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  • How to Reuse Your Old Wi-Fi Router as a Network Switch

    - by Jason Fitzpatrick
    Just because your old Wi-Fi router has been replaced by a newer model doesn’t mean it needs to gather dust in the closet. Read on as we show you how to take an old and underpowered Wi-Fi router and turn it into a respectable network switch (saving your $20 in the process). Image by mmgallan. Why Do I Want To Do This? Wi-Fi technology has changed significantly in the last ten years but Ethernet-based networking has changed very little. As such, a Wi-Fi router with 2006-era guts is lagging significantly behind current Wi-Fi router technology, but the Ethernet networking component of the device is just as useful as ever; aside from potentially being only 100Mbs instead of 1000Mbs capable (which for 99% of home applications is irrelevant) Ethernet is Ethernet. What does this matter to you, the consumer? It means that even though your old router doesn’t hack it for your Wi-Fi needs any longer the device is still a perfectly serviceable (and high quality) network switch. When do you need a network switch? Any time you want to share an Ethernet cable among multiple devices, you need a switch. For example, let’s say you have a single Ethernet wall jack behind your entertainment center. Unfortunately you have four devices that you want to link to your local network via hardline including your smart HDTV, DVR, Xbox, and a little Raspberry Pi running XBMC. Instead of spending $20-30 to purchase a brand new switch of comparable build quality to your old Wi-Fi router it makes financial sense (and is environmentally friendly) to invest five minutes of your time tweaking the settings on the old router to turn it from a Wi-Fi access point and routing tool into a network switch–perfect for dropping behind your entertainment center so that your DVR, Xbox, and media center computer can all share an Ethernet connection. What Do I Need? For this tutorial you’ll need a few things, all of which you likely have readily on hand or are free for download. To follow the basic portion of the tutorial, you’ll need the following: 1 Wi-Fi router with Ethernet ports 1 Computer with Ethernet jack 1 Ethernet cable For the advanced tutorial you’ll need all of those things, plus: 1 copy of DD-WRT firmware for your Wi-Fi router We’re conducting the experiment with a Linksys WRT54GL Wi-Fi router. The WRT54 series is one of the best selling Wi-Fi router series of all time and there’s a good chance a significant number of readers have one (or more) of them stuffed in an office closet. Even if you don’t have one of the WRT54 series routers, however, the principles we’re outlining here apply to all Wi-Fi routers; as long as your router administration panel allows the necessary changes you can follow right along with us. A quick note on the difference between the basic and advanced versions of this tutorial before we proceed. Your typical Wi-Fi router has 5 Ethernet ports on the back: 1 labeled “Internet”, “WAN”, or a variation thereof and intended to be connected to your DSL/Cable modem, and 4 labeled 1-4 intended to connect Ethernet devices like computers, printers, and game consoles directly to the Wi-Fi router. When you convert a Wi-Fi router to a switch, in most situations, you’ll lose two port as the “Internet” port cannot be used as a normal switch port and one of the switch ports becomes the input port for the Ethernet cable linking the switch to the main network. This means, referencing the diagram above, you’d lose the WAN port and LAN port 1, but retain LAN ports 2, 3, and 4 for use. If you only need to switch for 2-3 devices this may be satisfactory. However, for those of you that would prefer a more traditional switch setup where there is a dedicated WAN port and the rest of the ports are accessible, you’ll need to flash a third-party router firmware like the powerful DD-WRT onto your device. Doing so opens up the router to a greater degree of modification and allows you to assign the previously reserved WAN port to the switch, thus opening up LAN ports 1-4. Even if you don’t intend to use that extra port, DD-WRT offers you so many more options that it’s worth the extra few steps. Preparing Your Router for Life as a Switch Before we jump right in to shutting down the Wi-Fi functionality and repurposing your device as a network switch, there are a few important prep steps to attend to. First, you want to reset the router (if you just flashed a new firmware to your router, skip this step). Following the reset procedures for your particular router or go with what is known as the “Peacock Method” wherein you hold down the reset button for thirty seconds, unplug the router and wait (while still holding the reset button) for thirty seconds, and then plug it in while, again, continuing to hold down the rest button. Over the life of a router there are a variety of changes made, big and small, so it’s best to wipe them all back to the factory default before repurposing the router as a switch. Second, after resetting, we need to change the IP address of the device on the local network to an address which does not directly conflict with the new router. The typical default IP address for a home router is 192.168.1.1; if you ever need to get back into the administration panel of the router-turned-switch to check on things or make changes it will be a real hassle if the IP address of the device conflicts with the new home router. The simplest way to deal with this is to assign an address close to the actual router address but outside the range of addresses that your router will assign via the DHCP client; a good pick then is 192.168.1.2. Once the router is reset (or re-flashed) and has been assigned a new IP address, it’s time to configure it as a switch. Basic Router to Switch Configuration If you don’t want to (or need to) flash new firmware onto your device to open up that extra port, this is the section of the tutorial for you: we’ll cover how to take a stock router, our previously mentioned WRT54 series Linksys, and convert it to a switch. Hook the Wi-Fi router up to the network via one of the LAN ports (consider the WAN port as good as dead from this point forward, unless you start using the router in its traditional function again or later flash a more advanced firmware to the device, the port is officially retired at this point). Open the administration control panel via  web browser on a connected computer. Before we get started two things: first,  anything we don’t explicitly instruct you to change should be left in the default factory-reset setting as you find it, and two, change the settings in the order we list them as some settings can’t be changed after certain features are disabled. To start, let’s navigate to Setup ->Basic Setup. Here you need to change the following things: Local IP Address: [different than the primary router, e.g. 192.168.1.2] Subnet Mask: [same as the primary router, e.g. 255.255.255.0] DHCP Server: Disable Save with the “Save Settings” button and then navigate to Setup -> Advanced Routing: Operating Mode: Router This particular setting is very counterintuitive. The “Operating Mode” toggle tells the device whether or not it should enable the Network Address Translation (NAT)  feature. Because we’re turning a smart piece of networking hardware into a relatively dumb one, we don’t need this feature so we switch from Gateway mode (NAT on) to Router mode (NAT off). Our next stop is Wireless -> Basic Wireless Settings: Wireless SSID Broadcast: Disable Wireless Network Mode: Disabled After disabling the wireless we’re going to, again, do something counterintuitive. Navigate to Wireless -> Wireless Security and set the following parameters: Security Mode: WPA2 Personal WPA Algorithms: TKIP+AES WPA Shared Key: [select some random string of letters, numbers, and symbols like JF#d$di!Hdgio890] Now you may be asking yourself, why on Earth are we setting a rather secure Wi-Fi configuration on a Wi-Fi router we’re not going to use as a Wi-Fi node? On the off chance that something strange happens after, say, a power outage when your router-turned-switch cycles on and off a bunch of times and the Wi-Fi functionality is activated we don’t want to be running the Wi-Fi node wide open and granting unfettered access to your network. While the chances of this are next-to-nonexistent, it takes only a few seconds to apply the security measure so there’s little reason not to. Save your changes and navigate to Security ->Firewall. Uncheck everything but Filter Multicast Firewall Protect: Disable At this point you can save your changes again, review the changes you’ve made to ensure they all stuck, and then deploy your “new” switch wherever it is needed. Advanced Router to Switch Configuration For the advanced configuration, you’ll need a copy of DD-WRT installed on your router. Although doing so is an extra few steps, it gives you a lot more control over the process and liberates an extra port on the device. Hook the Wi-Fi router up to the network via one of the LAN ports (later you can switch the cable to the WAN port). Open the administration control panel via web browser on the connected computer. Navigate to the Setup -> Basic Setup tab to get started. In the Basic Setup tab, ensure the following settings are adjusted. The setting changes are not optional and are required to turn the Wi-Fi router into a switch. WAN Connection Type: Disabled Local IP Address: [different than the primary router, e.g. 192.168.1.2] Subnet Mask: [same as the primary router, e.g. 255.255.255.0] DHCP Server: Disable In addition to disabling the DHCP server, also uncheck all the DNSMasq boxes as the bottom of the DHCP sub-menu. If you want to activate the extra port (and why wouldn’t you), in the WAN port section: Assign WAN Port to Switch [X] At this point the router has become a switch and you have access to the WAN port so the LAN ports are all free. Since we’re already in the control panel, however, we might as well flip a few optional toggles that further lock down the switch and prevent something odd from happening. The optional settings are arranged via the menu you find them in. Remember to save your settings with the save button before moving onto a new tab. While still in the Setup -> Basic Setup menu, change the following: Gateway/Local DNS : [IP address of primary router, e.g. 192.168.1.1] NTP Client : Disable The next step is to turn off the radio completely (which not only kills the Wi-Fi but actually powers the physical radio chip off). Navigate to Wireless -> Advanced Settings -> Radio Time Restrictions: Radio Scheduling: Enable Select “Always Off” There’s no need to create a potential security problem by leaving the Wi-Fi radio on, the above toggle turns it completely off. Under Services -> Services: DNSMasq : Disable ttraff Daemon : Disable Under the Security -> Firewall tab, uncheck every box except “Filter Multicast”, as seen in the screenshot above, and then disable SPI Firewall. Once you’re done here save and move on to the Administration tab. Under Administration -> Management:  Info Site Password Protection : Enable Info Site MAC Masking : Disable CRON : Disable 802.1x : Disable Routing : Disable After this final round of tweaks, save and then apply your settings. Your router has now been, strategically, dumbed down enough to plod along as a very dependable little switch. Time to stuff it behind your desk or entertainment center and streamline your cabling.     

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  • Using Razor together with ASP.NET Web API

    - by Fredrik N
    On the blog post “If Then, If Then, If Then, MVC” I found the following code example: [HttpGet]public ActionResult List() { var list = new[] { "John", "Pete", "Ben" }; if (Request.AcceptTypes.Contains("application/json")) { return Json(list, JsonRequestBehavior.AllowGet); } if (Request.IsAjaxRequest()) [ return PartialView("_List", list); } return View(list); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The code is a ASP.NET MVC Controller where it reuse the same “business” code but returns JSON if the request require JSON, a partial view when the request is an AJAX request or a normal ASP.NET MVC View. The above code may have several reasons to be changed, and also do several things, the code is not closed for modifications. To extend the code with a new way of presenting the model, the code need to be modified. So I started to think about how the above code could be rewritten so it will follow the Single Responsibility and open-close principle. I came up with the following result and with the use of ASP.NET Web API: public String[] Get() { return new[] { "John", "Pete", "Ben" }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   It just returns the model, nothing more. The code will do one thing and it will do it well. But it will not solve the problem when it comes to return Views. If we use the ASP.NET Web Api we can get the result as JSON or XML, but not as a partial view or as a ASP.NET MVC view. Wouldn’t it be nice if we could do the following against the Get() method?   Accept: application/json JSON will be returned – Already part of the Web API   Accept: text/html Returns the model as HTML by using a View   The best thing, it’s possible!   By using the RazorEngine I created a custom MediaTypeFormatter (RazorFormatter, code at the end of this blog post) and associate it with the media type “text/html”. I decided to use convention before configuration to decide which Razor view should be used to render the model. To register the formatter I added the following code to Global.asax: GlobalConfiguration.Configuration.Formatters.Add(new RazorFormatter()); Here is an example of a ApiController that just simply returns a model: using System.Web.Http; namespace WebApiRazor.Controllers { public class CustomersController : ApiController { // GET api/values public Customer Get() { return new Customer { Name = "John Doe", Country = "Sweden" }; } } public class Customer { public string Name { get; set; } public string Country { get; set; } } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Because I decided to use convention before configuration I only need to add a view with the same name as the model, Customer.cshtml, here is the example of the View:   <!DOCTYPE html> <html> <head> <script src="http://ajax.aspnetcdn.com/ajax/jquery/jquery-1.5.1.min.js" type="text/javascript"></script> </head> <body> <div id="body"> <section> <div> <hgroup> <h1>Welcome '@Model.Name' to ASP.NET Web API Razor Formatter!</h1> </hgroup> </div> <p> Using the same URL "api/values" but using AJAX: <button>Press to show content!</button> </p> <p> </p> </section> </div> </body> <script type="text/javascript"> $("button").click(function () { $.ajax({ url: '/api/values', type: "GET", contentType: "application/json; charset=utf-8", success: function(data, status, xhr) { alert(data.Name); }, error: function(xhr, status, error) { alert(error); }}); }); </script> </html> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Now when I open up a browser and enter the following URL: http://localhost/api/customers the above View will be displayed and it will render the model the ApiController returns. If I use Ajax against the same ApiController with the content type set to “json”, the ApiController will now return the model as JSON. Here is a part of a really early prototype of the Razor formatter (The code is far from perfect, just use it for testing). I will rewrite the code and also make it possible to specify an attribute to the returned model, so it can decide which view to be used when the media type is “text/html”, but by default the formatter will use convention: using System; using System.Net.Http.Formatting; namespace WebApiRazor.Models { using System.IO; using System.Net; using System.Net.Http.Headers; using System.Reflection; using System.Threading.Tasks; using RazorEngine; public class RazorFormatter : MediaTypeFormatter { public RazorFormatter() { SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/html")); SupportedMediaTypes.Add(new MediaTypeHeaderValue("application/xhtml+xml")); } //... public override Task WriteToStreamAsync( Type type, object value, Stream stream, HttpContentHeaders contentHeaders, TransportContext transportContext) { var task = Task.Factory.StartNew(() => { var viewPath = // Get path to the view by the name of the type var template = File.ReadAllText(viewPath); Razor.Compile(template, type, type.Name); var razor = Razor.Run(type.Name, value); var buf = System.Text.Encoding.Default.GetBytes(razor); stream.Write(buf, 0, buf.Length); stream.Flush(); }); return task; } } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Summary By using formatters and the ASP.NET Web API we can easily just extend our code without doing any changes to our ApiControllers when we want to return a new format. This blog post just showed how we can extend the Web API to use Razor to format a returned model into HTML.   If you want to know when I will post more blog posts, please feel free to follow me on twitter:   @fredrikn

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  • Ubuntu 12.04 does not see windows already install on my computer (dual installation)

    - by jacinta
    I was trying to install the ubuntu 12.4 along side windows 7 on my new HP Pavilion 64k desktop with windows 7 computer but Ubuntu said that ( This computer has no detected operating system) and some one said (I suggest you chkdsk your Windows partition. I also suggest you resize the NTFS in WIndows then install Ubuntu to the free space.) Therefore I did (To shrink a simple or spanned volume using the Windows interface In Disk Management, right-click the simple or spanned volume you want to shrink. Click Shrink Volume…. Follow the instructions on your screen.) Then When I try to install ubuntu 12.4 after doing this, I received the same error. I was going to undo what I did but I see that I lose 1g when I do that so now what do I do? it says I can do a new simple volume and maybe then the space will no longer be unallocated. Please help me. I think I have a bad cd (ubuntu 12.4) cause from my research I see that I am not suppose to get a screen saying that (The computer has no detected operating system) I think this is a bad cd and I hope I did not mess up my computer. Please help. .................................................................................... O k I think I am following what you said about how to edit my question irrational john. I did chkdsk as you and actionparsnip (andrew-woodhead666) told me to AND ALSO did a lot of other things before I found out how to chkdsk. No problems. Thank you. Then I put back the space (extended) I took from system. I still was only able to put back 15 and not 16 so it is up to 99mb not back to 100mb. Then I shrank HP (C) as you told me, to 10 13,240 mb which is (12.93gb Unallocated). I did not change it into NTSF by doing the (New Simple Volume Action) I just left it. Then I tried to install UBUNTU 12.04 live CD amd64 and it gave me the results it was sometimes giving me before which is result (THAT Ubuntu) does not tell me weather I have or have not an already installed windows7. It just goes to a window that would have showed me information on what I have and on the bottom (DEVICE FOR BOOT LOADER INSTALLATION /dev/sda ) and the option to go BACK, QUIT, or INSTALL. (I think it is the INSTALLATION TYPE window). Therefore I do what I have been doing and I QUIT. What do I do now? Sorry that it seems like I cannot do anything on my own. On the Youtube video how to install ubuntu dual-boot alongside windows UBUNTU is installed so easy. The installation option page gives 3 options including dual instillation and the disk even lets you use a slider to slide to the size of the partition size you want. Yet my UBUNTU live cd is a mess and I checked it as one of you guys told me and got back information that it is good. Oh well this guy says you should press a control key to tell which device you are using to install ubuntu before the screen comes up. I guess cause it is old. This page also shows you easy stuff that do not show up on my cd. how to dual-boot UBUNTU and windows 7 P.S.. I saw this on the windows 7 website windows.microsoft.com/en-US/windows7/Formatting-disks-and-drives-frequently-asked-questions CREATE A BOOT PARTITION I HAD TO LEAVE OUT THE HTTP STUFF CAUSE I AM ONLY ALLOWED 2 ON A PAGE IT SAID To create a boot partition Warning Warning If you are installing different versions of Windows, you must install the earliest version first. If you don't do this, your computer may become inoperable. Open Computer Management by clicking the Start button Picture of the Start button, clicking Control Panel, clicking System and Security, clicking Administrative Tools, and then double-clicking Computer Management.? Administrator permission required If you're prompted for an administrator password or confirmation, type the password or provide confirmation. In the left pane, under Storage, click Disk Management. Right-click an unallocated region on your hard disk, and then click New Simple Volume. In the New Simple Volume Wizard, click Next. Type the size of the volume you want to create in megabytes (MB) or accept the maximum default size, and then click Next. Accept the default drive letter or choose a different drive letter to identify the volume, and then click Next. In the Format Partition dialog box, do one of the following: If you don't want to format the volume right now, click Do not format this volume, and then click Next. To format the volume with the default settings, click Next. For more information about formatting, see Formatting disks and drives: frequently asked questions. Review your choices, and then click Finish. AND THIS ON ANOTHER PAGE. Formatting disks and drives: frequently asked questions Hard disks, the primary storage devices on your computer, need to be formatted before you can use them. When you format a disk, you configure it with a file system so that Windows can store information on the disk. Hard disks in new computers running Windows are already formatted. If you buy an additional hard disk to expand the storage of your computer, you might need to format it. Storage devices such as USB flash drives and flash memory cards usually come preformatted by the manufacturer, so you probably won't need to format them. CDs and DVDs, on the other hand, use different formats from hard disks and removable storage devices. For information about formatting CDs and DVDs, see Which CD or DVD format should I use? Warning Warning Formatting erases any existing files on a hard disk. If you format a hard disk that has files on it, the files will be deleted. WHAT I DID WAS I GOT TO COMPUTER MANAGEMENT SECTION THEN I CLICKED ON DRIVE HP(C) (it put stripes on to show it is selected) Then I click on ACTION selected ALL TASKS AND THEN selected SHRINK VOLUME and then chose how much space from what it was giving me that I wanted. (12.93gb) AND THAT WAS ALL I DID. THEN I TRIED TO INSTALL UBUNTU i NEVER GOT THE 3RD SCREEN THAT IS IN THE VIDEO I INCLUDED (THE YOUTUBE WITH THE ENGLISH GUY) INSTALLATION TYPE I ALSO DID NOT GET THE 4TH SCREEN THAT ALLOWS YOU TO SELECT PARTITION SIZE what i got next was the 2nd INSTILLATION TYPE window shown on the (LINUX BS DOS.COM) PAGE THAT I INCLUDED and it showed no information about any drives (no drives /partition or stuff was shown) only the Boot Loader statement and the dev/sda bar and that's why i did not press install but chose to QUIT. SORRY I JUST NOW SAW YOUR ANSWER IRRATIONAL JOHN. I SHRANK HP(C) BY 12.93GB MY UNALLOCATED SPACE IS NOW 12.93GB HP(C) = 907.17gb NTSF...YOU ARE CORRECT WITH EVERYTHING YOU SAID This is what i read on (http://)windows.microsoft.com/en-US/windows7/Create-a-boot-partition I am only allowed 2 links Create a boot partition You must be logged on as an administrator to perform these steps. A boot partition is a partition that contains the files for the Windows operating system. If you want to install a second operating system on your computer (called a dual-boot or multiboot configuration), you need to create another partition on the hard disk, and then install the additional operating system on the new partition. Your hard disk would then have one system partition and two boot partitions. (A system partition is the partition that contains the hardware-related files. These tell the computer where to look to start Windows.) To create a partition on a basic disk, there must be unallocated disk space on your hard disk. With Disk Management, you can create a maximum of three primary partitions on a hard disk. You can create extended partitions, which include logical drives within them, if you need more partitions on the disk. Picture of disk space in Computer ManagementUnallocated disk space If there is no unallocated space, you will either need to create space by shrinking or deleting an existing partition or by using a third-party partitioning tool to repartition your hard disk. For more information, see Can I repartition my hard disk? To create a boot partition Warning Warning If you are installing different versions of Windows, you must install the earliest version first. If you don't do this, your computer may become inoperable. Open Computer Management by clicking the Start button Picture of the Start button, clicking Control Panel, clicking System and Security, clicking Administrative Tools, and then double-clicking Computer Management.? Administrator permission required If you're prompted for an administrator password or confirmation, type the password or provide confirmation. In the left pane, under Storage, click Disk Management. Right-click an unallocated region on your hard disk, and then click New Simple Volume. In the New Simple Volume Wizard, click Next. Type the size of the volume you want to create in megabytes (MB) or accept the maximum default size, and then click Next. Accept the default drive letter or choose a different drive letter to identify the volume, and then click Next. In the Format Partition dialog box, do one of the following: If you don't want to format the volume right now, click Do not format this volume, and then click Next. To format the volume with the default settings, click Next. For more information about formatting, see Formatting disks and drives: frequently asked questions. Review your choices, and then click Finish. I did what you told me @irrational john and this is the screen shot. I ENTERED ubuntu@ubuntu:~$ sudo os-prober computer did not respond so I entered ubuntu@ubuntu:~$ sudo apt-get -y remove dmraid computer responded with Reading package lists... Done Building dependency tree Reading state information... Done The following packages will be REMOVED: dmraid 0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded. After this operation, 141 kB disk space will be freed. (Reading database ... 147515 files and directories currently installed.) Removing dmraid ... update-initramfs is disabled since running on read-only media Processing triggers for man-db ... I entered ubuntu@ubuntu:~$ sudo os-prober Computer Responded with /dev/sda1:Windows 7 (loader):Windows:chain /dev/sda3:Windows Recovery Environment (loader):Windows1:chain ubuntu@ubuntu:~$ ............... @obsessiveFOSS I don't know what is a Grub menu and I do not know what is the Ubuntu boot option The answer you gave to me was correct. This one {This apparently removes the dmraid metadata. After doing that, you can use the desktop icon Install Ubuntu 12.04 LTS to start the Ubuntu installer. This time the Installation Type window should contain the option to Install Ubuntu alongside Windows 7.} This is what I decided to do. I did not see the rest of your help 'till now. Never the less. I think the best thing for me to do now is to get a cheap used laptop and either do a dual installation or just install Ubuntu on to it. This way if I have any issues that I cannot solve like the one I had here, at least I will still have a usable computer to work on and to use to get answers with because I am not an expert like the people on this forum. Thanks a lot I will try to keep learning and do research enough to some day help someone else.

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  • jQuery CSS Property Monitoring Plug-in updated

    - by Rick Strahl
    A few weeks back I had talked about the need to watch properties of an object and be able to take action when certain values changed. The need for this arose out of wanting to build generic components that could 'attach' themselves to other objects. One example is a drop shadow - if I add a shadow behavior to an object I want the shadow to be pinned to that object so when that object moves I also want the shadow to move with it, or when the panel is hidden the shadow should hide with it - automatically without having to explicitly hook up monitoring code to the panel. For example, in my shadow plug-in I can now do something like this (where el is the element that has the shadow attached and sh is the shadow): if (!exists) // if shadow was created el.watch("left,top,width,height,display", function() { if (el.is(":visible")) $(this).shadow(opt); // redraw else sh.hide(); }, 100, "_shadowMove"); The code now monitors several properties and if any of them change the provided function is called. So when the target object is moved or hidden or resized the watcher function is called and the shadow can be redrawn or hidden in the case of visibility going away. So if you run any of the following code: $("#box") .shadow() .draggable({ handle: ".blockheader" }); // drag around the box - shadow should follow // hide the box - shadow should disappear with box setTimeout(function() { $("#box").hide(); }, 4000); // show the box - shadow should come back too setTimeout(function() { $("#box").show(); }, 8000); This can be very handy functionality when you're dealing with objects or operations that you need to track generically and there are no native events for them. For example, with a generic shadow object that attaches itself to any another element there's no way that I know of to track whether the object has been moved or hidden either via some UI operation (like dragging) or via code. While some UI operations like jQuery.ui.draggable would allow events to fire when the mouse is moved nothing of the sort exists if you modify locations in code. Even tracking the object in drag mode this is hardly generic behavior - a generic shadow implementation can't know when dragging is hooked up. So the watcher provides an alternative that basically gives an Observer like pattern that notifies you when something you're interested in changes. In the watcher hookup code (in the shadow() plugin) above  a check is made if the object is visible and if it is the shadow is redrawn. Otherwise the shadow is hidden. The first parameter is a list of CSS properties to be monitored followed by the function that is called. The function called receives this as the element that's been changed and receives two parameters: The array of watched objects with their current values, plus an index to the object that caused the change function to fire. How does it work When I wrote it about this last time I started out with a simple timer that would poll for changes at a fixed interval with setInterval(). A few folks commented that there are is a DOM API - DOMAttrmodified in Mozilla and propertychange in IE that allow notification whenever any property changes which is much more efficient and smooth than the setInterval approach I used previously. On browser that support these events (FireFox and IE basically - WebKit has the DOMAttrModified event but it doesn't appear to work) the shadow effect is instant - no 'drag behind' of the shadow. Running on a browser that doesn't support still uses setInterval() and the shadow movement is slightly delayed which looks sloppy. There are a few additional changes to this code - it also supports monitoring multiple CSS properties now so a single object can monitor a host of CSS properties rather than one object per property which is easier to work with. For display purposes position, bounds and visibility will be common properties that are to be watched. Here's what the new version looks like: $.fn.watch = function (props, func, interval, id) { /// <summary> /// Allows you to monitor changes in a specific /// CSS property of an element by polling the value. /// when the value changes a function is called. /// The function called is called in the context /// of the selected element (ie. this) /// </summary> /// <param name="prop" type="String">CSS Properties to watch sep. by commas</param> /// <param name="func" type="Function"> /// Function called when the value has changed. /// </param> /// <param name="interval" type="Number"> /// Optional interval for browsers that don't support DOMAttrModified or propertychange events. /// Determines the interval used for setInterval calls. /// </param> /// <param name="id" type="String">A unique ID that identifies this watch instance on this element</param> /// <returns type="jQuery" /> if (!interval) interval = 200; if (!id) id = "_watcher"; return this.each(function () { var _t = this; var el$ = $(this); var fnc = function () { __watcher.call(_t, id) }; var itId = null; var data = { id: id, props: props.split(","), func: func, vals: [props.split(",").length], fnc: fnc, origProps: props, interval: interval }; $.each(data.props, function (i) { data.vals[i] = el$.css(data.props[i]); }); el$.data(id, data); hookChange(el$, id, data.fnc); }); function hookChange(el$, id, fnc) { el$.each(function () { var el = $(this); if (typeof (el.get(0).onpropertychange) == "object") el.bind("propertychange." + id, fnc); else if ($.browser.mozilla) el.bind("DOMAttrModified." + id, fnc); else itId = setInterval(fnc, interval); }); } function __watcher(id) { var el$ = $(this); var w = el$.data(id); if (!w) return; var _t = this; if (!w.func) return; // must unbind or else unwanted recursion may occur el$.unwatch(id); var changed = false; var i = 0; for (i; i < w.props.length; i++) { var newVal = el$.css(w.props[i]); if (w.vals[i] != newVal) { w.vals[i] = newVal; changed = true; break; } } if (changed) w.func.call(_t, w, i); // rebind event hookChange(el$, id, w.fnc); } } $.fn.unwatch = function (id) { this.each(function () { var el = $(this); var fnc = el.data(id).fnc; try { if (typeof (this.onpropertychange) == "object") el.unbind("propertychange." + id, fnc); else if ($.browser.mozilla) el.unbind("DOMAttrModified." + id, fnc); else clearInterval(id); } // ignore if element was already unbound catch (e) { } }); return this; } There are basically two jQuery functions - watch and unwatch. jQuery.fn.watch(props,func,interval,id) Starts watching an element for changes in the properties specified. props The CSS properties that are to be watched for changes. If any of the specified properties changes the function specified in the second parameter is fired. func (watchData,index) The function fired in response to a changed property. Receives this as the element changed and object that represents the watched properties and their respective values. The first parameter is passed in this structure:    { id: itId, props: [], func: func, vals: [] }; A second parameter is the index of the changed property so data.props[i] or data.vals[i] gets the property value that has changed. interval The interval for setInterval() for those browsers that don't support property watching in the DOM. In milliseconds. id An optional id that identifies this watcher. Required only if multiple watchers might be hooked up to the same element. The default is _watcher if not specified. jQuery.fn.unwatch(id) Unhooks watching of the element by disconnecting the event handlers. id Optional watcher id that was specified in the call to watch. This value can be omitted to use the default value of _watcher. You can also grab the latest version of the  code for this plug-in as well as the shadow in the full library at: http://www.west-wind.com:8080/svn/jquery/trunk/jQueryControls/Resources/ww.jquery.js watcher has no other dependencies although it lives in this larger library. The shadow plug-in depends on watcher.© Rick Strahl, West Wind Technologies, 2005-2011

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  • C#: Handling Notifications: inheritance, events, or delegates?

    - by James Michael Hare
    Often times as developers we have to design a class where we get notification when certain things happen. In older object-oriented code this would often be implemented by overriding methods -- with events, delegates, and interfaces, however, we have far more elegant options. So, when should you use each of these methods and what are their strengths and weaknesses? Now, for the purposes of this article when I say notification, I'm just talking about ways for a class to let a user know that something has occurred. This can be through any programmatic means such as inheritance, events, delegates, etc. So let's build some context. I'm sitting here thinking about a provider neutral messaging layer for the place I work, and I got to the point where I needed to design the message subscriber which will receive messages from the message bus. Basically, what we want is to be able to create a message listener and have it be called whenever a new message arrives. Now, back before the flood we would have done this via inheritance and an abstract class: 1:  2: // using inheritance - omitting argument null checks and halt logic 3: public abstract class MessageListener 4: { 5: private ISubscriber _subscriber; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber) 11: { 12: _subscriber = subscriber; 13: _messageThread = new Thread(MessageLoop); 14: _messageThread.Start(); 15: } 16:  17: // user will override this to process their messages 18: protected abstract void OnMessageReceived(Message msg); 19:  20: // handle the looping in the thread 21: private void MessageLoop() 22: { 23: while(!_isHalted) 24: { 25: // as long as processing, wait 1 second for message 26: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 27: if(msg != null) 28: { 29: OnMessageReceived(msg); 30: } 31: } 32: } 33: ... 34: } It seems so odd to write this kind of code now. Does it feel odd to you? Maybe it's just because I've gotten so used to delegation that I really don't like the feel of this. To me it is akin to saying that if I want to drive my car I need to derive a new instance of it just to put myself in the driver's seat. And yet, unquestionably, five years ago I would have probably written the code as you see above. To me, inheritance is a flawed approach for notifications due to several reasons: Inheritance is one of the HIGHEST forms of coupling. You can't seal the listener class because it depends on sub-classing to work. Because C# does not allow multiple-inheritance, I've spent my one inheritance implementing this class. Every time you need to listen to a bus, you have to derive a class which leads to lots of trivial sub-classes. The act of consuming a message should be a separate responsibility than the act of listening for a message (SRP). Inheritance is such a strong statement (this IS-A that) that it should only be used in building type hierarchies and not for overriding use-specific behaviors and notifications. Chances are, if a class needs to be inherited to be used, it most likely is not designed as well as it could be in today's modern programming languages. So lets look at the other tools available to us for getting notified instead. Here's a few other choices to consider. Have the listener expose a MessageReceived event. Have the listener accept a new IMessageHandler interface instance. Have the listener accept an Action<Message> delegate. Really, all of these are different forms of delegation. Now, .NET events are a bit heavier than the other types of delegates in terms of run-time execution, but they are a great way to allow others using your class to subscribe to your events: 1: // using event - ommiting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private bool _isHalted = false; 6: private Thread _messageThread; 7:  8: // assign the subscriber and start the messaging loop 9: public MessageListener(ISubscriber subscriber) 10: { 11: _subscriber = subscriber; 12: _messageThread = new Thread(MessageLoop); 13: _messageThread.Start(); 14: } 15:  16: // user will override this to process their messages 17: public event Action<Message> MessageReceived; 18:  19: // handle the looping in the thread 20: private void MessageLoop() 21: { 22: while(!_isHalted) 23: { 24: // as long as processing, wait 1 second for message 25: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 26: if(msg != null && MessageReceived != null) 27: { 28: MessageReceived(msg); 29: } 30: } 31: } 32: } Note, now we can seal the class to avoid changes and the user just needs to provide a message handling method: 1: theListener.MessageReceived += CustomReceiveMethod; However, personally I don't think events hold up as well in this case because events are largely optional. To me, what is the point of a listener if you create one with no event listeners? So in my mind, use events when handling the notification is optional. So how about the delegation via interface? I personally like this method quite a bit. Basically what it does is similar to inheritance method mentioned first, but better because it makes it easy to split the part of the class that doesn't change (the base listener behavior) from the part that does change (the user-specified action after receiving a message). So assuming we had an interface like: 1: public interface IMessageHandler 2: { 3: void OnMessageReceived(Message receivedMessage); 4: } Our listener would look like this: 1: // using delegation via interface - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private IMessageHandler _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler.OnMessageReceived(msg); 28: } 29: } 30: } 31: } And they would call it by creating a class that implements IMessageHandler and pass that instance into the constructor of the listener. I like that this alleviates the issues of inheritance and essentially forces you to provide a handler (as opposed to events) on construction. Well, this is good, but personally I think we could go one step further. While I like this better than events or inheritance, it still forces you to implement a specific method name. What if that name collides? Furthermore if you have lots of these you end up either with large classes inheriting multiple interfaces to implement one method, or lots of small classes. Also, if you had one class that wanted to manage messages from two different subscribers differently, it wouldn't be able to because the interface can't be overloaded. This brings me to using delegates directly. In general, every time I think about creating an interface for something, and if that interface contains only one method, I start thinking a delegate is a better approach. Now, that said delegates don't accomplish everything an interface can. Obviously having the interface allows you to refer to the classes that implement the interface which can be very handy. In this case, though, really all you want is a method to handle the messages. So let's look at a method delegate: 1: // using delegation via delegate - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler(msg); 28: } 29: } 30: } 31: } Here the MessageListener now takes an Action<Message>.  For those of you unfamiliar with the pre-defined delegate types in .NET, that is a method with the signature: void SomeMethodName(Message). The great thing about delegates is it gives you a lot of power. You could create an anonymous delegate, a lambda, or specify any other method as long as it satisfies the Action<Message> signature. This way, you don't need to define an arbitrary helper class or name the method a specific thing. Incidentally, we could combine both the interface and delegate approach to allow maximum flexibility. Doing this, the user could either pass in a delegate, or specify a delegate interface: 1: // using delegation - give users choice of interface or delegate 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // passes the interface method as a delegate using method group 19: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 20: : this(subscriber, handler.OnMessageReceived) 21: { 22: } 23:  24: // handle the looping in the thread 25: private void MessageLoop() 26: { 27: while(!_isHalted) 28: { 29: // as long as processing, wait 1 second for message 30: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 31: if(msg != null) 32: { 33: _handler(msg); 34: } 35: } 36: } 37: } } This is the method I tend to prefer because it allows the user of the class to choose which method works best for them. You may be curious about the actual performance of these different methods. 1: Enter iterations: 2: 1000000 3:  4: Inheritance took 4 ms. 5: Events took 7 ms. 6: Interface delegation took 4 ms. 7: Lambda delegate took 5 ms. Before you get too caught up in the numbers, however, keep in mind that this is performance over over 1,000,000 iterations. Since they are all < 10 ms which boils down to fractions of a micro-second per iteration so really any of them are a fine choice performance wise. As such, I think the choice of what to do really boils down to what you're trying to do. Here's my guidelines: Inheritance should be used only when defining a collection of related types with implementation specific behaviors, it should not be used as a hook for users to add their own functionality. Events should be used when subscription is optional or multi-cast is desired. Interface delegation should be used when you wish to refer to implementing classes by the interface type or if the type requires several methods to be implemented. Delegate method delegation should be used when you only need to provide one method and do not need to refer to implementers by the interface name.

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  • The Return Of __FILE__ And __LINE__ In .NET 4.5

    - by Alois Kraus
    Good things are hard to kill. One of the most useful predefined compiler macros in C/C++ were __FILE__ and __LINE__ which do expand to the compilation units file name and line number where this value is encountered by the compiler. After 4.5 versions of .NET we are on par with C/C++ again. It is of course not a simple compiler expandable macro it is an attribute but it does serve exactly the same purpose. Now we do get CallerLineNumberAttribute  == __LINE__ CallerFilePathAttribute        == __FILE__ CallerMemberNameAttribute  == __FUNCTION__ (MSVC Extension)   The most important one is CallerMemberNameAttribute which is very useful to implement the INotifyPropertyChanged interface without the need to hard code the name of the property anymore. Now you can simply decorate your change method with the new CallerMemberName attribute and you get the property name as string directly inserted by the C# compiler at compile time.   public string UserName { get { return _userName; } set { _userName=value; RaisePropertyChanged(); // no more RaisePropertyChanged(“UserName”)! } } protected void RaisePropertyChanged([CallerMemberName] string member = "") { var copy = PropertyChanged; if(copy != null) { copy(new PropertyChangedEventArgs(this, member)); } } Nice and handy. This was obviously the prime reason to implement this feature in the C# 5.0 compiler. You can repurpose this feature for tracing to get your hands on the method name of your caller along other stuff very fast now. All infos are added during compile time which is much faster than other approaches like walking the stack. The example on MSDN shows the usage of this attribute with an example public static void TraceMessage(string message, [CallerMemberName] string memberName = "", [CallerFilePath] string sourceFilePath = "", [CallerLineNumber] int sourceLineNumber = 0) { Console.WriteLine("Hi {0} {1} {2}({3})", message, memberName, sourceFilePath, sourceLineNumber); }   When I do think of tracing I do usually want to have a API which allows me to Trace method enter and leave Trace messages with a severity like Info, Warning, Error When I do print a trace message it is very useful to print out method and type name as well. So your API must either be able to pass the method and type name as strings or extract it automatically via walking back one Stackframe and fetch the infos from there. The first glaring deficiency is that there is no CallerTypeAttribute yet because the C# compiler team was not satisfied with its performance.   A usable Trace Api might therefore look like   enum TraceTypes { None = 0, EnterLeave = 1 << 0, Info = 1 << 1, Warn = 1 << 2, Error = 1 << 3 } class Tracer : IDisposable { string Type; string Method; public Tracer(string type, string method) { Type = type; Method = method; if (IsEnabled(TraceTypes.EnterLeave,Type, Method)) { } } private bool IsEnabled(TraceTypes traceTypes, string Type, string Method) { // Do checking here if tracing is enabled return false; } public void Info(string fmt, params object[] args) { } public void Warn(string fmt, params object[] args) { } public void Error(string fmt, params object[] args) { } public static void Info(string type, string method, string fmt, params object[] args) { } public static void Warn(string type, string method, string fmt, params object[] args) { } public static void Error(string type, string method, string fmt, params object[] args) { } public void Dispose() { // trace method leave } } This minimal trace API is very fast but hard to maintain since you need to pass in the type and method name as hard coded strings which can change from time to time. But now we have at least CallerMemberName to rid of the explicit method parameter right? Not really. Since any acceptable usable trace Api should have a method signature like Tracexxx(… string fmt, params [] object args) we not able to add additional optional parameters after the args array. If we would put it before the format string we would need to make it optional as well which would mean the compiler would need to figure out what our trace message and arguments are (not likely) or we would need to specify everything explicitly just like before . There are ways around this by providing a myriad of overloads which in the end are routed to the very same method but that is ugly. I am not sure if nobody inside MS agrees that the above API is reasonable to have or (more likely) that the whole talk about you can use this feature for diagnostic purposes was not a core feature at all but a simple byproduct of making the life of INotifyPropertyChanged implementers easier. A way around this would be to allow for variable argument arrays after the params keyword another set of optional arguments which are always filled by the compiler but I do not know if this is an easy one. The thing I am missing much more is the not provided CallerType attribute. But not in the way you would think of. In the API above I did add some filtering based on method and type to stay as fast as possible for types where tracing is not enabled at all. It should be no more expensive than an additional method call and a bool variable check if tracing for this type is enabled at all. The data is tightly bound to the calling type and method and should therefore become part of the static type instance. Since extending the CLR type system for tracing is not something I do expect to happen I have come up with an alternative approach which allows me basically to attach run time data to any existing type object in super fast way. The key to success is the usage of generics.   class Tracer<T> : IDisposable { string Method; public Tracer(string method) { if (TraceData<T>.Instance.Enabled.HasFlag(TraceTypes.EnterLeave)) { } } public void Dispose() { if (TraceData<T>.Instance.Enabled.HasFlag(TraceTypes.EnterLeave)) { } } public static void Info(string fmt, params object[] args) { } /// <summary> /// Every type gets its own instance with a fresh set of variables to describe the /// current filter status. /// </summary> /// <typeparam name="T"></typeparam> internal class TraceData<UsingType> { internal static TraceData<UsingType> Instance = new TraceData<UsingType>(); public bool IsInitialized = false; // flag if we need to reinit the trace data in case of reconfigured trace settings at runtime public TraceTypes Enabled = TraceTypes.None; // Enabled trace levels for this type } } We do not need to pass the type as string or Type object to the trace Api. Instead we define a generic Api that accepts the using type as generic parameter. Then we can create a TraceData static instance which is due to the nature of generics a fresh instance for every new type parameter. My tests on my home machine have shown that this approach is as fast as a simple bool flag check. If you have an application with many types using tracing you do not want to bring the app down by simply enabling tracing for one special rarely used type. The trace filter performance for the types which are not enabled must be therefore the fasted code path. This approach has the nice side effect that if you store the TraceData instances in one global list you can reconfigure tracing at runtime safely by simply setting the IsInitialized flag to false. A similar effect can be achieved with a global static Dictionary<Type,TraceData> object but big hash tables have random memory access semantics which is bad for cache locality and you always need to pay for the lookup which involves hash code generation, equality check and an indexed array access. The generic version is wicked fast and allows you to add more features to your tracing Api with minimal perf overhead. But it is cumbersome to write the generic type argument always explicitly and worse if you do refactor code and move parts of it to other classes it might be that you cannot configure tracing correctly. I would like therefore to decorate my type with an attribute [CallerType] class Tracer<T> : IDisposable to tell the compiler to fill in the generic type argument automatically. class Program { static void Main(string[] args) { using (var t = new Tracer()) // equivalent to new Tracer<Program>() { That would be really useful and super fast since you do not need to pass any type object around but you do have full type infos at hand. This change would be breaking if another non generic type exists in the same namespace where now the generic counterpart would be preferred. But this is an acceptable risk in my opinion since you can today already get conflicts if two generic types of the same name are defined in different namespaces. This would be only a variation of this issue. When you do think about this further you can add more features like to trace the exception in your Dispose method if the method is left with an exception with that little trick I did write some time ago. You can think of tracing as a super fast and configurable switch to write data to an output destination or to execute alternative actions. With such an infrastructure you can e.g. Reconfigure tracing at run time. Take a memory dump when a specific method is left with a specific exception. Throw an exception when a specific trace statement is hit (useful for testing error conditions). Execute a passed delegate which e.g. dumps additional state when enabled. Write data to an in memory ring buffer and dump it when specific events do occur (e.g. method is left with an exception, triggered from outside). Write data to an output device. …. This stuff is really useful to have when your code is in production on a mission critical server and you need to find the root cause of sporadic crashes of your application. It could be a buggy graphics card driver which throws access violations into your application (ok with .NET 4 not anymore except if you enable a compatibility flag) where you would like to have a minidump or you have reached after two weeks of operation a state where you need a full memory dump at a specific point in time in the middle of an transaction. At my older machine I do get with this super fast approach 50 million traces/s when tracing is disabled. When I do know that tracing is enabled for this type I can walk the stack by using StackFrameHelper.GetStackFramesInternal to check further if a specific action or output device is configured for this method which is about 2-3 times faster than the regular StackTrace class. Even with one String.Format I am down to 3 million traces/s so performance is not so important anymore since I do want to do something now. The CallerMemberName feature of the C# 5 compiler is nice but I would have preferred to get direct access to the MethodHandle and not to the stringified version of it. But I really would like to see a CallerType attribute implemented to fill in the generic type argument of the call site to augment the static CLR type data with run time data.

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  • Does JUnit4 testclasses require a public no arg constructor?

    - by Thomas Baun
    I have a test class, written in JUnit4 syntax, that can be run in eclipse with the "run as junit test" option without failing. When I run the same test via an ant target I get this error: java.lang.Exception: Test class should have public zero-argument constructor at org.junit.internal.runners.MethodValidator.validateNoArgConstructor(MethodValidator.java:54) at org.junit.internal.runners.MethodValidator.validateAllMethods(MethodValidator.java:39) at org.junit.internal.runners.TestClassRunner.validate(TestClassRunner.java:33) at org.junit.internal.runners.TestClassRunner.<init>(TestClassRunner.java:27) at org.junit.internal.runners.TestClassRunner.<init>(TestClassRunner.java:20) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:26) at junit.framework.JUnit4TestAdapter.<init>(JUnit4TestAdapter.java:24) at junit.framework.JUnit4TestAdapter.<init>(JUnit4TestAdapter.java:17) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.run(JUnitTestRunner.java:386) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.launch(JUnitTestRunner.java:911) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.main(JUnitTestRunner.java:768) Caused by: java.lang.NoSuchMethodException: dk.gensam.gaia.business.bonusregulering.TestBonusregulerAftale$Test1Reader.<init>() at java.lang.Class.getConstructor0(Class.java:2706) at java.lang.Class.getConstructor(Class.java:1657) at org.junit.internal.runners.MethodValidator.validateNoArgConstructor(MethodValidator.java:52) I have no public no arg constructor in the class, but is this really necessary? This is my ant target <target name="junit" description="Execute unit tests" depends="compile, jar-test"> <delete dir="tmp/rawtestoutput"/> <delete dir="test-reports"/> <mkdir dir="tmp/rawtestoutput"/> <junit printsummary="true" failureproperty="junit.failure" fork="true"> <classpath refid="class.path.test"/> <classpath refid="class.path.model"/> <classpath refid="class.path.gui"/> <classpath refid="class.path.jfreereport"/> <classpath path="tmp/${test.jar}"></classpath> <batchtest todir="tmp/rawtestoutput"> <fileset dir="${build}/test"> <include name="**/*Test.class" /> <include name="**/Test*.class" /> </fileset> </batchtest> </junit> <junitreport todir="tmp"> <fileset dir="tmp/rawtestoutput"/> <report todir="test-reports"/> </junitreport> <fail if="junit. failure" message="Unit test(s) failed. See reports!"/> </target> The test class have no constructors, but it has an inner class with default modifier. It also have an anonymouse inner class. Both inner classes gives the "Test class should have public zero-argument constructor error". I am using Ant version 1.7.1 and JUnit 4.7

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  • How to set incremental CSS classes in each Table Cell with jQuery?

    - by Mark Rapp
    I have a table populated via a DB and it renders like so (it could have any number of columns referring to "time", 5 columns, 8 columns, 2 columns, etc): <table id="eventInfo"> <tr> <td class="name">John</td> <td class="date">Dec 20</td> <td class="**time**">2pm</td> <td class="**time**">3pm</td> <td class="**time**">4pm</td> <td class="event">Birthday</td> </tr> <tr> <td class="name">Billy</td> <td class="date">Dec 19</td> <td class="**time**">6pm</td> <td class="**time**">7pm</td> <td class="**time**">8pm</td> <td class="event">Birthday</td> </tr> With jQuery, I'd like to go through each Table Row and incrementally set an additional class-name on only the Table Cells where "class='time'" so that the result would be: John Dec 20 2pm 3pm 4pm Birthday Billy Dec 19 6pm 7pm 8pm Birthday I've only been able to get it to count all of the Table Cells where "class='time'" and not each set within its own Table Row. This is what I've tried with jQuery: $(document).ready(function() { $("table#eventInfo tr").each(function() { var tcount = 0; $("td.time").attr("class", function() { return "timenum-" + tcount++; }) //writes out the results in each TD .each(function() { $("span", this).html("(class = '<b>" + this.className + "</b>')"); }); }); }); Unfortunately, this only results in: <table id="eventInfo"> <tr> <td class="name">John</td> <td class="date">Dec 20</td> <td class="**time** **timenum-1**">2pm</td> <td class="**time** **timenum-2**">3pm</td> <td class="**time** **timenum-3**">4pm</td> <td class="event">Birthday</td> </tr> <tr> <td class="name">Billy</td> <td class="date">Dec 19</td> <td class="**time** **timenum-4**">6pm</td> <td class="**time** **timenum-5**">7pm</td> <td class="**time** **timenum-6**">8pm</td> <td class="event">Birthday</td> </tr> Thanks for your help!

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  • WPF TreeView similar to Organizational chart with connecting lines

    - by Priya
    I have modified my treeview to look like an Org chart using the example shown in the Code Project website (Author Josh Smith). I need connecting lines in the treeview to make it look exact to org chart. I found references pointing to the below site http://wpfblog.info/2008/05/26/turning-a-treeview-into-an-org-chart-with-connectors/ But I am not able to view the content. Probably the webpage has been moved. Can anybody help?

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  • Binding to a dictionary in Silverlight with INotifyPropertyChanged

    - by rip
    In silverlight, I can not get INotifyPropertyChanged to work like I want it to when binding to a dictionary. In the example below, the page binds to the dictionary okay but when I change the content of one of the textboxes the CustomProperties property setter is not called. The CustomProperties property setter is only called when CustomProperties is set and not when the values within it are set. I am trying to do some validation on the dictionary values and so am looking to run some code when each value within the dictionary is changed. Is there anything I can do here? C# public partial class MainPage : UserControl { public MainPage() { InitializeComponent(); MyEntity ent = new MyEntity(); ent.CustomProperties.Add("Title", "Mr"); ent.CustomProperties.Add("FirstName", "John"); ent.CustomProperties.Add("Name", "Smith"); this.DataContext = ent; } } public class MyEntity : INotifyPropertyChanged { public event PropertyChangedEventHandler System.ComponentModel.INotifyPropertyChanged.PropertyChanged; public delegate void PropertyChangedEventHandler(object sender, System.ComponentModel.PropertyChangedEventArgs e); private Dictionary<string, object> _customProps; public Dictionary<string, object> CustomProperties { get { if (_customProps == null) { _customProps = new Dictionary<string, object>(); } return _customProps; } set { _customProps = value; if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs("CustomProperties")); } } } } VB Partial Public Class MainPage Inherits UserControl Public Sub New() InitializeComponent() Dim ent As New MyEntity ent.CustomProperties.Add("Title", "Mr") ent.CustomProperties.Add("FirstName", "John") ent.CustomProperties.Add("Name", "Smith") Me.DataContext = ent End Sub End Class Public Class MyEntity Implements INotifyPropertyChanged Public Event PropertyChanged(ByVal sender As Object, ByVal e As System.ComponentModel.PropertyChangedEventArgs) Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged Private _customProps As Dictionary(Of String, Object) Public Property CustomProperties As Dictionary(Of String, Object) Get If _customProps Is Nothing Then _customProps = New Dictionary(Of String, Object) End If Return _customProps End Get Set(ByVal value As Dictionary(Of String, Object)) _customProps = value RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs("CustomProperties")) End Set End Property End Class Xaml <TextBox Height="23" Name="TextBox1" Text="{Binding Path=CustomProperties[Title], Mode=TwoWay}" /> <TextBox Height="23" Name="TextBox2" Text="{Binding Path=CustomProperties[FirstName], Mode=TwoWay}" /> <TextBox Height="23" Name="TextBox3" Text="{Binding Path=CustomProperties[Name], Mode=TwoWay}" />

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  • Comparing strings with user-created string class

    - by meepz
    Basically, I created my own string class, mystring.h and mystring.c. What I want to do is write a function that compares two "strings" and then returns 1 first word is larger than the second, the opposite if word 2 is larger than word 1, and 0 if the two words are equal. What I have so far is this: int compareto(void * S1, void * S2){ String s1 = (String S1); String s2 = (String S2); int i, cs1 = 0, cs2 = 0; //cs1 is count of s1, cs2 is count of s2 while(s1->c[i] != '\0'){ //basically, while there is a word if(s1->c[i] < s2->c[i]) // if string 1 char is less than string 2 char cs2++; //add to string 2 count else (s1->c[i] > s2->c[i]) //vice versa cs1++; i++; } for my return I basically have if(cs1>cs2){ return 1; } else if(cs2 > cs1){ return 2; } return 0; here is mystring.h typedef struct mystring { char * c; int length; int (*sLength)(void * s); char (*charAt)(void * s, int i); int (*compareTo)(void * s1, void * s2); struct mystring * (*concat)(void * s1, void * s2); struct mystring * (*subString)(void * s, int begin, int end); void (*printS)(void * s); } string_t; typedef string_t * String; This does what I want, but only for unspecified order. What I want to do is search through my linked list for the last name. Ex. I have two entries in my linked list, smith and jones; Jones will be output as greater than smith, but alphabetically it isnt. (I'm using this to remove student entries from a generic link list I created) Any suggestions, all of my google searches involve using the library, so I've had no luck)

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  • LINQ to SQL: To Attach or Not To Attach

    - by bradhe
    So I'm have a really hard time figuring out when I should be attaching to an object and when I shouldn't be attaching to an object. First thing's first, here is a small diagram of my (very simplified) object model. Edit: Okay, apparently I'm not allowed to post images...here you go: http://i.imgur.com/2ROFI.png In my DAL I create a new DataContext every time I do a data-related operation. Say, for instance, I want to save a new user. In my business layer I create a new user. var user = new User(); user.FirstName = "Bob"; user.LastName = "Smith"; user.Username = "bob.smith"; user.Password = StringUtilities.EncodePassword("MyPassword123"); user.Organization = someOrganization; // Assume that someOrganization was loaded and it's data context has been garbage collected. Now I want to go save this user. var userRepository = new RepositoryFactory.GetRepository<UserRepository>(); userRepository.Save(user); Neato! Here is my save logic: public void Save(User user) { if (!DataContext.Users.Contains(user)) { user.Id = Guid.NewGuid(); user.CreatedDate = DateTime.Now; user.Disabled = false; //DataContext.Organizations.Attach(user.Organization); DataContext.Users.InsertOnSubmit(user); } else { DataContext.Users.Attach(user); } DataContext.SubmitChanges(); // Finished here as well. user.Detach(); } So, here we are. You'll notice that I comment out the bit where the DataContext attachs to the organization. If I attach to the organization I get the following exception: NotSupportedException: An attempt has been made to Attach or Add an entity that is not new, perhaps having been loaded from another DataContext. This is not supported. Hmm, that doesn't work. Let me try it without attaching (i.e. comment out that line about attaching to the organization). DuplicateKeyException: Cannot add an entity with a key that is already in use. WHAAAAT? I can only assume this is trying to insert a new organization which is obviously false. So, what's the deal guys? What should I do? What is the proper approach? It seems like L2S makes this quite a bit harder than it should be...

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  • Facebook - finding users by name

    - by Gublooo
    Hello Guys, I'm very new to facebook and wanted to know if this is even possible to do with facebook API. If a user searches for a name on my website - say "Jamie Smith" - I want to pass this name to facebook and find all users that match that name - so if I can get back their photo and name to display on my site - so users can identify the right person. I'm using PHP so if there's any example or link that you can provide will be really helpful. Thanks

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  • What's the best Open Php newsletter manager ?

    - by Bilel
    Hi :) I'm looking for a nice newsletter management solution. I tried CCmail a good script but whaere I can't imort usernames !!! I would like to find a system that is able to import Opt-in lists in the following format : John Smith;[email protected];other paramaeters...;[like] ;Male;Age... I will develop my own module if I could find another emailing manager Are you already satisfied with a similar application with a trusted (spam-prevention) emailer ? Thank you :)

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  • Source for Names to use in web scraping

    - by PyNEwbie
    Can anyone suggest a good source of names that I can use to help analyze some tables on web pages. The first column of the tables I am scraping have names alone, names and titles or just titles. The names can be as varied as John Smith to Vikram Saksena. I have been poking around for a compiled list of words that can be found in proper names.

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  • sorting two tables (full join)

    - by Ruslan
    i'm joining tables like: select * from tableA a full join tableB b on a.id = b.id But the output should be: row without null fields row with null fields in tableB row with null fields in tableA Like: a.id a.name b.id b.name 5 Peter 5 Jones 2 Steven 2 Pareker 6 Paul null null 4 Ivan null null null null 1 Smith null null 3 Parker

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  • Capitalization of Person names in programming

    - by Albert
    Hey all, Is anyone aware of some code/rules on how to capitalize the names of people correctly? John Smith Johan van Rensburg Derrick von Gogh Ruby de La Fuente Peter Maclaurin Garry McDonald (these may not be correct, just some sample names and how the capitalization could be/work) This seems like a losing battle... If anyone has some code or rules on when and how to capitalize names, let me know :) Cheers, Albert

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  • Clarification How CRF(Conditional random Field) works using examples

    - by Moges.A
    I read different documents how CRF(conditional random field) works but all the papers puts the formula only. Is there any one who can send me a paper that describes about CRF with examples like if we have a sentence "Mr.Smith was born in New York. He has been working for the last 20 years in Microsoft company." if the above sentence is given as an input to train, how does the Model works during the training taking in to consideration for the formula for CRF? Moges.A

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  • When to address managed heap fragmentation

    - by emddudley
    I was reading a blog entry by Josh Smith where he used a cache mechanism in order to "reduce managed heap fragmentation". His caching reduces the number of short-lived objects being created at the cost of slightly slower execution speed. How much of a problem is managed heap fragmentation in a managed language like C#? How can you diagnose if it's an issue? In what situations would you typically need to address it?

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  • In MVVM should the ViewModel or Model implement INotifyPropertyChanged?

    - by Edward Tanguay
    Most MVVM examples I have worked through have had the Model implement INotifyPropertyChanged, but in Josh Smith's CommandSink example the ViewModel implements INotifyPropertyChanged. I'm still cognitively putting together the MVVM concepts, so I don't know if: you have to put the INotifyPropertyChanged in the ViewModel to get CommandSink to work this is just an aberration of the norm and it doesn't really matter you should always have the Model implement INotifyPropertyChanged and this is just a mistake which would be corrected if this were developed from a code example to an application What have been others' experiences on MVVM projects you have worked on?

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