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  • Fade between looped background images using jQuery

    - by da5id
    I'm trying to get the background image of a legacy div (by which I mean it already has a background image, which I cannot control & thus have to initially over-write) to smoothly fade between new images indefinitely. Here's what I have so far: var images = [ "/images/home/19041085158.jpg", "/images/home/19041085513.jpg", "/images/home/19041085612.jpg" ]; var counter = 0; setInterval(function() { $(".home_banner").css('backgroundImage', 'url("'+images[counter]+'")'); counter++; if (counter == images.length) { counter = 0; } }, 2000); Trouble is, it's not smooth (I'm aiming for something like the innerfade plugin). EDIT: question originally said "and it's not indefinite (it only runs once through the array).", but Mario corrected my stupid naming error. EDIT2: I'm now using Reigel's answer (see below), which works perfectly, but I still can't find any way to fade between the images smoothly. All help greatfully appreciated :)

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  • how create a sql database fom a stongly typed dataset

    - by Keith Vinson
    I'm looking for an easy way to transfer a database schema I have developed inside visual studio as a strongly typed dataset (xsd file) into a corresponding sql server database. Silly me I assumed the process would be forthright, but I can't find out how to do it. I assume I could duplicate the tables column by column, but that seems so error prone. Does anyone know of a way to perform the schema transfer like this? Maybe a tool to translate the xsd file into a corresponding sql server ddl file? Final thought once I have the schema transferred moving data around between the two data stores will be straight forward, its just getting the schemas synced that has me stumped... Thanks, Keith

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  • Webview can't type in, is that because of missing setting?

    - by Pentium10
    I have an Android application that connects to Facebook to request authorization of an Application. I use the following setting in the WebView, but once the view is loaded, I can't type in login details. What I am missing? WebView webview; webview = (WebView) findViewById(R.id.facebookview); webview.getSettings().setJavaScriptEnabled(true); webview.setWebViewClient(new FacebookWebViewClient()); webview .loadUrl("http://www.connect.facebook.com/login.php?return_session=1&nochrome=1&fbconnect=1&extern=2&connect_display=popup&api_key=" + FConnect.API_KEY + "&v=1.0&next=" + FConnect.SUCCESS_URL + "%3Ffb_login%26fname%3D_opener&cancel_url=" + FConnect.CANCEL_URL + "%23fname%3D_opener%26%257B%2522t%2522%253A3%252C%2522h%2522%253A%2522fbCancelLogin%2522%252C%2522sid%2522%253A%25220.741%2522%257D&channel_url=" + FConnect.XD_RECEIVER);

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  • ActiveRecord Save Dependent Model

    - by Dmitriy Likhten
    I am trying to save a model with it's dependency models being saved. Model1 has_many :model2, :autosave => true Model2 belongs_to :model1 has_many :model3, :autosave => true Model3 belongs_to :model2 I want to save Model1, and have Model2 and 3 save as well. I tried this without and with the autosave feature. What winds up happening is Model1 is saved, Model2 is saved, Model3 is untouched. Is there a way to tell ActiveRecord that for this save I want to save the model and all child models all at once? As a side note, all 3 are just created and are not in the database. I cannot do .create on the models because I cannot save them until all validation passes and all business logic succeeds (has to be a transaction).

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  • High Throughput and Windows Workflow Foundation

    - by SometimesUseful
    Can WWF handle high throughput scenarios where several dozen records are 'actively' being processed in parallel at any one time? We want to build a workflow process which handles a few thousand records per hour. Each record takes up to a minute to process, because it makes external web service calls. We are testing Windows Workflow Foundation to do this. But our demo programs show processing of each record appear to be running in sequence not in parallel, when we use parallel activities to process several records at once within one workflow instance. Should we use multiple workflow instances or parallel activities? Are there any known patterns for high performance WWF processing?

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  • Android Image Problem and threshold

    - by Danny_E
    Hey Guys, Long time reader never posted until now. Im having some trouble with Android, im implementing a library called JJIL its an open source imaging library. My problem is this i need to run some analysis on an image and to do so i need to have it in jjil.core.image format and once those processes are complete i need to convert the changed image from jjil.core.image to java.awt.image. I cant seem to find a method of doing this does anyone have any ideas or have any experience with this? I would be grateful of any help. Danny

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  • Problems compiling an external library on linux...

    - by Kris
    So I am trying to compile the libssh2 library on linux, but when I try to compile the example it comes up with a lot of errors, and even though I include the headerfile it asks for, it still asks for it. Here are the error messages and the resulting messages: ~/ gcc -include /home/Roosevelt/libssh2-1.2.5/src/libssh2_config.h -o lolbaise /home/Roosevelt/libssh2-1.2.5/example/scp.c /home/Roosevelt/libssh2-1.2.5/example/scp.c:7:28: error: libssh2_config.h: No such file or directory /home/Roosevelt/libssh2-1.2.5/example/scp.c: In function 'main': /home/Roosevelt/libssh2-1.2.5/example/scp.c:39: error: storage size of 'sin' isn't known /home/Roosevelt/libssh2-1.2.5/example/scp.c:81: error: 'AF_INET' undeclared (first use in this function) /home/Roosevelt/libssh2-1.2.5/example/scp.c:81: error: (Each undeclared identifier is reported only once /home/Roosevelt/libssh2-1.2.5/example/scp.c:81: error: for each function it appears in.) /home/Roosevelt/libssh2-1.2.5/example/scp.c:81: error: 'SOCK_STREAM' undeclared (first use in this function) /home/Roosevelt/libssh2-1.2.5/example/scp.c:87: error: invalid application of 'sizeof' to incomplete type 'struct sockaddr_in'

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  • Convert wife/husband/partner to a programmer.

    - by Stefan
    originally posted by Stefan: How many of you have had the thought of educate your partner and invite him/her to the beautiful world of programming? I once started to give my wife lessons twice a week, It was a competition between me and another programmer, we thought it would be nice to have our wives understand why we work as programmers and also have it as a hobby sitting all night long. Maybe we could get our wives to feel the power too? After a couple of months my wife didn't like the idea any more, it was too hard to understand she thought, same for my friends wife. So now we are thinking of some project that would be too fun for our wives to turn down just to get the spirit up again. It would be nice to hand over a project to my wife, "Can you debug this for me, please? There are some strange error on module xxx." :) Maybe I'm crazy, what do you think?

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  • Alternative way of developing for ASP.NET to WebForms - Any problems with this?

    - by John
    So I have been developing in ASP.NET WebForms for some time now but often get annoyed with all the overhead (like ViewState and all the JavaScript it generates), and the way WebForms takes over a lot of the HTML generation. Sometimes I just want full control over the markup and produce efficient HTML of my own so I have been experimenting with what I like to call HtmlForms. Essentially this is using ASP.NET WebForms but without the form runat="server" tag. Without this tag, ASP.NET does not seem to add anything to the page at all. From some basic tests it seems that it runs well and you still have the ability to use code-behind pages, and many ASP.NET controls such as repeaters. Of course without the form runat="server" many controls won't work. A post at Enterprise Software Development lists the controls that do require the tag. From that list you will see that all of the form elements like TextBoxes, DropDownLists, RadioButtons, etc cannot be used. Instead you use normal HTML form controls. But how do you access these HTML controls from the code behind? Retrieving values on post back is easy, you just use Request.QueryString or Request.Form. But passing data to the control could be a little messy. Do you use a ASP.NET Literal control in the value field or do you use <%= value % in the markup page? I found it best to add runat="server" to my HTML controls and then you can access the control in your code-behind like this: ((HtmlInputText)txtName).Value = "blah"; Here's a example that shows what you can do with a textbox and drop down list: Default.aspx <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="NoForm.Default" %> <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="NoForm.Default" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> </head> <body> <form action="" method="post"> <label for="txtName">Name:</label> <input id="txtName" name="txtName" runat="server" /><br /> <label for="ddlState">State:</label> <select id="ddlState" name="ddlState" runat="server"> <option value=""></option> </select><br /> <input type="submit" value="Submit" /> </form> </body> </html> Default.aspx.cs using System; using System.Web.UI.HtmlControls; using System.Web.UI.WebControls; namespace NoForm { public partial class Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { //Default values string name = string.Empty; string state = string.Empty; if (Request.RequestType == "POST") { //If form submitted (post back) name = Request.Form["txtName"]; state = Request.Form["ddlState"]; //Server side form validation would go here //and actions to process form and redirect } ((HtmlInputText)txtName).Value = name; ((HtmlSelect)ddlState).Items.Add(new ListItem("ACT")); ((HtmlSelect)ddlState).Items.Add(new ListItem("NSW")); ((HtmlSelect)ddlState).Items.Add(new ListItem("NT")); ((HtmlSelect)ddlState).Items.Add(new ListItem("QLD")); ((HtmlSelect)ddlState).Items.Add(new ListItem("SA")); ((HtmlSelect)ddlState).Items.Add(new ListItem("TAS")); ((HtmlSelect)ddlState).Items.Add(new ListItem("VIC")); ((HtmlSelect)ddlState).Items.Add(new ListItem("WA")); if (((HtmlSelect)ddlState).Items.FindByValue(state) != null) ((HtmlSelect)ddlState).Value = state; } } } As you can see, you have similar functionality to ASP.NET server controls but more control over the final markup, and less overhead like ViewState and all the JavaScript ASP.NET adds. Interestingly you can also use HttpPostedFile to handle file uploads using your own input type="file" control (and necessary form enctype="multipart/form-data"). So my question is can you see any problems with this method, and any thoughts on it's usefulness? I have further details and tests on my blog.

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  • UITableView Cell IndexPath

    - by Reonarudo
    Hello, Can anyone tell me how can I get a cell IndexPath? I was saving the IndexPath in the tableView: cellForRowAtIndexPath: method but this only loads when the cell is viewed and I need to know its index path on the viewDidLoad method. this resulted in a null value because as I said it only loads its value after the cell was viewed once. Thank you. EDIT The intention is being able to jump to a specific cell that has its specific number but its not linear with the sections and rows count.

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  • How can I build a Truth Table Generator?

    - by KingNestor
    I'm looking to write a Truth Table Generator as a personal project. There are several web-based online ones here and here. (Example screenshot of an existing Truth Table Generator) I have the following questions: How should I go about parsing expressions like: ((P = Q) & (Q = R)) = (P = R) Should I use a parser generator like ANTLr or YACC, or use straight regular expressions? Once I have the expression parsed, how should I go about generating the truth table? Each section of the expression needs to be divided up into its smallest components and re-built from the left side of the table to the right. How would I evaluate something like that? Can anyone provide me with tips concerning the parsing of these arbitrary expressions and eventually evaluating the parsed expression?

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  • Lamp with mod_fastcgi

    - by Jonathan
    Hi! I am building a cgi application, and now I would like it to be like an application that stands and parses each connection, with this, I can have all session variables saved in memory instead of saving them to file(or anyother place) and loading them again on a new connection I am using lamp within a linux vmware but I can't seem to find how to install the module for it to work and what to change in the httpd.conf. I tried to compile the module, but I couldn't because my apache isn't a regular instalation, its a lamp already built one, and it seems that the mod needs the apache directory to be compiled. I saw some coding examples out there, so I guess is not that hard once its runing ok with Apache Can you help me with this please? Thanks, Joe

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  • Seeking through a streamed MP3 file with HTML5 <audio> tag

    - by Kyle Slattery
    Hopefully someone can help me out with this. I'm playing around with a node.js server that streams audio to a client, and I want to create an HTML5 player. Right now, I'm streaming the code from node using chunked encoding, and if you go directly to the URL, it works great. What I'd like to do is embed this using the HTML5 <audio> tag, like so: <audio src="http://server/stream?file=123"> where /stream is the endpoint for the node server to stream the MP3. The HTML5 player loads fine in Safari and Chrome, but it doesn't allow me to seek, and Safari even says it's a "Live Broadcast". In the headers of /stream, I include the file size and file type, and the response gets ended properly. Any thoughts on how I could get around this? I certainly could just send the whole file at once, but then the player would wait until the whole thing is downloaded--I'd rather stream it.

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  • Nhibernate setting query time out period for commands and pessimistic locking

    - by Nagesh
    I wish to specify a specific command timeout (or LOCK_TIMEOUT) for an SQL and once this time out is reached an exception (or alert) has to be raised in nHibernate. The following is an example pseudo-code what I have written: using (var session = sessionFactory.OpenSession()) { using (var sqlTrans = session.BeginTransaction()) { ICriteria criteria = session.CreateCriteria(typeof(Foo)); criteria.SetTimeout(5); //Here is the specified command timout, eg: property SqlCommand.CommandTimeout Foo fooObject = session.Load<Foo>(primaryKeyIntegerValue, LockMode.Force); session.SaveOrUpdate(fooObject); sqlTrans.Commit(); } } In SQL server we used to achieve this using the following SQL: BEGIN TRAN SET LOCK_TIMEOUT 500 SELECT * FROM Foo WITH (UPDLOCK, ROWLOCK) WHERE PrimaryKeyID = 1000001 If PrimaryKeyID row would have locked in other transaction the following error message is being shown by SQL Server: Msg 1222, Level 16, State 51, Line 3 Lock request time out period exceeded Similarly I wish to show a lock time out or command time out information using nHibernate. Please help me to achieve this. Thanks in advance for your help.

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  • #OOW 2012 @PARIS...talking Oracle and Clouds, and Optimized Datacenter

    - by Eric Bezille
    For those of you who want to get most out of Oracle technologies to evolve your IT to the Next Wave, I encourage you to register to the up coming Oracle Optimized Datacenter event that will take place in Paris on November 28th. You will get the opportunity to exchange with Oracle experts and customers having successfully evolve their IT by leveraging Oracle technologies. You will also get the latest news on some of the Oracle systems announcements made during OOW 2012. During this event we will make an update about Oracle and Clouds, from private to public and hybrid models. So in preparing this session, I thought it was a good start to make a status of Cloud Computing in France, and CIO requirements in particular. Starting in 2009 with the first Cloud Camp in Paris, the market has evolved, but the basics are still the same : think hybrid. From Traditional IT to Clouds One size doesn't fit all, and for big companies having already an IT in place, there will be parts eligible to external (public) cloud, and parts that would be required to stay inside the firewalls, so ability to integrate both side is key.  None the less, one of the major impact of Cloud Computing trend on IT, reported by Forrester, is the pressure it makes on CIO to evolve towards the same model that end-users are now used to in their day to day life, where self-service and flexibility are paramount. This is what is driving IT to transform itself toward "a Global Service Provider", or for some as "IT "is" the Business" (see : Gartner Identifies Four Futures for IT and CIO), and for both models toward a Private Cloud Service Provider. In this journey, there is still a big difference between most of existing external Cloud and a firm IT : the number of applications that a CIO has to manage. Most cloud providers today are overly specialized, but at the end of the day, there are really few business processes that rely on only one application. So CIOs has to combine everything together external and internal. And for the internal parts that they will have to make them evolve to a Private Cloud, the scope can be very large. This will often require CIOs to evolve from their traditional approach to more disruptive ones, the time has come to introduce new standards and processes, if they want to succeed. So let's have a look at the different Cloud models, what type of users they are addressing, what value they bring and most importantly what needs to be done by the  Cloud Provider, and what is left over to the user. IaaS, PaaS, SaaS : what's provided and what needs to be done First of all the Cloud Provider will have to provide all the infrastructure needed to deliver the service. And the more value IT will want to provide, the more IT will have to deliver and integrate : from disks to applications. As we can see in the above picture, providing pure IaaS, left a lot to cover for the end-user, that’s why the end-user targeted by this Cloud Service is IT people. If you want to bring more value to developers, you need to provide to them a development platform ready to use, which is what PaaS is standing for, by providing not only the processors power, storage and OS, but also the Database and Middleware platform. SaaS being the last mile of the Cloud, providing an application ready to use by business users, the remaining part for the end-users being configuring and specifying the application for their specific usage. In addition to that, there are common challenges encompassing all type of Cloud Services : Security : covering all aspect, not only of users management but also data flows and data privacy Charge back : measuring what is used and by whom Application management : providing capabilities not only to deploy, but also to upgrade, from OS for IaaS, Database, and Middleware for PaaS, to a full Business Application for SaaS. Scalability : ability to evolve ALL the components of the Cloud Provider stack as needed Availability : ability to cover “always on” requirements Efficiency : providing a infrastructure that leverage shared resources in an efficient way and still comply to SLA (performances, availability, scalability, and ability to evolve) Automation : providing the orchestration of ALL the components in all service life-cycle (deployment, growth & shrink (elasticity), upgrades,...) Management : providing monitoring, configuring and self-service up to the end-users Oracle Strategy and Clouds For CIOs to succeed in their Private Cloud implementation, means that they encompass all those aspects for each component life-cycle that they selected to build their Cloud. That’s where a multi-vendors layered approach comes short in terms of efficiency. That’s the reason why Oracle focus on taking care of all those aspects directly at Engineering level, to truly provide efficient Cloud Services solutions for IaaS, PaaS and SaaS. We are going as far as embedding software functions in hardware (storage, processor level,...) to ensure the best SLA with the highest efficiency. The beauty of it, as we rely on standards, is that the Oracle components that you are running today in-house, are exactly the same that we are using to build Clouds, bringing you flexibility, reversibility and fast path to adoption. With Oracle Engineered Systems (Exadata, Exalogic & SPARC SuperCluster, more specifically, when talking about Cloud), we are delivering all those components hardware and software already engineered together at Oracle factory, with a single pane of glace for the management of ALL the components through Oracle Enterprise Manager, and with high-availability, scalability and ability to evolve by design. To give you a feeling of what does that bring in terms just of implementation project timeline, for example with Oracle SPARC SuperCluster, we have a consistent track of record to have the system plug into existing Datacenter and ready in a week. This includes Oracle Database, OS, virtualization, Database Storage (Exadata Storage Cells in this case), Application Storage, and all network configuration. This strategy enable CIOs to very quickly build Cloud Services, taking out not only the complexity of integrating everything together but also taking out the automation and evolution complexity and cost. I invite you to discuss all those aspect in regards of your particular context face2face on November 28th.

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  • Delete temp file during finally vs delete output file during catch

    - by Russell
    This is in Java 6. I've seen more than once that people create temp files, do something, then rename it to the output file. Everything is wrapped in a try-finally block, where the temp file is deleted in finally in case something goes wrong in between. try { //do something with tempFile //do something with tempFile //do something with tempFile tempFile.renameTo(outputFile); } finally { if (tempFile.exists()) tempFile.delete() } I was wondering what are the benefits of doing that instead of doing something to the output file directly and delete it in case of exceptions. try { //do something with outputFile //do something with outputFile //do something with outputFile } catch (Exception e) { if (outputFile.exists()) outputFile.delete(); } My guess is that deleting temp files in finally benefits me when the try block can throw many kinds of exceptions. Is my guess right? What else?

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  • jquery - loose click() event after ajax call ???

    - by niczoom
    At the following webpage liamharding.com/pgi.php I have an option panel on the left side of the page which opens and close's upon clicking the panels 'arrow', this works fine until you select a market (for testing use one of the 'Random Walk' markets and click 'Show/Refesh Graphs'), this then makes an ajax call using get_graph(forexName, myCount, divIsNew) function. Once this call is completed a graph(s) is displayed and then my options panels click() event does not work? The ajax call returns the data in a variable ajax_data, the problem happens when I perform the following code var jq_ajax_data = $("<div/>").html(ajax_data); . I need to wrap it in a so I can extract data from it using jQuery. If this line of code is commented out the click() event works fine ?? Hope somebody can help, I have spent a lot of time but cant find what the problem is.

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  • BackgroundWorker and WebBrowser Control

    - by James Jeffery
    Is it possible/recommended to use background worker threads with the web browser control? I am creating a bot that searches google for keywords, then checks for sites in the first 10 pages to see if a site is ranked. The user can provide a maximum of 20 sites to check, and can use proxies. So ideally I'd like to have 5 threads working at once. Is it possible? I might have heard somewhere that there are problems with WebBrowser control and threads.

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  • Using unicodedata.normalize in Python 2.7

    - by dpitch40
    Once again, I am very confused with a unicode question. I can't figure out how to successfully use unicodedata.normalize to convert non-ASCII characters as expected. For instance, I want to convert the string u"Cœur" To u"Coeur" I am pretty sure that unicodedata.normalize is the way to do this, but I can't get it to work. It just leaves the string unchanged. >>> s = u"Cœur" >>> unicodedata.normalize('NFKD', s) == s True What am I doing wrong?

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  • Java Mail timeout & connectiontimeout handling

    - by Gnanam
    Hi, I'm using JavaMail to send email requests to an SMTP server. I would like to set both "mail.smtp.connectiontimeout" and "mail.smtp.timeout" properties within my code. Programmatically, I want to catch both when timeout and/or connectiontimeout operations are reached in Java and handle things accordingly. Handling in the sense, I need to retry the same email once again the next time. How do I handle this in Java/JavaMail? Is it possible to catch & handle this timeout operations?

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  • Java mobile: Android or Blackberry?

    - by jpartogi
    Hi all, Most of the questions on SO has been too generic, comparing iPhone, Android and Blackberry all at once. I want to ask your experience between developing on Android and Blackberry. From your experience as Java programmer: Which platform do you enjoy developing on the most? Which API do you find is well written and fun to code? Which development platform that is fun to work with? Which platform do you find most stable and less issues with? Android or Blackberry? Any other noteworthy checklists to share to Java programmers that want to choose whether to develop on Android or Blackberry? Thank you for sharing your experience with us here.

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  • Unable to call WMP's controls.play() function in VisualBasic

    - by A.J.
    I have the following code: http://pastebin.com/EgjbzqA2 which is basically just a stripped down version of http://www.dreamincode.net/forums/topic/57357-mymusic-player/. I want the program to play one file repeatedly, however, this function doesn't work for some reason. The program plays each file once and then stops. Private Sub Player3_PlayStateChange(ByVal NewState As Integer) Handles Player3.PlayStateChange Static Dim PlayAllowed As Boolean = True Select Case CType(NewState, WMPLib.WMPPlayState) Case WMPLib.WMPPlayState.wmppsReady If PlayAllowed Then Player3.controls.play() End If Case WMPLib.WMPPlayState.wmppsMediaEnded ' Start protection (without it next wouldn't play PlayAllowed = False ' Play track Player3.controls.play() ' End Protection PlayAllowed = True updatePlayer() End Select End Sub

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  • scheduled task or windows service

    - by czuroski
    Hello, I have to create an app that will read in some info from a db, process the data, write changes back to the db, and then send an email with these changes to some users or groups. I will be writing this in c#, and this process must be run once a week at a particular time. This will be running on a Windows 2008 Server. In the past, I would always go the route of creating a windows service with a timer and setting the time/day for it to be run in the app.config file so that it can be changed and only have to be restarted to catch the update. Recently, though, I have seen blog posts and such that recommend writing a console application and then using a scheduled task to execute it. I have read many posts talking to this very issue, but have not seen a definitive answer about which process is better. What do any of you think? Thanks for any thoughts.

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  • Visual Tree Enumeration

    - by codingbloke
    I feel compelled to post this blog because I find I’m repeatedly posting this same code in silverlight and windows-phone-7 answers in Stackoverflow. One common task that we feel we need to do is burrow into the visual tree in a Silverlight or Windows Phone 7 application (actually more recently I found myself doing this in WPF as well).  This allows access to details that aren’t exposed directly by some controls.  A good example of this sort of requirement is found in the “Restoring exact scroll position of a listbox in Windows Phone 7”  question on stackoverflow.  This required that the scroll position of the scroll viewer internal to a listbox be accessed. A caveat One caveat here is that we should seriously challenge the need for this burrowing since it may indicate that there is a design problem.  Burrowing into the visual tree or indeed burrowing out to containing ancestors could represent significant coupling between module boundaries and that generally isn’t a good idea. Why isn’t this idea just not cast aside as a no-no?  Well the whole concept of a “Templated Control”, which are in extensive use in these applications, opens the coupling between the content of the visual tree and the internal code of a control.   For example, I can completely change the appearance and positioning of elements that make up a ComboBox.  The ComboBox control relies on specific template parts having set names of a specified type being present in my template.  Rightly or wrongly this does kind of give license to writing code that has similar coupling. Hasn’t this been done already? Yes it has.  There are number of blogs already out there with similar solutions.  In fact if you are using Silverlight toolkit the VisualTreeExtensions class already provides this feature.  However I prefer my specific code because of the simplicity principle I hold to.  Only write the minimum code necessary to give all the features needed.  In this case I add just two extension methods Ancestors and Descendents, note I don’t bother with “Get” or “Visual” prefixes.  Also I haven’t added Parent or Children methods nor additional “AndSelf” methods because all but Children is achievable with the addition of some other Linq methods.  I decided to give Descendents an additional overload for depth hence a depth of 1 is equivalent to Children but this overload is a little more flexible than simply Children. So here is the code:- VisualTreeEnumeration public static class VisualTreeEnumeration {     public static IEnumerable<DependencyObject> Descendents(this DependencyObject root, int depth)     {         int count = VisualTreeHelper.GetChildrenCount(root);         for (int i = 0; i < count; i++)         {             var child = VisualTreeHelper.GetChild(root, i);             yield return child;             if (depth > 0)             {                 foreach (var descendent in Descendents(child, --depth))                     yield return descendent;             }         }     }     public static IEnumerable<DependencyObject> Descendents(this DependencyObject root)     {         return Descendents(root, Int32.MaxValue);     }     public static IEnumerable<DependencyObject> Ancestors(this DependencyObject root)     {         DependencyObject current = VisualTreeHelper.GetParent(root);         while (current != null)         {             yield return current;             current = VisualTreeHelper.GetParent(current);         }     } }   Usage examples The following are some examples of how to combine the above extension methods with Linq to generate the other axis scenarios that tree traversal code might require. Missing Axis Scenarios var parent = control.Ancestors().Take(1).FirstOrDefault(); var children = control.Descendents(1); var previousSiblings = control.Ancestors().Take(1)     .SelectMany(p => p.Descendents(1).TakeWhile(c => c != control)); var followingSiblings = control.Ancestors().Take(1)     .SelectMany(p => p.Descendents(1).SkipWhile(c => c != control).Skip(1)); var ancestorsAndSelf = Enumerable.Repeat((DependencyObject)control, 1)     .Concat(control.Ancestors()); var descendentsAndSelf = Enumerable.Repeat((DependencyObject)control, 1)     .Concat(control.Descendents()); You might ask why I don’t just include these in the VisualTreeEnumerator.  I don’t on the principle of only including code that is actually needed.  If you find that one or more of the above  is needed in your code then go ahead and create additional methods.  One of the downsides to Extension methods is that they can make finding the method you actually want in intellisense harder. Here are some real world usage scenarios for these methods:- Real World Scenarios //Gets the internal scrollviewer of a ListBox ScrollViewer sv = someListBox.Descendents().OfType<ScrollViewer>().FirstOrDefault(); // Get all text boxes in current UserControl:- var textBoxes = this.Descendents().OfType<TextBox>(); // All UIElement direct children of the layout root grid:- var topLevelElements = LayoutRoot.Descendents(0).OfType<UIElement>(); // Find the containing `ListBoxItem` for a UIElement:- var container = elem.Ancestors().OfType<ListBoxItem>().FirstOrDefault(); // Seek a button with the name "PinkElephants" even if outside of the current Namescope:- var pinkElephantsButton = this.Descendents()     .OfType<Button>()     .FirstOrDefault(b => b.Name == "PinkElephants"); //Clear all checkboxes with the name "Selector" in a Treeview foreach (CheckBox checkBox in elem.Descendents()     .OfType<CheckBox>().Where(c => c.Name == "Selector")) {     checkBox.IsChecked = false; }   The last couple of examples above demonstrate a common requirement of finding controls that have a specific name.  FindName will often not find these controls because they exist in a different namescope. Hope you find this useful, if not I’m just glad to be able to link to this blog in future stackoverflow answers.

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  • Clojure lots of threads

    - by Timothy Baldridge
    I just got done watching Rick Hickey's "Clojure Concurrency" talk, and I have a few questions about threads. Let's say I have a situation with lots of Agents, let's say 10,000 of them running one machine. I'd rather not have 10,000 CPU threads running at once, but I don't want threads to be blocked by the actions of other threads. In this example I won't really be waiting for replies, instead each Agent will be sending a message or two, and then waiting until it gets a message. How would I structure a program like this without getting 10k OS threads which would probably end up slowing the system down.

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