Wednesday 13 June 2012

Please support the campaign to save lennox

While I know my readership isn't high I wanted to share the following in the hope that if even one of you signs the petition then we can help push up the numbers to the point where we cannot be ignored.

If you care about animals and are as gobsmacked as me by the groundless adherance to the letter of the unjust Breed Specific Legislation in Belfast then please sign the petition to save lennox - condemned to be destroyed for basically looking like a dog that wouldn't necessarily be dangerous anyway - for more - please spread the word and try and get this ruling overturned

Tuesday 12 June 2012

Microsoft conferences online

As this has come up a few times lately I just wanted to post some links up to the online archives for the various Microsoft conferences. I have to say the fact that you can get at these archives permanently, as well as when the conferences are still running is just one of the reasons I love MS's attitude to developer relationships.

The conferences do have different focuses, but these days you will normally find something on most subjects at any of the conferences.

Teched (which is running now, at the time I write this post) - this one is normally quite heavy on IT, but with some interesting dev pieces in there
Build - this one is for the devs, though quite a bit on design/UI as well. This first ran in 2011 to introduce us to Windows 8 / Visual Studio 2012 -

The Professional Developer Conference (PDC) - the key's in the name - for devs mainly, was the forerunner to Build - Archives from 1991 to 2010 are at

MIX - mainly for designers tho with some dev in there aswell - archives from 2006 to 2011 are at

These are all worth a look through - there are 1000s of hours of the best insight to working with the MS platforms you could possibly hope for.


Sunday 26 February 2012

Accessing Printer Status using WinSpool in C#


After help from ambience I’ve managed to get the code working to access accurate printer status by using DllImport to access Winspool.drv (as opposed to using WMI, which had very mixed results).

There are 3 key functions you need to be aware of:

  • OpenPrinter
  • GetPrinter
  • ClosePrinter

The GetPrinter function is the one that does the real work we are interested in – accessing the PrinterInfo2 structure that gives you all the information you could possibly want on your named printer – driver, status, configuration, etc

Once you have the PrinterInfo2 you can than use bitwise operators along with known constants to find out the current status of the printer. One thing to note is that to detect whether a printer is marked as offline rather than physically offline you need to check the Attributes rather than Status – I’ll put a followup post shortly with details of a Helper class round the PrinterInfo2 status.

Here’s the code to help you out if, like me you need to get accurate printer info in C#:

//Code written by Mark Middlemist - @delradie 
//Made available at
//Interop details from
using System;
using System.Runtime.InteropServices;

namespace DelradiesDev.PrinterStatus
  public class WinSpoolPrinterInfo
    [DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
    public static extern int OpenPrinter(string pPrinterName, out IntPtr phPrinter, ref PRINTER_DEFAULTS pDefault);
    [DllImport("winspool.drv", SetLastError = true, CharSet = CharSet.Auto)]
    public static extern bool GetPrinter(IntPtr hPrinter, Int32 dwLevel, IntPtr pPrinter, Int32 dwBuf, out Int32 dwNeeded);
    [DllImport("winspool.drv", SetLastError = true)]
    public static extern int ClosePrinter(IntPtr hPrinter);
    public struct PRINTER_DEFAULTS
      public IntPtr pDatatype;
      public IntPtr pDevMode;
      public int DesiredAccess;
    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    public struct PRINTER_INFO_2
      public string pServerName;      
      public string pPrinterName;
      public string pShareName;
      public string pPortName;
      public string pDriverName;
      public string pComment;
      public string pLocation;
      public IntPtr pDevMode;
      public string pSepFile;
      public string pPrintProcessor;
      public string pDatatype;
      public string pParameters;
      public IntPtr pSecurityDescriptor;
      public uint Attributes;
      public uint Priority;
      public uint DefaultPriority;
      public uint StartTime;
      public uint UntilTime;
      public uint Status;
      public uint cJobs;
      public uint AveragePPM;
    public PRINTER_INFO_2? GetPrinterInfo(String printerName)
      IntPtr pHandle;      
      PRINTER_DEFAULTS defaults = new PRINTER_DEFAULTS();      
      PRINTER_INFO_2? Info2 = null;
      OpenPrinter(printerName, out pHandle, ref defaults);
      Int32 cbNeeded = 0;
      bool bRet = GetPrinter(pHandle, 2, IntPtr.Zero, 0, out cbNeeded);
      if (cbNeeded > 0)
        IntPtr pAddr = Marshal.AllocHGlobal((int)cbNeeded);
        bRet = GetPrinter(pHandle, 2, pAddr, cbNeeded, out cbNeeded);
        if (bRet)        
          Info2 = (PRINTER_INFO_2)Marshal.PtrToStructure(pAddr, typeof(PRINTER_INFO_2));
      return Info2;

Thursday 23 February 2012

Rebinding bug in WinForms ListBox when SelectionMode = None

Just a quick post to help out anyone who hits the same bug I have.

It appears that there are a couple of issues with WinForms ListBoxes when the SelectionMode is None (certainly in .net 2).

One that is pretty well documented is that if your SelectionMode is None then you can get problems on closing the form (

One I've just hit on is that if you rebind/refresh a listbox's contents by changing the datasource then the list is cleared and left blank

The workaround is very simple (based on the one from Connect) - before manipulating the DataSource property on the ListBox change the SelectionMode to one of the other values, do your work, then change it back to None

Hope this helps