirtualBox Clone Not Booting Windows XP

I was playing around with the new 1.6.2 Sun branded VirtualBox and thought I would clone one of my existing VDI's to a new one and then setup a new VM to use that VDI to play with.

So the first thing I did was clone the VDI using the cmd tool that comes with VirtualBox:


C:\Program Files\Sun\xVM VirtualBox\VBoxManage.exe C:\users\steven\.virtualbox\vdi\foo.vdi C:\users\steven\.virtualbox\vdi\bar.vdi

Nifty. Worked like a charm. Then you just go into the VirtualBox Virtual Disk Manager and add the newly cloned bar.vdi and then setup a new VM as usual to use that VDI.

But then of course it didnt want to boot Windows, just a series of lovely BSOD and reboots. Joy.

I trolled around on the forums and found that Innotek (or I guess Sun now) changed the default IDE controller from  PIIX3 to PIIX4 and this change seems to make Windows XP very unhappy. Go into the VM under the Advanced tab change from 'PIIX4' to 'PIIX3'. Now it boots. 

My only real compliant with VirtualBox is, well ok my only two complaints are; 1. Virtual Networking is a real PITA and 2. Why not have a UI for all the awesome options found in the
VBoxManager.exe utility. Ah hell the price is awesome, and I get great
USB support (boo! no USB device support for Virtual PC) and I dont have to download a 125MB download and register (boo! VMWARE).

Enjoy!

Simple Char

Ok so I evidently am not the sharpest knife in the drawer. I was trying to figure out how in the heck you set create and set a char variable.

Example:

[code:c#]char c = new char("s".ToCharArray[0]);[/code]

Yea I know now its as simple as using the single tick to specify the char literal;

[code:c#]char c = new char('s');[/code]

Good grief. Ah well, live and learn.

Reading Gmail with Sup

I wanted a simple mail client that would handle all the mail I receive from various accounts and ran across Sup. Impressivly simple and very nicely done in a console application.

Here are the steps I took to get Sup both reading mail in my Gmail account and sending mail out via my Gmail account on my Arch workstation;

  • Installed  Yaourt
  • Installed Ruby and Rubygems via Yaourt
    • yaourt -Sy ruby rubygems
  • Installed VI via Yaourt
    • yaourt -Sy vim vim-colorstamplerpack
  • Installed sSMTP via Yaort
    • yaourt -Sy ssmtp
  • Setup sSMTP following this Wiki Entry
  • Installed Chronic (a date parser, dependency of Sup) via the Ruby Gems tool
    • sudo gem install chronic
  • Downloaded the latest Tarball of Sup, unpacked it into /tmp and installed it via the Gems
    • sudo gem install sup -y
  • My ~/.sup/sources.yaml file looks like this;
  • 	steven ~/.sup $  cat sources.yaml
    	---
    	- !masanjin.net,2006-10-01/Redwood/IMAP
    	uri: imaps://imap.gmail.com:993
    	username: myaccount@gmail.com
    	password: mygmailpassword
    	cur_offset: 12117761440000842
    	usual: true
    	archived: false
    	id: 1
    	labels:
    	- gmail
    	- !masanjin.net,2006-10-01/Redwood/SentLoader
    	cur_offset: 555
    	- !masanjin.net,2006-10-01/Redwood/DraftLoader
    	cur_offset: 0
    	

I found this guide very helpful for Sup

Enjoy!

ps; Man does posting from this HTML interface suck rocks. Gotta get some sorta MS Live Writer going. 

Flood of log messages about USB over-current

So on my Notebook I noticed I was getting a flood of these frickin' messages;

hub 1-0:1.0: over-current change on port 1

I mean like 5 a second, over and over and … and …

Googl'ed this madness and found no good answer, so I thought I would take an extreme approach and just have Syslog-ng just not log it!

Add this to your destination collection in /etc/syslog-ng.conf;


destination nowhere { file("/dev/null"); };

Then add this to the filter section;


filter f_usb_occ { match("over-current change"); };

Then finally add this to the log section;


log { source(src); filter(f_usb_occ); destination(nowhere); flags(final); );

Restart Syslog-ng and viola! no more logging of that irrating message. woot!

Enjoy!