Search Results

Search found 11640 results on 466 pages for 'figure'.

Page 33/466 | < Previous Page | 29 30 31 32 33 34 35 36 37 38 39 40  | Next Page >

  • GuestPost: Announcing gmStudio V9.85 for VB6/ASP/COM re-engineering

    - by Eric Nelson
    Mark Juras of GreatMigrations.com kindly sent me an article on gmStudio which I have posted on my old VB focused goto100 site. gmStudio is a programmable VB6/ASP/COM re-engineering tool that enables an agile tool-assisted rewrite methodology and helps teams dramatically lower the total cost, risk, and disruption of ambitious migration projects without sacrificing quality, control, or time to market. You can find the rest of the article over on goto100. Figure 1: the gmStudio Main Form

    Read the article

  • Ubuntu LiveCD/USB image that boots directly to low graphics desktop

    - by user14146
    I use Ubuntu as a diagnostic tool sometimes, and it would be great to get a modification that lets you boot directly to the LiveCD desktop, preferably with the special effects dialed down. Is there such a tool? Unetbootin doesn't seem to let you do this, and Remastersys could probably do this, but I'd have to dig into the code quite a bit and figure out what to remove, which I can do, but I figured someone might have already done this and would save me the trouble.

    Read the article

  • Why would someone want to take over control of my domain name?

    - by mike jones
    I was approached by a person wanting to help me set up a website. In order to do this he has requested that I allow him to transfer my domain name to his account, for easier management. I would retain the right of usage and he would pay the bill for maintaining the name. This sounds fishy, but I can't figure out what he hopes to gain if this is a scam. Is this a common practice among 'Administrative Contacts'?

    Read the article

  • Turn off the navigation menus on a MojoPortal page

    - by strongeye
    I needed to figure out how to turn off the navigation for the portal from my custom module. After some searching, I found code in Secure/Login.aspx.cs that did the trick. The function to use is this: SuppressAllMenus() This function is part of MojoPortal.Web.mojoBasePage so pages that inherit from that will already have access to the function.

    Read the article

  • Changing screen saver settings without completely removing gnome-screensaver and installing xscreensaver

    - by Sam
    I am on 11.04 atm. Would like to figure out how to change the settings for screensavers without completely switching to xscreensaver. I read somewhere that it doesn't play as nicely with some of gnome's features like screen locking. I also read some guide that recommended installing xscreensaver and configuring your screen saver settings there and apparently they were supposed to be used by gnome-screensaver as well. But that did not work for me. gnome-screensaver sure sucks

    Read the article

  • Ord function implementation in Delphi

    - by Federico Zancan
    Purely as an exercise at home, aimed to better understand some language basics, I tried to reimplement the Ord function, but I came across a problem. In fact, the existing Ord function can accept arguments of a variety of different types (AnsiChar, Char, WideChar, Enumeration, Integer, Int64) and can return Integer or Int64. I can't figure out how to declare multiple versions of the same function. How should this be coded in Delphi?

    Read the article

  • Shadow mapping: what is the light looking at?

    - by PgrAm
    I'm all set to set up shadow mapping in my 3d engine but there is one thing I am struggling to understand. The scene needs to be rendered from the light's point of view so I simply first move my camera to the light's position but then I need to find out which direction the light is looking. Since its a point light its not shining in any particular direction. How do I figure out what the orientation for the light point of view is?

    Read the article

  • Enabling unattended-upgrades from a shell script

    - by Grant Watson
    I have a shell script to automatically configure new Ubuntu virtual machines for my purposes. I would like this script to install and enable unattended-upgrades, but I cannot figure out how to do so without user interaction. The usual way to enable upgrades is dpkg-reconfigure unattended-upgrades, but of course that is interactive. The noninteractive front end avoids asking any questions at all, and the text front end seems bound and determined to do its I/O with the tty and not with stdin/stdout.

    Read the article

  • Ada Lovelace Day &amp;#8211; My Heroines

    <b>Sulamita Garcia:</b> "I have many heroes that inspired me to go ahead. Valorie Aurora, Telsa Gwynne, Pia Waugh, Akkanna Peck, Carla Schroeder, so many... but today I would like to talk about two women, who were the most inspiring for me from the beginning. One is a historical figure, other you may not know."

    Read the article

  • Ubuntu 10.10 forgets desktop theme.

    - by Marcelo Cantos
    (I posed this question on superuser.com and haven't received any answers or comments, then I came across this site, so my apologies to anyone who has seen this already.) I am running Ubuntu in VirtualBox (on a Windows 7 host). Several times now, the top-level menu bar, the task bar — and seemingly every system dialog — have forgotten the out-of-the-box "Ambiance" theme they conform to when I first installed the system. Window captions still preserve the theme, but pretty much nothing else does. I have searched high and low on Google for assistance with this problem. Everything I've found suggests either running some gconf reset or deleting .gconf* .gnome* and other similar directories. I have followed all this advice and nothing works. I still get a boring Windows-95-style gray 3D look and feel. On previous occasions, after much messing around I've given up and rebooted the VM instance, and been pleasantly suprised to see the original "Ambience" theme restored throughout the UI, but invariably it disappears again some time later, usually after a reboot, so I can never figure out what I did that broke it. Here's a sample from Ubuntu's site of what I want it to look like. And here's a screenshot of my system as it currently looks. Also note that my GNOME Terminals normally have a nice purple semi-translucent look, and as can be seen from the screenshot, they are now just a solid matt white. This last time (just yesterday), trying numerous combinations all the usual tricks and rebooting several times hasn't fixed it, so here I am on SU wondering: How do I recover the out-of-the-box theme for my Gnome/Ubuntu desktop, noting that blowing away all config files — as suggested in many places online — fails to achieve this? It might help to know that it seems to fail either after I resize the VM instance, forcing the Ubuntu desktop to resize itself, or after I play around with Compiz settings. I haven't been able to figure out which of these it is, and it could be neither. Given the amount of pain I have had to go through to get things back to normal (and given that I am at a loss as to how to do so), it has proven difficult to definitively isolate the cause.

    Read the article

  • totem doesn't enables you to skip forward or backward in a mp3

    - by user53058
    Can anyone help me figure this out? So if i open mp3 files in Totem: and Banshee 2.4 So for my main music player I use Banshee 2.4, which works pretty well, despite a few occasional hiccups (any suggestions as to something better are totally welcome) but when I'm downloading new mp3s to my desktop and I want to check them out I normally just click on them and have them open in Totem. ubuntu 11.04 x64

    Read the article

  • How can I find out if my domain has been added to email blacklists?

    - by Rob Sobers
    We do a lot of mass emailing of our contacts to promote events, send out newsletters, etc. Some people read and react, some people unsubscribe, but I fear that some might actually mark the email as spam. Is there any way to figure out whether my domain has been added to email blacklists or spam registries? Also, if I use a service like MailChimp to send the emails, how would this work? If one unscrupulous customer was using MailChimp for evil, wouldn't it affect all of their customers?

    Read the article

  • How do I configure sound with PulseAudio and Multiseat?

    - by Anthony
    In the spirit of full disclosure, i just posted this question to the ubuntu forums, but i figure more heads working on it couldn't hurt. I have a multi-seat setup working quite well. Hot plugging input devices works as expected and such. The only issue I am still not able to resolve is getting the audio for each seat. Here is a summary of my attempts at getting audio to work: Make ~/.pulse/default.pa dynamically configured based on which $DISPLAY the user logs in at. See this pastebin for the details. Load pulseaudio as a system-wide instance. Couldn't get this to work. None of the audio hardware was accessible to the users. Use udev rules to mark seats in ConsoleKit. Following udev guidelines found here: http://www.freedesktop.org/wiki/Software/systemd/multiseat I didn't think this would work, although it was "guaranteed" to work by someone in irc.freenode #pulseaudio None of those attempts yielded success, which is why I now turn to the community for help. It is quite possible that the suggested methods work and I just messed some aspect of it up, idk. This is the last piece of the puzzle which is needed before I can go and update the MultiseatX page to include instructions for Ubuntu 12.04. My understandings on the situation: Access to pulseaudio is restricted to the active session as marked by ConsoleKit (something about an ACL). CK can only mark one session as active at a time. This simple little fact of life leads me to believe that the solution should involve pulseaudio being run as a system-wide instance. Each user should connect to the pulse server and be limited to a subset of all the hardware. Maybe each user connects to the pulse server via localhost, idk. I do know that regardless of my attempts and their failed results, I was always able to use sudo aplay -D plughw:0,0 /usr/share/sounds/alsa/Front_Center.wav to play something to any of the hardware. I'm grasping at straws and am now down to the last few hairs i can pull out of my head. Please, help me figure this out so we can share the wealth. Any additional information needed will be provided at your request.

    Read the article

  • Marketing: Angry Birds - How it's done

    - by John
    Why do some apps, like Angry Birds, dominate the market while other cool/fun/addicting apps are never heard of? I'm trying to figure out the best marketing strategy, or best way to sell an app to mass market. Does anybody have any ideas or things they noticed about the marketing of major blockbuster apps, like Angry Birds, why they get so popular and stay at the top of charts. Thanks for any ideas, comments ...

    Read the article

  • Practicing Java Swing

    - by user1265125
    I've been learning Java by myself through many different online and offline resources. I just finished some basic practice and theoretical knowledge of Swing. Now, to become good at it I need some practice problems which would test my Swing skills, including GUI Building, listeners etc. But I can't figure out where to find such questions/problems for my practice. Do you guys know of an online resource? Some book would also do...

    Read the article

  • Ubuntu One and iPad

    - by Martin G Miller
    I have installed the Ubuntu One app for my iPad 3 running iOS 6. It runs and asked to access my pictures folder on the iPad, which I granted. Now it just displays a splash screen for the Ubuntu One but does not seem to be doing anything else. I can't figure out how to get it to see my regular Ubuntu One account that I have had for the last few years and use regularly between various Ubuntu computers I have.

    Read the article

  • String contains trailing zeroes when converted from decimal [migrated]

    - by Locke
    I've run into an unusual quirk in a program I'm writing, and I was trying to figure out if anyone knew the cause. Note that fixing the issue is easy enough. I just can't figure out why it is happening in the first place. I have a WinForms program written in VB.NET that is displaying a subset of data. It contains a few labels that show numeric values (the .Text property of the labels are being assigned directly from the Decimal values). These numbers are being returned by a DLL I wrote in C#. The DLL calls a webservice which initially returns the values in question. It returns one as a string, the other as a decimal (I don't have any control over the webservice, I just consume it). The DLL assigns these to properties on an object (both of which are decimals) then returns that object back to the WinForm program that called the DLL. Obviously, there's a lot of other data being consumed from the webservice, but no other operations are happening which could modify these properties. So, the short version is: WinForm requests a new Foo from the DLL. DLL creates object Foo. DLL calls webservice, which returns SomeOtherFoo. //Both Foo.Bar1 and Foo.Bar2 are decimals Foo.Bar1 = decimal.Parse(SomeOtherFoo.Bar1); //SomeOtherFoo.Bar1 is a string equal to "2.9000" Foo.Bar2 = SomeOtherFoo.Bar2; //SomeOtherFoo.Bar2 is a decimal equal to 2.9D DLL returns Foo to WinForm. WinForm.lblMockLabelName1.Text = Foo.Bar1 //Inspecting Foo.Bar1 indicates my value is 2.9D WinForm.lblMockLabelName2.Text = Foo.Bar2 //Inspecting Foo.Bar2 also indicates I'm 2.9D So, what's the quirk? WinForm.lblMockLabelName1.Text displays as "2.9000", whereas WinForm.lblMockLabelname2.Text displays as "2.9". Now, everything I know about C# and VB indicates that the format of the string which was initially parsed into the decimal should have no bearing on the outcome of a later decimal.ToString() operation called on the same decimal. I would expect that decimal.Parse(someDecimalString).ToString() would return the string without any trailing zeroes. Everything I find online seems to corroborate this (there are countless Stack Overflow questions asking exactly the opposite...how to keep the formatting from the initial parsing). At the moment, I've just removed the trailing zeroes from the initial string that gets parsed, which has hidden the quirk. However, I'd love to know why it happens in the first place.

    Read the article

  • How to adjust Skype webcam resolution

    - by Felix Elnan
    I have finally gotten my webcam (philips spc 300nc) working in Skype, and i thought i was all set. But the resolution is to low (176x144) so it zoomz in on the side of my face. I downloaded guvcview and set the resolution to 352x288 and it showed perfectly, until i tried to start the webcam in Skype, beacause there it stil was in 176x144. I cant really figure out why. I preload skype with v4l2convert.so and the webcam works great in both Cheese, and guvcview.

    Read the article

  • What is the default file system of /var/run, /var/lock

    - by Casey
    Trying to figure out if my /var/run is using disk or not. See the command output: $ df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg0-root 40G 15G 26G 36% / none 3.9G 340K 3.9G 1% /dev none 3.9G 1.1M 3.9G 1% /dev/shm tmpfs 3.9G 600K 3.9G 1% /tmp none 3.9G 452K 3.9G 1% /var/run none 3.9G 0 3.9G 0% /var/lock none 3.9G 0 3.9G 0% /lib/init/rw /dev/md0 236M 59M 165M 27% /boot /dev/mapper/vg0-home 60G 58G 2.3G 97% /home

    Read the article

  • How to depict Import a file action in the Sequence diagram

    - by user970696
    Everyone says sequence diagrams are so easy but I just cannot figure this out. Basically user clicks on an 'Import from temp folder' button, the program opens a window with a list populated with filenames, user clicks on a filename, clicks on OK and the document is imported. I know the order of the actions but how to depict e.g. populating a list, or selecting an item from a list? So I assume the objects would be like: [USER] [ImportDialogWindow] [ListOfFiles:STRING] [?where to go with selected file]

    Read the article

  • How to compile deskew plugin for Gimp?

    - by mtone
    I'm interesting in using this Deskew plugin which appears somewhat old, with broken links in the gimp registry. https://github.com/prokoudine/gimp-deskew-plugin How do I go about installing it on Ubuntu 64-bit 12.10 running Gimp 2.8? I can't figure what I have to "configure" or "make" to compile the plugin. I understand the end result should be placed Noob-level: I know how to get around in a terminal, but that's about it. Thanks!

    Read the article

  • Customer won't decide, how to deal?

    - by Crazy Eddie
    I write software that involves the use of measured quantities, many input by the user, most displayed, that are fed into calculation models to simulate various physical thing-a-majigs. We have created a data type that allows us to associate a numeric value with a unit, we call these "quantities" (big duh). Quantities and units are unique to dimension. You can't attach kilogram to a length for example. Math on quantities does automatic unit conversion to SI and the type is dimension safe (you can't assign a weight to a pressure for example). Custom UI components have been developed that display the value and its unit and/or allow the user to edit them. Dimensionless quantities, having no units, are a single, custom case implemented within the system. There's a set of related quantities such that our target audience apparently uses them interchangeably. The quantities are used in special units that embed the conversion factors for the related quantity dimensions...in other words, when using these units converting from one to another simply involves multiplying the value by 1 to the dimensional difference. However, conversion to/from the calculation system (SI) still involves these factors. One of these related quantities is a dimensionless one that represents a ratio. I simply can't get the "customer" to recognize the necessity of distinguishing these values and their use. They've picked one and want to use it everywhere, customizing the way we deal with it in special places. In this case they've picked one of the dimensions that has a unit...BUT, they don't want there to be a unit (GRR!!!). This of course is causing us to implement these special overrides for our UI elements and such. That of course is often times forgotten and worse...after a couple months everyone forgets why it was necessary and why we're using this dimensional value, calling it the wrong thing, and disabling the unit. I could just ignore the "customer" and implement the type as the dimensionless quantity, which makes most sense. However, that leaves the team responsible for figuring it out when they've given us a formula using one of the other quantities. We have to not only figure out that it's happening, we have to decide what to do. This isn't a trivial deal. The other option is just to say to hell with it, do it the customer's way, and let it waste continued time and effort because it's just downright confusing as hell. However, I can't count the amount of times someone has said, "Why is this being done this way, it makes no sense at all," and the team goes off the deep end trying to figure it out. What would you do? Currently I'm still attempting to convince them that even if they use terms interchangeably, we at the least can't do that within the product discussion. Don't have high hopes though.

    Read the article

  • OK, How Does SEO Work?

    SEO, which is short for Search Engine Optimisation, works by making your site "friendlier" for search engines such as Google to list in their index. No-one knows for sure just how many pages Google has indexed. It gave up posting that figure some time ago as it's irrelevant to the average internet surfer - we only want relevant results when we're searching and don't really care about the literally millions of pages that were discarded on the way.

    Read the article

  • Translating Your Customizations

    - by Richard Bingham
    This blog post explains the basics of translating the customizations you can make to Fusion Applications products, with the inclusion of information for both composer-based customizations and the generic design-time customizations done via JDeveloper. Introduction Like most Oracle Applications, Fusion Applications installs on-premise with a US-English base language that is, in Release 7, supported by the option to add up to a total of 22 additional language packs (In Oracle Cloud production environments languages are pre-installed already). As such many organizations offer their users the option of working with their local language, and logically that should also apply for any customizations as well. Composer-based UI Customizations Customizations made in Page Composer take into consideration the session LOCALE, as set in the user preferences screen, during all customization work, and stores the customization in the MDS repository accordingly. As such the actual new or changed values used will only apply for the same language under which the customization was made, and text for any other languages requires a separate upload. See the Resource Bundles section below, which incidentally also applies to custom UI changes done in JDeveloper. You may have noticed this when you select the “Select Text Resource” menu option when editing the text on a page. Using this ensures that the resource bundles are used, whereas if you define a static value in Expression Builder it will never be available for translation. Notice in the screenshot below the “What’s New” custom value I have already defined using the ‘Select Text Resource’ feature is internally using the adfBundle groovy function to pull the custom value for my key (RT_S_1) from the ComposerOverrideBundle. Figure 1 – Page Composer showing the override bundle being used. Business Objects Customizing the Business Objects available in the Applications Composer tool for the CRM products, such as adding additional fields, also operates using the session language. Translating these additional values for these fields into other installed languages requires loading additional resource bundles, again as described below. Reports and Analytics Most customizations to Reports and BI Analytics are just essentially reorganizations and visualizations of existing number and text data from the system, and as such will use the appropriate values based on the users session language. Where a translated value or string exists for that session language, it will be used without the need for additional work. Extending through the addition of brand new reports and analytics requires another method of loading the translated strings, as part of what is known as ‘Localizing’ the BI Catalog and Metadata. This time it is via an export/import of XML data through the BI Administrators console, and is described in the OBIEE Admin Guide. Fusion Applications reports based on BI Publisher are already defined in template-per-locale, and in addition provide an extra process for getting the data for translation and reloading. This again uses the standard resource bundle format. Loading a custom report is illustrated in this video from our YouTube channel which shows the screen for both setting the template local and running an export for translation. Fusion Applications Menus Whilst the seeded Navigator and Global Menu values are fully translated when the additional language is installed, if they are customized then the change or new menu item will apply universally, not currently per language. This is set to change in a future release with the new UI Text Editor feature described below. More on Resource Bundles As mentioned above, to provide translations for most of your customizations you need to add values to a resource bundle. This is an industry open standard (OASIS) format XML file with the extension .xliff, and store translated values for the strings used by ADF at run-time. The general process is that these values are exported from the MDS repository, manually edited, and then imported back in again.This needs to be done by an administrator, via either WLST commands or through Enterprise Manager as per the screenshot below. This is detailed out in the Fusion Applications Extensibility Guide. For SaaS environments the Cloud Operations team can assist. Figure 2 – Enterprise Manager’s MDS export used getting resource bundles for manual translation and re-imported on the same screen. All customized strings are stored in an override bundle (xliff file) for each locale, suffixed with the language initials, with English ones being saved to the default. As such each language bundle can be easily identified and updated. Similarly if you used JDeveloper to create your own applications as extensions to Fusion Applications you would use the native support for resource bundles, and add them into the faces-config.xml file for inclusion in your application. An example is this ADF customization video from our YouTube channel. JDeveloper also supports automatic synchronization between your underlying resource bundles and any translatable strings you add – very handy. For more information see chapters on “Using Automatic Resource Bundle Integration in JDeveloper” and “Manually Defining Resource Bundles and Locales” in the Oracle Fusion Middleware Web User Interface Developer’s Guide for Oracle Application Development Framework. FND Messages and Look-ups FND Messages, as defined here, are not used for UI labels (they are known as ‘strings’), but are the responses back to users as a result of an action, such as from a page submit. Each ‘message’ is defined and stored in the related database table (FND_MESSAGES_B), with another (FND_MESSAGES_TL) holding any language-specific values. These come seeded with the additional language installs, however if you customize the messages via the “Manage Messages” task in Functional Setup Manager, or add new ones, then currently (in Release 7) you’ll need to repeat it for each language. Figure 3 – An FND Message defined in an English user session. Similarly Look-ups are stored in a translation table (FND_LOOKUP_VALUES_TL) where appropriate, and can be customized by setting the users session language and making the change  in the Setup and Maintenance task entitled “Manage [Standard|Common] Look-ups”. Online Help Yes, in fact all the seeded help is applied as part of each language pack install as part of the post-install provisioning process. If you are editing or adding custom online help then the Create Help screen provides a drop-down of which language your help customization will apply to. This is shown in the video below from our YouTube channel, and obviously you’ll need to it for each language in use. What is Coming for Translations? Currently planned for Release 8 is something called the User Interface (UI) Text Editor. This tool will allow the editing of all the text shown on the pages and forms of Fusion Application. This will provide a search based on a particular term or word, say “Worker”, and will allow it to be adjusted, say to “Employee”, which then updates all the Resource Bundles that contain it. In the case of multi-language environments, it will use the users session language (locale) to know which Resource Bundles to apply the change to. This capability will also support customization sandboxes, to help ensure changes can be tested and approved.  It is also interesting to note that the design currently allows any page-specific customizations done using Page Composer or Application Composer to over-write the global changes done via the UI Text Editor, allowing for special context-sensitive values to still be used. Further Reading and Resources The following short list provides the mains resources for digging into more detail on translation support for both Composer and JDeveloper customization projects. There is a dedicated chapter entitled “Translating Custom Text” in the Fusion Applications Extensibility Guide. This has good examples and steps for many tasks, especially administering resource bundles. Using localization formatting (numbers, dates etc) for design-time changes is well documented in the Fusion Applications Developer Guide. For more guidelines on general design-time globalization, see either the ‘Internationalizing and Localizing Pages’ chapter in the Oracle Fusion Middleware Web User Interface Developer’s Guide for Oracle Application Development Framework (Oracle Fusion Applications Edition) or the general Oracle Database Globalization Support Guide. The Oracle Architecture ‘A-Team’ provided a recent post on customizing the user session timeout popup, using design-time changes to resource bundles. It has detailed step-by-step examples which can be a useful illustration.

    Read the article

  • We've completed the first iteration

    - by CliveT
    There are a lot of features in C# that are implemented by the compiler and not by the underlying platform. One such feature is a lambda expression. Since local variables cannot be accessed once the current method activation finishes, the compiler has to go out of its way to generate a new class which acts as a home for any variable whose lifetime needs to be extended past the activation of the procedure. Take the following example:     Random generator = new Random();     Func func = () = generator.Next(10); In this case, the compiler generates a new class called c_DisplayClass1 which is marked with the CompilerGenerated attribute. [CompilerGenerated] private sealed class c__DisplayClass1 {     // Fields     public Random generator;     // Methods     public int b__0()     {         return this.generator.Next(10);     } } Two quick comments on this: (i)    A display was the means that compilers for languages like Algol recorded the various lexical contours of the nested procedure activations on the stack. I imagine that this is what has led to the name. (ii)    It is a shame that the same attribute is used to mark all compiler generated classes as it makes it hard to figure out what they are being used for. Indeed, you could imagine optimisations that the runtime could perform if it knew that classes corresponded to certain high level concepts. We can see that the local variable generator has been turned into a field in the class, and the body of the lambda expression has been turned into a method of the new class. The code that builds the Func object simply constructs an instance of this class and initialises the fields to their initial values.     c__DisplayClass1 class2 = new c__DisplayClass1();     class2.generator = new Random();     Func func = new Func(class2.b__0); Reflector already contains code to spot this pattern of code and reproduce the form containing the lambda expression, so this is example is correctly decompiled. The use of compiler generated code is even more spectacular in the case of iterators. C# introduced the idea of a method that could automatically store its state between calls, so that it can pick up where it left off. The code can express the logical flow with yield return and yield break denoting places where the method should return a particular value and be prepared to resume.         {             yield return 1;             yield return 2;             yield return 3;         } Of course, there was already a .NET pattern for expressing the idea of returning a sequence of values with the computation proceeding lazily (in the sense that the work for the next value is executed on demand). This is expressed by the IEnumerable interface with its Current property for fetching the current value and the MoveNext method for forcing the computation of the next value. The sequence is terminated when this method returns false. The C# compiler links these two ideas together so that an IEnumerator returning method using the yield keyword causes the compiler to produce the implementation of an Iterator. Take the following piece of code.         IEnumerable GetItems()         {             yield return 1;             yield return 2;             yield return 3;         } The compiler implements this by defining a new class that implements a state machine. This has an integer state that records which yield point we should go to if we are resumed. It also has a field that records the Current value of the enumerator and a field for recording the thread. This latter value is used for optimising the creation of iterator instances. [CompilerGenerated] private sealed class d__0 : IEnumerable, IEnumerable, IEnumerator, IEnumerator, IDisposable {     // Fields     private int 1__state;     private int 2__current;     public Program 4__this;     private int l__initialThreadId; The body gets converted into the code to construct and initialize this new class. private IEnumerable GetItems() {     d__0 d__ = new d__0(-2);     d__.4__this = this;     return d__; } When the class is constructed we set the state, which was passed through as -2 and the current thread. public d__0(int 1__state) {     this.1__state = 1__state;     this.l__initialThreadId = Thread.CurrentThread.ManagedThreadId; } The state needs to be set to 0 to represent a valid enumerator and this is done in the GetEnumerator method which optimises for the usual case where the returned enumerator is only used once. IEnumerator IEnumerable.GetEnumerator() {     if ((Thread.CurrentThread.ManagedThreadId == this.l__initialThreadId)               && (this.1__state == -2))     {         this.1__state = 0;         return this;     } The state machine itself is implemented inside the MoveNext method. private bool MoveNext() {     switch (this.1__state)     {         case 0:             this.1__state = -1;             this.2__current = 1;             this.1__state = 1;             return true;         case 1:             this.1__state = -1;             this.2__current = 2;             this.1__state = 2;             return true;         case 2:             this.1__state = -1;             this.2__current = 3;             this.1__state = 3;             return true;         case 3:             this.1__state = -1;             break;     }     return false; } At each stage, the current value of the state is used to determine how far we got, and then we generate the next value which we return after recording the next state. Finally we return false from the MoveNext to signify the end of the sequence. Of course, that example was really simple. The original method body didn't have any local variables. Any local variables need to live between the calls to MoveNext and so they need to be transformed into fields in much the same way that we did in the case of the lambda expression. More complicated MoveNext methods are required to deal with resources that need to be disposed when the iterator finishes, and sometimes the compiler uses a temporary variable to hold the return value. Why all of this explanation? We've implemented the de-compilation of iterators in the current EAP version of Reflector (7). This contrasts with previous version where all you could do was look at the MoveNext method and try to figure out the control flow. There's a fair amount of things we have to do. We have to spot the use of a CompilerGenerated class which implements the Enumerator pattern. We need to go to the class and figure out the fields corresponding to the local variables. We then need to go to the MoveNext method and try to break it into the various possible states and spot the state transitions. We can then take these pieces and put them back together into an object model that uses yield return to show the transition points. After that Reflector can carry on optimising using its usual optimisations. The pattern matching is currently a little too sensitive to changes in the code generation, and we only do a limited analysis of the MoveNext method to determine use of the compiler generated fields. In some ways, it is a pity that iterators are compiled away and there is no metadata that reflects the original intent. Without it, we are always going to dependent on our knowledge of the compiler's implementation. For example, we have noticed that the Async CTP changes the way that iterators are code generated, so we'll have to do some more work to support that. However, with that warning in place, we seem to do a reasonable job of decompiling the iterators that are built into the framework. Hopefully, the EAP will give us a chance to find examples where we don't spot the pattern correctly or regenerate the wrong code, and we can improve things. Please give it a go, and report any problems.

    Read the article

< Previous Page | 29 30 31 32 33 34 35 36 37 38 39 40  | Next Page >