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  • Reasons to Use a Work Order Software System

    Keeping track of the bottom line has never been more critical than in these trying economic times. That';s why many companies are choosing to use a work order system to better keep track of jobs and m... [Author: Belinda Verducci - Computers and Internet - June 05, 2010]

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  • Windows Backup fails with 0x80070002: "The system cannot find the file specified"

    - by James Johnston
    Windows 7 Backup is failing. When backing up even a single insignificant directory (e.g. I chose only the empty "Contacts" directory, leaving all other directories unchecked), I get this error within a few seconds and the backup fails. If I uncheck all files/directories, and just do the system image - then the system image is backed up OK without issue. Backup destination is an external USB hard drive. Steps to reproduce and subsequent failure: Set up backup to go to external hard drive. Don't back up system image. Back up "Contacts" directory only for my profile. Start backup. Immediately view the status of the backup, it stays on "Creating a shadow copy..." for a few seconds, and then the backup fails. Click Options button, and it says "Check your backup / The system cannot find the file specified." - with options to "Try to run backup again" or "Change backup settings". If I click "Show Details", then it says: Backup time: 4/12/2012 04:38 Backup location: My Book (D:) Error code: 0x80070002 An examination of the Event Log shows nothing useful beyond the following: Log Name: Application Source: Windows Backup Date: 4/12/2012 04:38:44 Event ID: 4104 Task Category: None Level: Error Keywords: Classic User: N/A Computer: JTJLaptop Description: The backup was not successful. The error is: The system cannot find the file specified. (0x80070002). Event Xml: <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="Windows Backup" /> <EventID Qualifiers="0">4104</EventID> <Level>2</Level> <Task>0</Task> <Keywords>0x80000000000000</Keywords> <TimeCreated SystemTime="2012-04-12T04:38:44.000000000Z" /> <EventRecordID>23979</EventRecordID> <Channel>Application</Channel> <Computer>JTJLaptop</Computer> <Security /> </System> <EventData> <Data>The system cannot find the file specified. (0x80070002)</Data> <Binary>02000780E30500003F0900005B090000420ED1665C2BEE174B64529CB14610EA71000000</Binary> </EventData> </Event> What I have tried: ChkDsk on both C: (main drive) and D: (backup drive) doesn't find any errors. Running SFC /SCANNOW to run system file checker Checked the list of profiles at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList and ensured that each profile directory exists. I'm stumped; WHAT file can't be found and why is my backup failing? This is on a Lenovo T420 laptop.

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  • BSOD & System Failure after trying to install a new RAM

    - by Praveen Kumar
    I have updated the question with sections, so that people won't find it difficult to read. Basic System Information Let me give a basic introduction on my system. I have a system of following configuration: Processor: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz 3.40GHz RAM: Corsair Vengeance - 4GB Single Module DDR3 Memory Kit (CMZ4GX3M1A1600C9) x 2 OS: Windows 7 Ultimate, SP1 Build 7601 HDD: 1 TB Seagate 7200 RPM The Problem It was working fine for about an year. Yesterday I planned to increase my RAM to 16 GB by putting another set of two Corsair Vengeance - 4GB Single Module DDR3 Memory Kit (CMZ4GX3M1A1600C9). I got it from an authorized reseller and also, the RAM was fitted by a service engineer only. After the RAM was fit (all the four), the system failed to start, with an error code of 0x000000f4. The complete information of it is: Problem signature: Problem Event Name: BlueScreen OS Version: 6.1.7601.2.1.0.256.1 Locale ID: 16393 Additional information about the problem: BCCode: f4 BCP1: 0000000000000003 BCP2: FFFFFA8008A39060 BCP3: FFFFFA8008A39340 BCP4: FFFFF800037C8510 OS Version: 6_1_7601 Service Pack: 1_0 Product: 256_1 Files that help describe the problem: C:\Windows\Minidump\093012-13041-01.dmp C:\Users\Praveen Kumar\AppData\Local\Temp\WER-30716-0.sysdata.xml Read our privacy statement online: http://go.microsoft.com/fwlink/?linkid=104288&clcid=0x0409 If the online privacy statement is not available, please read our privacy statement offline: C:\Windows\system32\en-US\erofflps.txt Another Problem We first thought that it was the RAM, which caused the issue. So I returned the RAMs and now my computer configuration is exactly how it was the previous day. But, following the removal of the RAM, I also had several crashes after that. One suspicious thing was with an error code c0000134: STOP: c0000135 The program can’t start because %hs is missing from your computer . Try resintalling the program to fix this problem. After reading contents from this, this and this, which were never my case, they didn't help me. But I didn't receive any more STOP c0000134 messages. But this 0x000000f4 keeps on coming. I am writing from the same system and it allows me to work for say, half an hour max. Then I hear a device disconnect sound, the one you hear in Windows 7, when a USB Mass Storage Device is plugged out. Immediately following that, my screen goes blank and I get 0x000000f4 blue screen. Okay, now I am really concerned about my Hard Disk data, but I have no clue if there is a problem with the HDD. My Question What all files do I need to submit for your reference? Can this issue be fixed? I am getting more time if I remove my RAM, clean it and then put it back. Weird! Hope I have given the necessary information to help you guys. Thanks in advance. Minidumps I have uploaded all the Minidump DMP files from C:\Windows\Minidump folder here: http://www.praveen-kumar.com/Minidumps.zip Let me know if you face any issues in accessing it. Will be able to share elsewhere. Updates 30-Sep-2012 10:15 AM IST: When I keep the system cover opened, pressed the HDD Cable well, it is allowing me to be on for about half an hour, I guess? Also, I feel that the CPU fan speed is kind of slow. It rotates at around 900 RPM, but the CPU Temperature is not more than 70° C. 30-Sep-2012 10:30 AM IST: My Modem (Beetel 220BX ADSL2+ Router) failed. I have no idea how it is related to this issue, but I thought that I need to document this too. I really have a bad day here. 30-Sep-2012 11:00 AM IST: System still running fine, with the cabinet cover open, now for about an hour. 30-Sep-2012 12:00 PM IST: I shut down the system and closed the cabinet. Started the system, and it hung after giving the password. After a few minutes, got the same 0x000000f4 error. So, while it is in the upright position, fixed the Hard Disk cable and now it is booting fine. Waiting for more observations and answers.

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  • Why won't my AJAX controls work? (and ajax for .net 4 not working?)

    - by Nicklamort
    I'm totally new to ajax. I'm using VS2005. I just downloaded .NET framework 4 and so then I downloaded ajaxcontroltoolkit.binary.net4 via [http://ajaxcontroltoolkit.codeplex.com/releases/view/43475] (as opposed to ajaxcontroltoolkit.binary.net35 for .NET 3.5), but when I try to load the ajaxcontroltoolkit.dll into my toolbox (as said in the tutorials), I get the following error msg: "'C:......\ajaxcontroltoolkit.dll' is not a microsoft .NET module." First question: Why is this happening? So I tried downloading the "Recommended" ajaxcontroltoolkit.binary.net35, and it accepted the .dll file and loaded all my controls. So, I started a new website and tried to check out a combobox, and it displays, but IE is giving the follow error msg: 'Sys.Extended.UI.PositioningMode.BottomLeft' is null or not an object.' 2nd question: Why is this happening? LOL Thank you. <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> <%@ Register Assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" Namespace="System.Web.UI" TagPrefix="asp" %> <%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajx" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>Untitled Page</title> </head> <body> <form id="form1" runat="server"> <div> <asp:ScriptManager runat="server"> </asp:ScriptManager> <ajx:ComboBox ID="ComboBox1" runat="server"> </ajx:ComboBox> </div> </form> </body> </html> Here is my web.config: <?xml version="1.0"?> <configuration> <configSections> <sectionGroup name="system.web.extensions" type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"> <sectionGroup name="scripting" type="System.Web.Configuration.ScriptingSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"> <section name="scriptResourceHandler" type="System.Web.Configuration.ScriptingScriptResourceHandlerSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" allowDefinition="MachineToApplication"/> <sectionGroup name="webServices" type="System.Web.Configuration.ScriptingWebServicesSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"> <section name="jsonSerialization" type="System.Web.Configuration.ScriptingJsonSerializationSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" allowDefinition="Everywhere"/> <section name="profileService" type="System.Web.Configuration.ScriptingProfileServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" allowDefinition="MachineToApplication"/> <section name="authenticationService" type="System.Web.Configuration.ScriptingAuthenticationServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" allowDefinition="MachineToApplication"/> </sectionGroup> </sectionGroup> </sectionGroup> </configSections> <appSettings/> <connectionStrings/> <system.web> <pages> <controls> <add tagPrefix="ajaxToolkit" namespace="AjaxControlToolkit" assembly="AjaxControlToolkit"/> <add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/> <add tagPrefix="asp" namespace="System.Web.UI.WebControls" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </controls> </pages> <compilation debug="true"> <assemblies> <add assembly="System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/> <add assembly="System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/> <add assembly="System.Data.DataSetExtensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/> <add assembly="System.Xml.Linq, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/> <add assembly="System.Web.Extensions.Design, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add assembly="System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/> <add assembly="System.Data.Linq, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/> </assemblies> </compilation> <httpHandlers> <remove verb="*" path="*.asmx"/> <add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add verb="GET,HEAD" path="ScriptResource.axd" validate="false" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </httpHandlers> <httpModules> <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </httpModules> <authentication mode="Windows"/> </system.web> <system.webServer> <validation validateIntegratedModeConfiguration="false"/> <modules> <remove name="ScriptModule"/> <add name="ScriptModule" preCondition="managedHandler" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </modules> <handlers> <remove name="WebServiceHandlerFactory-Integrated"/> <remove name="ScriptHandlerFactory"/> <remove name="ScriptHandlerFactoryAppServices"/> <remove name="ScriptResource"/> <add name="ScriptHandlerFactory" verb="*" path="*.asmx" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add name="ScriptHandlerFactoryAppServices" verb="*" path="*_AppService.axd" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add name="ScriptResource" verb="GET,HEAD" path="ScriptResource.axd" preCondition="integratedMode" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </handlers> </system.webServer> </configuration>

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  • Dell PowerEdge R410: System asks to press F1 or F2

    - by hurikhan77
    We just installed an option card (PERC 6/i) into a brand-new Dell PowerEdge R410 and now the system does no unattended startup but instead asks me to press F1 to continue or F2 to enter system setup after printing the following message on the console: Fan 4 speed may change depending on system configuration and option card install. How do I make the system ignore this "problem" or whatever that is? This system is going to be installed at a remote data center and needs to be able to restart unattended. I do not want to ignore errors completely to not get endless restart loops in case of errors.

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  • HP Recovery options: System Recovery not showing

    - by sha404
    I am using HP Pavilion dv4 notebook. Previously, there were following options in Recovery Manager(using f11 during boot): +System Recovery +Factory Restore +Minimized Image Recovery The System Recovery option allows me to restore only Operating system drive e.g. C:\ drive, keeping all other user (me) created hard drives intact. I made a set of recovery disk. Since then I don't see the System Recovery option in HP Recovery Manager. But all other options are still there. But when I use recovery disks that i created earlier, that option e.g. System Recovery is shown. But It's really boring and time consuming to use disks for recovery. So, what's the problem with internal HP Recovery Manager? Why isn't it showing that option?

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  • Patch Management and System Inventory on a Windows network?

    - by Scott
    What are some good ways to have patch management and systems/hardware inventory for a Windows (Server 2003 or 2008) network? For example, at a minimum knowing the basics for all the machines out on the network such as OS version, patch level, what hotfixes they have, processor, ram, etc. Even better would be knowing more details such as peripherals. Ideally if there were a way to push service packs, and hotfixes (and other software?) to the machines, that would be great. What are some options for this?

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  • What system of administrative e-mail addresses does your organization use?

    - by Draco Flangetastic
    I'm getting ready to request a new batch of administrative e-mail addresses to replace an outdated hierarchy within my organization. I have the opportunity of choosing new aliases for 24/7 alert recipients, monitoring recipients, all team members, etc. What does your org use for these purposes? Groups in my org use things like: org-dept@, org-dept-all@, org-dept-alert@, org-dept-monitoring@, org-dept-status@. TIA!!!!!111

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  • Difference between “system-on-chip” and “CPU”

    - by Tim
    Very confused, in some websites, they have this line: iPhone 5s CPU: Apple A7 other websites saying that: iPhone 5s System-on-chip: Apple 7 CPU: 1.3 GHz 64bit dual core other sources saying that iPhone 5s System-on-chip: Apple 7 CPU: 1.3 GHz 64bit dual core Apple 7 In Wikipedia, it said: The Apple A7 is a 64-bit system on a chip (SoC) designed by Apple Inc. It first appeared in the iPhone 5S, which was introduced on September 10, 2013. Apple states that it is up to twice as fast and has up to twice the graphics power compared to its predecessor, the Apple A6. While not the first 64-bit ARM CPU, it is the first to ship in a consumer smartphone or tablet computer. There are 2 sentences: The Apple A7 is a 64-bit system on a chip (SoC) and While not the first 64-bit ARM CPU Wikipedia also said “The A7 features an Apple-designed 64-bit 1.3–1.4 GHz ARMv8-A dual-core CPU, called Cyclone”. So System on chip is also CPU? very confused

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  • How do I stop Mac OS X Snow Leopard from losing the keyboard shortcuts I create in System Preferences?

    - by Philip
    I can't explain it. In OS X 10.6.6 (but also in previous versions; nothing to do w/ latest update), I create some keyboard shortcuts both for individual applications and for "all applications." I use them for a while. Later, sometimes after restart sometimes not, they're gone. Where'd they go?!?! (More importantly, how do I make them stop disappearing? Less ideal solution: how do I back them up and quickly restore them?) Thanks!

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  • Software update shows "P??roblem with the system installer tool" error in OS X Lion

    - by Elnaz Shahmehr
    I can't update my system. Does anyone know what the problem is? sudo softwareupdate -i -a Password: Software Update Tool Copyright 2002-2010 Apple Downloading Digital Camera Raw Compatibility Update Waiting to install Digital Camera Raw Compatibility Update Downloading Java for OS X 2012-002 Verifying Java for OS X 2012-002 Waiting to install Java for OS X 2012-002 Downloading iTunes Waiting to install iTunes Downloading Safari Verifying Safari Waiting to install Safari Checking packages… Installing Waiting for other installations to complete… Validating packages… Writing files… Package failed: There was a problem with the system installer tool. Package failed: There was a problem with the system installer tool. Package failed: There was a problem with the system installer tool. Package failed: There was a problem with the system installer tool. Done.

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  • SQL SERVER – Find Max Worker Count using DMV – 32 Bit and 64 Bit

    - by pinaldave
    During several recent training courses, I found it very interesting that Worker Thread is not quite known to everyone despite the fact that it is a very important feature. At some point in the discussion, one of the attendees mentioned that we can double the Worker Thread if we double the CPU (add the same number of CPU that we have on current system). The same discussion has triggered this quick article. Here is the DMV which can be used to find out Max Worker Count SELECT max_workers_count FROM sys.dm_os_sys_info Let us run the above query on my system and find the results. As my system is 32 bit and I have two CPU, the Max Worker Count is displayed as 512. To address the previous discussion, adding more CPU does not necessarily double the Worker Count. In fact, the logic behind this simple principle is as follows: For x86 (32-bit) upto 4 logical processors  max worker threads = 256 For x86 (32-bit) more than 4 logical processors  max worker threads = 256 + ((# Procs – 4) * 8) For x64 (64-bit) upto 4 logical processors  max worker threads = 512 For x64 (64-bit) more than 4 logical processors  max worker threads = 512+ ((# Procs – 4) * 8) In addition to this, you can configure the Max Worker Thread by using SSMS. Go to Server Node >> Right Click and Select Property >> Select Process and modify setting under Worker Threads. According to Book On Line, the default Worker Thread settings are appropriate for most of the systems. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL System Table, SQL Tips and Tricks, T SQL, Technology Tagged: SQL DMV

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  • Proper way to remove an active / inactive LVM snapshot

    - by user2622247
    I have created a sample ruby script file for removing extra LVM snapshots from the system. For removing LVM snapshot, we are using lvremove command. This command is working fine and we can remove snapshots from the system. # sudo lvremove /dev/ops/dbbackup lvremove -- do you really want to remove "/dev/ops/dbbackup"? [y/n]: y Sometimes while removing snapshots we are getting following errors. Unable to deactivate open rootfs_12.10_20140812_00-cow (252:8) Failed to resume rootfs_12.10_20140812_00. libdevmapper exiting with 7 device(s) still suspended. The system gets frozen. We cannot fire any command or can not perform any action on it. After restarting the system, it is functioning fine. We can perform all the operations even we can delete that snapshot also. I searched about it I found these threads https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=659762 and https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=674682 Solution from this thread is after getting the error but I have to avoid this type of error. I have a question, Is there any better way removing LVM snapshots? So that we can avoid this type of error. If anyone needs more info feel free to ask me.

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  • php script dies when it calls a bash script, maybe a problem of server configuration

    - by user347501
    Hi!!! I have some problems with a PHP script that calls a Bash script.... in the PHP script is uploaded a XML file, then the PHP script calls a Bash script that cut the file in portions (for example, is uploaded a XML file of 30,000 lines, so the Bash script cut the file in portions of 10,000 lines, so it will be 3 files of 10,000 each one) The file is uploaded, the Bash script cut the lines, but when the Bash script returns to the PHP script, the PHP script dies, & I dont know why... I tested the script in another server and it works fine... I dont believe that is a memory problem, maybe it is a processor problem, I dont know, I dont know what to do, what can I do??? (Im using the function shell_exec in PHP to call the Bash script) The error only happens if the XML file has more than 8,000 lines, but if the file has less then 8,000 everything is ok (this is relative, it depends of the amount of data, of strings, of letters that contains each line) what can you suggest me??? (sorry for my bad english, I have to practice a lot xD) I leave the code here PHP script (at the end, after the ?, there is html & javascript code, but it doesnt appear, only the javascript code... basically the html is only to upload the file) " . date('c') . ": $str"; $file = fopen("uploadxmltest.debug.txt","a"); fwrite($file,date('c') . ": $str\n"); fclose($file); } try{ if(is_uploaded_file($_FILES['tfile']['tmp_name'])){ debug("step 1: the file was uploaded"); $norg=date('y-m-d')."_".md5(microtime()); $nfle="testfiles/$norg.xml"; $ndir="testfiles/$norg"; $ndir2="testfiles/$norg"; if(move_uploaded_file($_FILES['tfile']['tmp_name'],"$nfle")){ debug("step 2: the file was moved to the directory"); debug("memory_get_usage(): " . memory_get_usage()); debug("memory_get_usage(true): " . memory_get_usage(true)); debug("memory_get_peak_usage(): " . memory_get_peak_usage()); debug("memory_get_peak_usage(true): " . memory_get_peak_usage(true)); $shll=shell_exec("./crm_cutfile_v2.sh \"$nfle\" \"$ndir\" \"$norg\" "); debug("result: $shll"); debug("memory_get_usage(): " . memory_get_usage()); debug("memory_get_usage(true): " . memory_get_usage(true)); debug("memory_get_peak_usage(): " . memory_get_peak_usage()); debug("memory_get_peak_usage(true): " . memory_get_peak_usage(true)); debug("step 3: the file was cutted. END"); } else{ debug("ERROR: I didnt move the file"); exit(); } } else{ debug("ERROR: I didnt upload the file"); //exit(); } } catch(Exception $e){ debug("Exception: " . $e-getMessage()); exit(); } ? Test function uploadFile(){ alert("start"); if(document.test.tfile.value==""){ alert("First you have to upload a file"); } else{ document.test.submit(); } } Bash script with AWK #!/bin/bash #For single messages (one message per contact) function cutfile(){ lines=$( cat "$1" | awk 'END {print NR}' ) fline="$4"; if [ -d "$2" ]; then exsts=1 else mkdir "$2" fi cp "$1" "$2/datasource.xml" cd "$2" i=1 contfile=1 while [ $i -le $lines ] do currentline=$( cat "datasource.xml" | awk -v fl=$i 'NR==fl {print $0}' ) #creates first file if [ $i -eq 1 ]; then echo "$fline" "$3_1.txt" else #creates the rest of files when there are more than 10,000 contacts rsd=$(( ( $i - 2 ) % 10000 )) if [ $rsd -eq 0 ]; then echo "" "$3_$contfile.txt" contfile=$(( $contfile + 1 )) echo "$fline" "$3_$contfile.txt" fi fi echo "$currentline" "$3_$contfile.txt" i=$(( $i + 1 )) done echo "" "$3_$contfile.txt" return 1 } #For multiple messages (one message for all contacts) function cutfile_multi(){ return 1 } cutfile "$1" "$2" "$3" "$4" echo 1 thanks!!!!! =D

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  • Where can I find information on the Get, Set and Address methods for multidimensional System.Array i

    - by Rob Smallshire
    System.Array serves as the base class for all arrays in the Common Language Runtime (CLR). According to this article, For each concrete array type, [the] runtime adds three special methods: Get/Set/Address. and indeed if I disassemble this C# code, int[,] x = new int[1024,1024]; x[0,0] = 1; x[1,1] = 2; x[2,2] = 3; Console.WriteLine(x[0,0]); Console.WriteLine(x[1,1]); Console.WriteLine(x[2,2]); into CIL I get, IL_0000: ldc.i4 0x400 IL_0005: ldc.i4 0x400 IL_000a: newobj instance void int32[0...,0...]::.ctor(int32, int32) IL_000f: stloc.0 IL_0010: ldloc.0 IL_0011: ldc.i4.0 IL_0012: ldc.i4.0 IL_0013: ldc.i4.1 IL_0014: call instance void int32[0...,0...]::Set(int32, int32, int32) IL_0019: ldloc.0 IL_001a: ldc.i4.1 IL_001b: ldc.i4.1 IL_001c: ldc.i4.2 IL_001d: call instance void int32[0...,0...]::Set(int32, int32, int32) IL_0022: ldloc.0 IL_0023: ldc.i4.2 IL_0024: ldc.i4.2 IL_0025: ldc.i4.3 IL_0026: call instance void int32[0...,0...]::Set(int32, int32, int32) IL_002b: ldloc.0 IL_002c: ldc.i4.0 IL_002d: ldc.i4.0 IL_002e: call instance int32 int32[0...,0...]::Get(int32, int32) IL_0033: call void [mscorlib]System.Console::WriteLine(int32) IL_0038: ldloc.0 IL_0039: ldc.i4.1 IL_003a: ldc.i4.1 IL_003b: call instance int32 int32[0...,0...]::Get(int32, int32) IL_0040: call void [mscorlib]System.Console::WriteLine(int32) IL_0045: ldloc.0 IL_0046: ldc.i4.2 IL_0047: ldc.i4.2 IL_0048: call instance int32 int32[0...,0...]::Get(int32, int32) IL_004d: call void [mscorlib]System.Console::WriteLine(int32) where the calls to the aforementioned Get and Set methods can be clearly seen. It seems the arity of these methods is related to the dimensionality of the array, which is presumably why they are created by the runtime and are not pre-declared. I couldn't locate any information about these methods on MSDN and their simple names makes them resistant to Googling. I'm writing a compiler for a language which supports multidimensional arrays, so I'd like to find some official documentation about these methods, under what conditions I can expect them to exist and what I can expect their signatures to be. In particular, I'd like to know whether its possible to get a MethodInfo object for Get or Set for use with Reflection.Emit without having to create an instance of the array with correct type and dimensionality on which to reflect, as is done in the linked example.

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  • Designing an email system to guarantee delivery

    - by GlenH7
    We are looking to expand our use of email for notification purposes. We understand it will generate more inbox volume, but we are being selective about which events we fire notification on in order to keep the signal-to-noise ratio high. The big question we are struggling with is designing a system that guarantees that the email was delivered. If an email isn't delivered, we will consider that an exception event that needs to be investigated. In reality, I say almost guarantees because there aren't any true guarantees with email. We're just looking for a practical solution to making sure the email got there and experiences others have had with the various approaches to guaranteeing delivery. For the TL;DR crowd - how do we go about designing a system to guarantee delivery of emails? What techniques should we consider so we know the emails were delivered? Our biggest area of concern is what techniques to use so that we know when a message is sent out that it either lands in an inbox or it failed and we need to do something else. Additional requirements: We're not at the stage of including an escalation response, but we'll want that in the future or so we think. Most notifications will be internal to our enterprise, but we will have some notifications being sent to external clients. Some of our application is in a hosted environment. We haven't determined if those servers can access our corporate email servers for relaying or if they'll be acting as their own mail servers. Base design / modules (at the moment): A module to assign tracking identification A module to send out emails A module to receive delivery notification (perhaps this is the same as the email module) A module that checks sent messages against delivery notification and alerts on undelivered email. Some references: Atwood: Send some email Email Tracking Some approaches: Request a response (aka read-receipt or Message Disposition Notification). Seems prone to failure since we have cross-compatibility issues due to differing mail servers and software. Return receipt (aka Delivery Status Notification). Not sure if all mail servers honor this request or not Require an action and therefore prove reply. Seems burdensome to force the recipients to perform an additional task not related to resolving the issue. And no, we haven't come up with a way of linking getting the issue fixed to whether or not the email was received. Force a click-through / Other site sign-in. Similar to requiring some sort of action, this seems like an additional burden and will annoy the users. On the other hand, it seems the most likely to guarantee someone received the notification. Hidden image tracking. Not all email providers automatically load the image, and how would we associate the image(s) with the email tracking ID? Outsource delivery. This gets us out of the email business, but goes back to how to guarantee the out-sourcer's receipt and subsequent delivery to the end recipient. As a related concern, there will be an n:n relationship between issue notification and recipients. The 1 issue : n recipients subset isn't as much of a concern although if we had a delivery failure we would want to investigate and fix the core issue. Of bigger concern is n issues : 1 recipient, and we're specifically concerned in making sure that all n issues were received by the recipient. How does forum software or issue tracking software handle this requirement? If a tracking identifier is used, Where is it placed in the email? In the Subject, or the Body?

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  • Designing An ACL Based Permission System

    - by ryanzec
    I am trying to create a permissions system where everything is going to be stored in MySQL (or some database) and pulled using PHP for a project management system I am building.  I am right now trying to do it is an ACL kind of way.  There are a number key features I want to be able to support: 1.  Being able to assign permissions without being tied to a specific object. The reason for this is that I want to be able to selectively show/hide elements of the UI based on permissions at a point where I am not directly looking at a domain object instance.  For instance, a button to create a new project should only should only be shown to users that have the pm.project.create permission but obviously you can assign a create permission to an domain object instance (as it is already created). 2.  Not have to assign permissions for every single object. Obviously creating permissions entries for every single object (projects, tickets, comments, etc…) would become a nightmare to maintain so I want to have some level of permission inheritance. *3.  Be able to filter queries based on permissions. This would be a really nice to have but I am not sure if it is possible.  What I mean by this is say I have a page that list all projects.  I want the query that pulls all projects to incorporate the ACL so that it would not show projects that the current user does not have pm.project.read access to.  This would have to be incorporated into the main query as if it is a process that is done after that main query (which I know I could do) certain features like pagination become much more difficult. Right now this is my basic design for the tables: AclEntities id - the primary key key - the unique identifier for the domain object (usually the primary key of that object) parentId - the parent of the domain object (like the project object if this was a ticket object) aclDomainObjectId - metadata about the domain object AclDomainObjects id - primary key title - simple string to unique identify the domain object(ie. project, ticket, comment, etc…) fullyQualifiedClassName - the fully qualified class name for use in code (I am using namespaces) There would also be tables mapping AclEntities to Users and UserGroups. I also have this interface that all acl entity based object have to implement: IAclEntity getAclKey() - to the the unique key for this specific instance of the acl domain object (generally return the primary key or a concatenated string of a composite primary key) getAclTitle() - to get the unique title for the domain object (generally just returning a static string) getAclDisplayString() - get the string that represents this entity (generally one or more field on the object) getAclParentEntity() - get the parent acl entity object (or null if no parent) getAclEntity() - get the acl enitty object for this instance of the domain object (or null if one has not been created yet) hasPermission($permissionString, $user = null) - whether or not the user has the permission for this instance of the domain object static getFromAclEntityId($aclEntityId) - get a specific instance of the domain object from an acl entity id. Do any of these features I am looking for seems hard to support or are just way off base? Am I missing or not taking in account anything in my implementation? Is performance something I should keep in mind?

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  • Help understand GLSL directional light on iOS (left handed coord system)

    - by Robse
    I now have changed from GLKBaseEffect to a own shader implementation. I have a shader management, which compiles and applies a shader to the right time and does some shader setup like lights. Please have a look at my vertex shader code. Now, light direction should be provided in eye space, but I think there is something I don't get right. After I setup my view with camera I save a lightMatrix to transform the light from global space to eye space. My modelview and projection setup: - (void)setupViewWithWidth:(int)width height:(int)height camera:(N3DCamera *)aCamera { aCamera.aspect = (float)width / (float)height; float aspect = aCamera.aspect; float far = aCamera.far; float near = aCamera.near; float vFOV = aCamera.fieldOfView; float top = near * tanf(M_PI * vFOV / 360.0f); float bottom = -top; float right = aspect * top; float left = -right; // projection GLKMatrixStackLoadMatrix4(projectionStack, GLKMatrix4MakeFrustum(left, right, bottom, top, near, far)); // identity modelview GLKMatrixStackLoadMatrix4(modelviewStack, GLKMatrix4Identity); // switch to left handed coord system (forward = z+) GLKMatrixStackMultiplyMatrix4(modelviewStack, GLKMatrix4MakeScale(1, 1, -1)); // transform camera GLKMatrixStackMultiplyMatrix4(modelviewStack, GLKMatrix4MakeWithMatrix3(GLKMatrix3Transpose(aCamera.orientation))); GLKMatrixStackTranslate(modelviewStack, -aCamera.position.x, -aCamera.position.y, -aCamera.position.z); } - (GLKMatrix4)modelviewMatrix { return GLKMatrixStackGetMatrix4(modelviewStack); } - (GLKMatrix4)projectionMatrix { return GLKMatrixStackGetMatrix4(projectionStack); } - (GLKMatrix4)modelviewProjectionMatrix { return GLKMatrix4Multiply([self projectionMatrix], [self modelviewMatrix]); } - (GLKMatrix3)normalMatrix { return GLKMatrix3InvertAndTranspose(GLKMatrix4GetMatrix3([self modelviewProjectionMatrix]), NULL); } After that, I save the lightMatrix like this: [self.renderer setupViewWithWidth:view.drawableWidth height:view.drawableHeight camera:self.camera]; self.lightMatrix = [self.renderer modelviewProjectionMatrix]; And just before I render a 3d entity of the scene graph, I setup the light config for its shader with the lightMatrix like this: - (N3DLight)transformedLight:(N3DLight)light transformation:(GLKMatrix4)matrix { N3DLight transformedLight = N3DLightMakeDisabled(); if (N3DLightIsDirectional(light)) { GLKVector3 direction = GLKVector3MakeWithArray(GLKMatrix4MultiplyVector4(matrix, light.position).v); direction = GLKVector3Negate(direction); // HACK -> TODO: get lightMatrix right! transformedLight = N3DLightMakeDirectional(direction, light.diffuse, light.specular); } else { ... } return transformedLight; } You see the line, where I negate the direction!? I can't explain why I need to do that, but if I do, the lights are correct as far as I can tell. Please help me, to get rid of the hack. I'am scared that this has something to do, with my switch to left handed coord system. My vertex shader looks like this: attribute highp vec4 inPosition; attribute lowp vec4 inNormal; ... uniform highp mat4 MVP; uniform highp mat4 MV; uniform lowp mat3 N; uniform lowp vec4 constantColor; uniform lowp vec4 ambient; uniform lowp vec4 light0Position; uniform lowp vec4 light0Diffuse; uniform lowp vec4 light0Specular; varying lowp vec4 vColor; varying lowp vec3 vTexCoord0; vec4 calcDirectional(vec3 dir, vec4 diffuse, vec4 specular, vec3 normal) { float NdotL = max(dot(normal, dir), 0.0); return NdotL * diffuse; } ... vec4 calcLight(vec4 pos, vec4 diffuse, vec4 specular, vec3 normal) { if (pos.w == 0.0) { // Directional Light return calcDirectional(normalize(pos.xyz), diffuse, specular, normal); } else { ... } } void main(void) { // position highp vec4 position = MVP * inPosition; gl_Position = position; // normal lowp vec3 normal = inNormal.xyz / inNormal.w; normal = N * normal; normal = normalize(normal); // colors vColor = constantColor * ambient; // add lights vColor += calcLight(light0Position, light0Diffuse, light0Specular, normal); ... }

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  • Changing the Operating System with only Ubuntu installed

    - by Games Brainiac
    I really wanted to dive into the world of Open Source operating systems, so I downloaded the latest version of Ubuntu (13.10), and installed it on a clean(no operating system installed, absolutely nothing) Lenovo ThinkPad machine. After a few days, I wanted to try out a different Operating System (Elementary OS). I downloaded the ISO file, burned it to a USB, tested that the USB booted from a different computer (I have 2, one is the Lenovo, the other a HP). I was able to get the bootscreen, and everything worked like a charm after I set the BIOS to boot from USB Disk Drive instead of HD. After this, I went back to Lenovo, and tried to open up the boot menu, by pressing F12, so that I could load from a temporary device. To my surprise, nothing but the HD was listed. There was no Optical Drive, No USB Drive, absolutely nothing. So, I thought that these devices were probably disabled. So I went into my BIOS and checked to see what was the case. I saw that all my devices were enabled. USB and all the other devices such as network cable and the rest were all enabled. So, I thought this probably had something to do wit UEFI and Legacy Boot options. So, I made sure that both were enabled. This did not solve the problem either. Again, I got nothing but the option to boot from my Hard Disk. I thought the USB had to be at fault. I tried different ports, but to no avail. Next, I tried with a Live CD, which had Ubuntu on it. This failed too. I simply could not boot from anything other than my hard disk. Okay, so at this point, I was pretty desperate, so I installed Boot-Repair through: sudo add-apt-repository ppa:yannubuntu/boot-repair sudo apt-get update sudo apt-get install boot-repair What this did is lead me to GRUB. Ideally, its just a screen that gives me the option to load from Ubuntu or Advanced Settings. The Advanced settings had nothing but Ubuntu options in it. So, I kept on pressing ESC and that led me to the the grub console, and thats where I am right now with my Lenovo. I've also tried updating the BIOS, but Lenovo only has packages for Red Hat and Windows. So, a dead end there too. Right now, I need to know if there is any way that I can just delete everything from my Lenovo? I want to revert it back to its blank factory condition. How can I achieve this? I have tried to elaborate my problem as best I could. If there is any important information that I've missed out, please do not hesitate to leave a comment. I would have included some screen shots, but BIOS screen shots are a little hard to manage. However, I can provide a camera Image of the boot screen if needed (doing that as we speak).

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  • Random String Generator creates same string on multiple calls

    - by rockinthesixstring
    Hi there. I've build a random string generator but I'm having a problem whereby if I call the function multiple times say in a Page_Load method, the function returns the same string twice. here's the code ''' <summary>' ''' Generates a Random String' ''' </summary>' ''' <param name="n">number of characters the method should generate</param>' ''' <param name="UseSpecial">should the method include special characters? IE: # ,$, !, etc.</param>' ''' <param name="SpecialOnly">should the method include only the special characters and excludes alpha numeric</param>' ''' <returns>a random string n characters long</returns>' Public Function GenerateRandom(ByVal n As Integer, Optional ByVal UseSpecial As Boolean = True, Optional ByVal SpecialOnly As Boolean = False) As String Dim chars As String() ' a character array to use when generating a random string' Dim ichars As Integer = 74 'number of characters to use out of the chars string' Dim schars As Integer = 0 ' number of characters to skip out of the characters string' chars = { _ "A", "B", "C", "D", "E", "F", _ "G", "H", "I", "J", "K", "L", _ "M", "N", "O", "P", "Q", "R", _ "S", "T", "U", "V", "W", "X", _ "Y", "Z", "0", "1", "2", "3", _ "4", "5", "6", "7", "8", "9", _ "a", "b", "c", "d", "e", "f", _ "g", "h", "i", "j", "k", "l", _ "m", "n", "o", "p", "q", "r", _ "s", "t", "u", "v", "w", "x", _ "y", "z", "!", "@", "#", "$", _ "%", "^", "&", "*", "(", ")", _ "-", "+"} If Not UseSpecial Then ichars = 62 ' only use the alpha numeric characters out of "char"' If SpecialOnly Then schars = 62 : ichars = 74 ' skip the alpha numeric characters out of "char"' Dim rnd As New Random() Dim random As String = String.Empty Dim i As Integer = 0 While i < n random += chars(rnd.[Next](schars, ichars)) System.Math.Max(System.Threading.Interlocked.Increment(i), i - 1) End While rnd = Nothing Return random End Function but if I call something like this Dim str1 As String = GenerateRandom(5) Dim str2 As String = GenerateRandom(5) the response will be something like this g*3Jq g*3Jq and the second time I call it, it will be 3QM0$ 3QM0$ What am I missing? I'd like every random string to be generated as unique.

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  • C# Web Service gets stuck waiting for lock, does not return

    - by blue
    We have a C#(2.0) application which talks to our server(in java) via web services. Lately we have started seeing following behavior in (ONLY)one of our lab machines(XP): Once in a while(every few days), one of the webservice request will just get stuck, will not return or timeout. Following is the stacktrace where it seem to be stuck. Have no clue what is going on here. Any pointer would be of great help. ESP EIP 05eceeec 7c90eb94 [GCFrame: 05eceeec] 05ecefbc 7c90eb94 [HelperMethodFrame_1OBJ: 05ecefbc] System.Threading.Monitor.Enter(System.Object) 05ecf014 7a5b0034 System.Net.ConnectionGroup.Disassociate(System.Net.Connection) 05ecf040 7a5aeaa7 System.Net.Connection.PrepareCloseConnectionSocket(System.Net.ConnectionReturnResult ByRef) 05ecf0a4 7a5ac0e1 System.Net.Connection.ReadStartNextRequest(System.Net.WebRequest, System.Net.ConnectionReturnResult ByRef) 05ecf0e8 7a5b1119 System.Net.ConnectStream.CallDone(System.Net.ConnectionReturnResult) 05ecf0fc 7a5b3b5a System.Net.ConnectStream.ReadChunkedSync(Byte[], Int32, Int32) 05ecf114 7a5b2b90 System.Net.ConnectStream.ReadWithoutValidation(Byte[], Int32, Int32, Boolean) 05ecf160 7a5b29cc System.Net.ConnectStream.Read(Byte[], Int32, Int32) 05ecf1a0 79473cab System.IO.StreamReader.ReadBuffer(Char[], Int32, Int32, Boolean ByRef) 05ecf1c4 79473bd6 System.IO.StreamReader.Read(Char[], Int32, Int32) 05ecf1e8 69c29119 System.Xml.XmlTextReaderImpl.ReadData() 05ecf1f8 69c2ad70 System.Xml.XmlTextReaderImpl.ParseDocumentContent() 05ecf20c 69c292d7 System.Xml.XmlTextReaderImpl.Read() 05ecf21c 69c2929d System.Xml.XmlTextReader.Read() 05ecf220 6991b3e7 System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(System.Web.Services.Protocols.SoapClientMessage, System.Net.WebResponse, System.IO.Stream, Boolean) 05ecf268 69919ed1 System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(System.String, System.Object[])

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  • A Communication System for XAML Applications

    - by psheriff
    In any application, you want to keep the coupling between any two or more objects as loose as possible. Coupling happens when one class contains a property that is used in another class, or uses another class in one of its methods. If you have this situation, then this is called strong or tight coupling. One popular design pattern to help with keeping objects loosely coupled is called the Mediator design pattern. The basics of this pattern are very simple; avoid one object directly talking to another object, and instead use another class to mediate between the two. As with most of my blog posts, the purpose is to introduce you to a simple approach to using a message broker, not all of the fine details. IPDSAMessageBroker Interface As with most implementations of a design pattern, you typically start with an interface or an abstract base class. In this particular instance, an Interface will work just fine. The interface for our Message Broker class just contains a single method “SendMessage” and one event “MessageReceived”. public delegate void MessageReceivedEventHandler( object sender, PDSAMessageBrokerEventArgs e); public interface IPDSAMessageBroker{  void SendMessage(PDSAMessageBrokerMessage msg);   event MessageReceivedEventHandler MessageReceived;} PDSAMessageBrokerMessage Class As you can see in the interface, the SendMessage method requires a type of PDSAMessageBrokerMessage to be passed to it. This class simply has a MessageName which is a ‘string’ type and a MessageBody property which is of the type ‘object’ so you can pass whatever you want in the body. You might pass a string in the body, or a complete Customer object. The MessageName property will help the receiver of the message know what is in the MessageBody property. public class PDSAMessageBrokerMessage{  public PDSAMessageBrokerMessage()  {  }   public PDSAMessageBrokerMessage(string name, object body)  {    MessageName = name;    MessageBody = body;  }   public string MessageName { get; set; }   public object MessageBody { get; set; }} PDSAMessageBrokerEventArgs Class As our message broker class will be raising an event that others can respond to, it is a good idea to create your own event argument class. This class will inherit from the System.EventArgs class and add a couple of additional properties. The properties are the MessageName and Message. The MessageName property is simply a string value. The Message property is a type of a PDSAMessageBrokerMessage class. public class PDSAMessageBrokerEventArgs : EventArgs{  public PDSAMessageBrokerEventArgs()  {  }   public PDSAMessageBrokerEventArgs(string name,     PDSAMessageBrokerMessage msg)  {    MessageName = name;    Message = msg;  }   public string MessageName { get; set; }   public PDSAMessageBrokerMessage Message { get; set; }} PDSAMessageBroker Class Now that you have an interface class and a class to pass a message through an event, it is time to create your actual PDSAMessageBroker class. This class implements the SendMessage method and will also create the event handler for the delegate created in your Interface. public class PDSAMessageBroker : IPDSAMessageBroker{  public void SendMessage(PDSAMessageBrokerMessage msg)  {    PDSAMessageBrokerEventArgs args;     args = new PDSAMessageBrokerEventArgs(      msg.MessageName, msg);     RaiseMessageReceived(args);  }   public event MessageReceivedEventHandler MessageReceived;   protected void RaiseMessageReceived(    PDSAMessageBrokerEventArgs e)  {    if (null != MessageReceived)      MessageReceived(this, e);  }} The SendMessage method will take a PDSAMessageBrokerMessage object as an argument. It then creates an instance of a PDSAMessageBrokerEventArgs class, passing to the constructor two items: the MessageName from the PDSAMessageBrokerMessage object and also the object itself. It may seem a little redundant to pass in the message name when that same message name is part of the message, but it does make consuming the event and checking for the message name a little cleaner – as you will see in the next section. Create a Global Message Broker In your WPF application, create an instance of this message broker class in the App class located in the App.xaml file. Create a public property in the App class and create a new instance of that class in the OnStartUp event procedure as shown in the following code: public partial class App : Application{  public PDSAMessageBroker MessageBroker { get; set; }   protected override void OnStartup(StartupEventArgs e)  {    base.OnStartup(e);     MessageBroker = new PDSAMessageBroker();  }} Sending and Receiving Messages Let’s assume you have a user control that you load into a control on your main window and you want to send a message from that user control to the main window. You might have the main window display a message box, or put a string into a status bar as shown in Figure 1. Figure 1: The main window can receive and send messages The first thing you do in the main window is to hook up an event procedure to the MessageReceived event of the global message broker. This is done in the constructor of the main window: public MainWindow(){  InitializeComponent();   (Application.Current as App).MessageBroker.     MessageReceived += new MessageReceivedEventHandler(       MessageBroker_MessageReceived);} One piece of code you might not be familiar with is accessing a property defined in the App class of your XAML application. Within the App.Xaml file is a class named App that inherits from the Application object. You access the global instance of this App class by using Application.Current. You cast Application.Current to ‘App’ prior to accessing any of the public properties or methods you defined in the App class. Thus, the code (Application.Current as App).MessageBroker, allows you to get at the MessageBroker property defined in the App class. In the MessageReceived event procedure in the main window (shown below) you can now check to see if the MessageName property of the PDSAMessageBrokerEventArgs is equal to “StatusBar” and if it is, then display the message body into the status bar text block control. void MessageBroker_MessageReceived(object sender,   PDSAMessageBrokerEventArgs e){  switch (e.MessageName)  {    case "StatusBar":      tbStatus.Text = e.Message.MessageBody.ToString();      break;  }} In the Page 1 user control’s Loaded event procedure you will send the message “StatusBar” through the global message broker to any listener using the following code: private void UserControl_Loaded(object sender,  RoutedEventArgs e){  // Send Status Message  (Application.Current as App).MessageBroker.    SendMessage(new PDSAMessageBrokerMessage("StatusBar",      "This is Page 1"));} Since the main window is listening for the message ‘StatusBar’, it will display the value “This is Page 1” in the status bar at the bottom of the main window. Sending a Message to a User Control The previous example sent a message from the user control to the main window. You can also send messages from the main window to any listener as well. Remember that the global message broker is really just a broadcaster to anyone who has hooked into the MessageReceived event. In the constructor of the user control named ucPage1 you can hook into the global message broker’s MessageReceived event. You can then listen for any messages that are sent to this control by using a similar switch-case structure like that in the main window. public ucPage1(){  InitializeComponent();   // Hook to the Global Message Broker  (Application.Current as App).MessageBroker.    MessageReceived += new MessageReceivedEventHandler(      MessageBroker_MessageReceived);} void MessageBroker_MessageReceived(object sender,  PDSAMessageBrokerEventArgs e){  // Look for messages intended for Page 1  switch (e.MessageName)  {    case "ForPage1":      MessageBox.Show(e.Message.MessageBody.ToString());      break;  }} Once the ucPage1 user control has been loaded into the main window you can then send a message using the following code: private void btnSendToPage1_Click(object sender,  RoutedEventArgs e){  PDSAMessageBrokerMessage arg =     new PDSAMessageBrokerMessage();   arg.MessageName = "ForPage1";  arg.MessageBody = "Message For Page 1";   // Send a message to Page 1  (Application.Current as App).MessageBroker.SendMessage(arg);} Since the MessageName matches what is in the ucPage1 MessageReceived event procedure, ucPage1 can do anything in response to that event. It is important to note that when the message gets sent it is sent to all MessageReceived event procedures, not just the one that is looking for a message called “ForPage1”. If the user control ucPage1 is not loaded and this message is broadcast, but no other code is listening for it, then it is simply ignored. Remove Event Handler In each class where you add an event handler to the MessageReceived event you need to make sure to remove those event handlers when you are done. Failure to do so can cause a strong reference to the class and thus not allow that object to be garbage collected. In each of your user control’s make sure in the Unloaded event to remove the event handler. private void UserControl_Unloaded(object sender, RoutedEventArgs e){  if (_MessageBroker != null)    _MessageBroker.MessageReceived -=         _MessageBroker_MessageReceived;} Problems with Message Brokering As with most “global” classes or classes that hook up events to other classes, garbage collection is something you need to consider. Just the simple act of hooking up an event procedure to a global event handler creates a reference between your user control and the message broker in the App class. This means that even when your user control is removed from your UI, the class will still be in memory because of the reference to the message broker. This can cause messages to still being handled even though the UI is not being displayed. It is up to you to make sure you remove those event handlers as discussed in the previous section. If you don’t, then the garbage collector cannot release those objects. Instead of using events to send messages from one object to another you might consider registering your objects with a central message broker. This message broker now becomes a collection class into which you pass an object and what messages that object wishes to receive. You do end up with the same problem however. You have to un-register your objects; otherwise they still stay in memory. To alleviate this problem you can look into using the WeakReference class as a method to store your objects so they can be garbage collected if need be. Discussing Weak References is beyond the scope of this post, but you can look this up on the web. Summary In this blog post you learned how to create a simple message broker system that will allow you to send messages from one object to another without having to reference objects directly. This does reduce the coupling between objects in your application. You do need to remember to get rid of any event handlers prior to your objects going out of scope or you run the risk of having memory leaks and events being called even though you can no longer access the object that is responding to that event. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “A Communication System for XAML Applications” from the drop down list.

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