Search Results

Search found 3253 results on 131 pages for 'truth seeking fire walker'.

Page 123/131 | < Previous Page | 119 120 121 122 123 124 125 126 127 128 129 130  | Next Page >

  • Programmatically triggering events in Javascript for IE using jQuery

    - by Dan Herbert
    When an Event is triggered by a user in IE, it is set to the window.event object. The only way to see what triggered the event is by accessing the window.event object (as far as I know) This causes a problem in ASP.NET validators if an event is triggered programmatically, like when triggering an event through jQuery. In this case, the window.event object stores the last user-triggered event. When the onchange event is fired programmatically for a text box that has an ASP.NET validator attached to it, the validation breaks because it is looking at the element that fired last event, which is not the element the validator is for. Does anyone know a way around this? It seems like a problem that is solvable, but from looking online, most people just find ways to ignore the problem instead of solving it. To explain what I'm doing specifically: I'm using a jQuery time picker plugin on a text box that also has 2 ASP.NET validators associated with it. When the time is changed, I'm using an update panel to post back to the server to do some things dynamically, so I need the onchange event to fire in order to trigger the postback for that text box. The jQuery time picker operates by creating a hidden unordered list that is made visible when the text box is clicked. When one of the list items is clicked, the "change" event is fired programmatically for the text box through jQuery's change() method. Because the trigger for the event was a list item, IE sees the list item as the source of the event, not the text box, like it should. I'm not too concerned with this ASP.NET validator working as soon as the text box is changed, I just need the "change" event to be processed so my postback event is called for the text box. The problem is that the validator throws an exception in IE which stops any event from being triggered. Firefox (and I assume other browsers) don't have this issue. Only IE due to the different event model. Has anyone encountered this and seen how to fix it? I've found this problem reported several other places, but they offer no solutions: jQuery's forum, with the jQuery UI Datepicker and an ASP.NET Validator ASP.NET forums, bug with ValidatorOnChange() function

    Read the article

  • Force deletion of slot in boost::signals2

    - by villintehaspam
    Hi! I have found that boost::signals2 uses sort of a lazy deletion of connected slots, which makes it difficult to use connections as something that manages lifetimes of objects. I am looking for a way to force slots to be deleted directly when disconnected. Any ideas on how to work around the problem by designing my code differently are also appreciated! This is my scenario: I have a Command class responsible for doing something that takes time asynchronously, looking something like this (simplified): class ActualWorker { public: boost::signals2<void ()> OnWorkComplete; }; class Command : boost::enable_shared_from_this<Command> { public: ... void Execute() { m_WorkerConnection = m_MyWorker.OnWorkDone.connect(boost::bind(&Command::Handle_OnWorkComplete, shared_from_this()); // launch asynchronous work here and return } boost::signals2<void ()> OnComplete; private: void Handle_OnWorkComplete() { // get a shared_ptr to ourselves to make sure that we live through // this function but don't keep ourselves alive if an exception occurs. shared_ptr<Command> me = shared_from_this(); // Disconnect from the signal, ideally deleting the slot object m_WorkerConnection.disconnect(); OnComplete(); // the shared_ptr now goes out of scope, ideally deleting this } ActualWorker m_MyWorker; boost::signals2::connection m_WorkerConnection; }; The class is invoked about like this: ... boost::shared_ptr<Command> cmd(new Command); cmd->OnComplete.connect( foo ); cmd->Execute(); // now go do something else, forget all about the cmd variable etcetera. the Command class keeps itself alive by getting a shared_ptr to itself which is bound to the ActualWorker signal using boost::bind. When the worker completes, the handler in Command is invoked. Now, since I would like the Command object to be destroyed, I disconnect from the signal as can be seen in the code above. The problem is that the actual slot object is not deleted when disconnected, it is only marked as invalid and then deleted at a later time. This in turn appears to depend on the signal to fire again, which it doesn't do in my case, leading to the slot never expiring. The boost::bind object thus never goes out of scope, holding a shared_ptr to my object that will never get deleted. I can work around this by binding using the this pointer instead of a shared_ptr and then keeping my object alive using a member shared_ptr which I then release in the handler function, but it kind of makes the design feel a bit overcomplicated. Is there a way to force signals2 to delete the slot when disconnecting? Or is there something else I could do to simplify the design? Any comments are appreciated!

    Read the article

  • 'Timeout Expired' error against local SQL Express on only 2 LINQ Methods...

    - by Refracted Paladin
    I am going to sum up my problem first and then offer massive details and what I have already tried. Summary: I have an internal winform app that uses Linq 2 Sql to connect to a local SQL Express database. Each user has there own DB and the DB stay in sync through Merge Replication with a Central DB. All DB's are SQL 2005(sp2or3). We have been using this app for over 5 months now but recently our users are getting a Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. Detailed: The strange part is they get that in two differnt locations(2 differnt LINQ Methods) and only the first time they fire in a given time period(~5mins). One LINQ method is pulling all records that match a FK ID and then Manipulating them to form a Heirarchy View for a TreeView. The second is pulling all records that match a FK ID and dumping them into a DataGridView. The only things I can find in common with the 2 are that the first IS an IEnumerable and the second converts itself from IQueryable - IEnumerable - DataTable... I looked at the query's in Profiler and they 'seemed' normal. They are not very complicated querys. They are only pulling back 10 - 90 records, from one table. Any thoughts, suggestions, hints whatever would be greatly appreciated. I am at my wit's end on this.... public IList<CaseNoteTreeItem> GetTreeViewDataAsList(int personID) { var myContext = MatrixDataContext.Create(); var caseNotesTree = from cn in myContext.tblCaseNotes where cn.PersonID == personID orderby cn.ContactDate descending, cn.InsertDate descending select new CaseNoteTreeItem { CaseNoteID = cn.CaseNoteID, NoteContactDate = Convert.ToDateTime(cn.ContactDate). ToShortDateString(), ParentNoteID = cn.ParentNote, InsertUser = cn.InsertUser, ContactDetailsPreview = cn.ContactDetails.Substring(0, 75) }; return caseNotesTree.ToList<CaseNoteTreeItem>(); } AND THIS ONE public static DataTable GetAllCNotes(int personID) { using (var context = MatrixDataContext.Create()) { var caseNotes = from cn in context.tblCaseNotes where cn.PersonID == personID orderby cn.ContactDate select new { cn.ContactDate, cn.ContactDetails, cn.TimeSpentUnits, cn.IsCaseLog, cn.IsPreEnrollment, cn.PresentAtContact, cn.InsertDate, cn.InsertUser, cn.CaseNoteID, cn.ParentNote }; return caseNotes.ToList().CopyLinqToDataTable(); } }

    Read the article

  • Phonegap (Cordova) iOS button click

    - by JNM
    I am trying to create a very simple phone gap application for iOS. I am using query mobile. the problem is, that i can't get javascript event to fire on button click. Code i have now: <!DOCTYPE html> <html> <head> <title>Title</title> <meta name="viewport" content="width=device-width, minimum-scale=1, maximum-scale=1"> <meta charset="utf-8"> <link rel="stylesheet" type="text/css" href="js/jquery.mobile-1.2.0.css" /> <script type="text/javascript" charset="utf-8" src="cordova-1.8.1.js"></script> <script type="text/javascript" charset="utf-8" src="js/jquery-1.8.2.min.js"></script> <script type="text/javascript" charset="utf-8" src="js/jquery.mobile-1.2.0.min.js"></script> <script type="text/javascript"> document.addEventListener("deviceready", onDeviceReady, false); function onDeviceReady() { } function showAlert() { navigator.notification.alert("Cordova is working"); } </script> </head> <body> <div data-role="page" id="options" data-add-back-btn="true" data-back-btn-text="Atgal"> <div data-role="header" data-position="fixed"> <h1>Title</h1> </div> <div data-role="content"> <h1>Alert</h1> <p><a href="#" onclick="showAlert(); return false;" data-role="button">Show alert</a></p> </div> </div> </body> </html> I tried multiple solutions to fix my problem, but none of them works. When have button with # in href, it doesn't event change the color on click. When i add url, it changes color. But it never call javascript function. Another problem is, that document.addEventListener("deviceready", onDeviceReady, false); works only in the index page. If i press button in initial page which redirects to another page, OnDeviceReady function is never called. Anybody has any ideas?

    Read the article

  • Please help with very simple android widget button click. Getting very frustrated. :(

    - by Little Wendy
    I have poured over every example that I can find and I have gone through the official documentation from google. All I am trying to do is create a toast notification from a button click on a widget. I can get the widget (and button) to appear but I can't get my intent to fire. I have seen several examples that show doing this different ways but I just can't get it to work. I haven't felt this helpless with coding in a long time and I'm starting to feel dumb. This is what I have so far: public class simpleclick extends AppWidgetProvider { /** Called when the activity is first created. */ @Override public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) { final int N = appWidgetIds.length; Toast.makeText(context, "doing on update", Toast.LENGTH_SHORT).show(); for (int i=0; i<N; i++) { int appWidgetId = appWidgetIds[i]; Intent intent = new Intent(context, simpleclick.class); intent.setAction("ham"); PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, intent, 0); RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.main); views.setOnClickPendingIntent(R.id.Timm, pendingIntent); appWidgetManager.updateAppWidget(appWidgetId, views); } } //@Override public void onReceive(Context context, Intent intent) { // TODO Auto-generated method stub Toast.makeText(context, "action is: " + intent.getAction(), Toast.LENGTH_SHORT).show(); super.onReceive(context, intent); } } My manifest: <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.tblabs.simpleclick" android:versionCode="1" android:versionName="1.0"> <application android:icon="@drawable/icon" android:label="@string/app_name"> <receiver android:name="simpleclick"> <intent-filter> <action android:name="android.appwidget.action.APPWIDGET_UPDATE" /> </intent-filter> <meta-data android:name="android.appwidget.provider" android:resource="@xml/simpleclick" /> </receiver> </application> <uses-sdk android:minSdkVersion="5" /> </manifest> I would appreciate some help! Thanks, Wendy

    Read the article

  • Freemarker rendering differently on IE8

    - by scphantm
    we have a template that uses this for the record line <input type="${inputType}" name="${variableName}.code" id="${variable}.${vnum}.${answer.code}" class="checkbox" value="${answer.code}" [#nested/] [#if (answer.textLength > 0) && scripting]onchange="showOtherBox( this, '${variable}.[#if descriptionHack]${variableNumber}[#else]${vnum}[/#if].${answer.code}.description' )"[/#if] [#if showValues && (existing == answer.code)]checked="checked"[/#if]/> On IE8 it renders as this <span class="field"> <INPUT id=responses.8.L class=checkbox value=L type=checkbox name="responses['8'].answers['L'].code"> <LABEL for=responses.8.L>Award(s) for special accomplishment or performance related to activity participation (please list)</LABEL> <TEXTAREA id=responses.8.L.description class=" visible" rows=4 cols=60 name="responses['8'].answers['L'].description"></TEXTAREA> </span> and on every other browser we tried, it renders as this <span class="field"> <input type="checkbox" name="responses['8'].answers['L'].code" id="responses.8.L" class="checkbox" value="L" onchange="showOtherBox( this, 'responses.8.L.description' )"> <label for="responses.8.L">Award(s) for special accomplishment or performance related to activity participation (please list)</label> <textarea rows="4" cols="60" name="responses['8'].answers['L'].description" id="responses.8.L.description" class="visible" classname="visible"></textarea> </span> The difference being that in the FTL script, the if statement [#if (answer.textLength > 0) && scripting] is true for everything except IE. In IE8 its false for some reason and therefore it does not put the OnChange javascript event on the input tag. Has anyone seen anything like this before? we are using Freemarker 2.3.9 Update, it kinda works if i turn compatibility mode on for IE8. but not exactly. when i do that, the onchange event doesn't fire until the check box loses focus. which is very different than everything else. Is there a quick way to fix this without too much trouble? i suppose i could put something in that says if ie8, insert onclick instead of onchange. that may work, but i would need an authorization from the client to fix it like that.

    Read the article

  • Can't get jQuery to get focus on cloned input fields

    - by Rebel1Moon
    I have a page that needs to create dynamic form fields as often as the user needs, and I am trying to use Ajax to tie it in to my database for faster form entry and to prevent user typos. So, I have put my Ajax returned data into popup div, the user selects, then the form field is filled in. The problem comes on the cloned fields. They don't seem to want to bring up the popup div when focused. I am thinking it is something to do with when they get created/added to the DOM. Here is my JS that creates the clones: $(document).ready(function() { var regex = /^(.*)(\d)+$/i; var cloneIndex = $(".clonedInput").length; $("button.clone").live("click", function(){ $(this).parents(".clonedInput").clone() .appendTo("#course_container") .attr("id", "clonedInput" + cloneIndex) .find("*").each(function() { var id = this.id || ""; var match = id.match(regex) || []; if (match.length == 3) { this.id = match[1] + (cloneIndex); } }); cloneIndex++; numClones=cloneIndex-1; //alert("numClones "+numClones); }); Here is where I expect to be able to get focus on the correct cloned field and call the popup. The baker_equiv0 id is original code, whereas baker_equiv1 is the first clone. $('#baker_equiv0').focus(function() { \\ THIS CODE WORKS $('.popup').fadeIn(500); $('#results').empty(); // document.enter_data.baker_equiv1.value="test"; THIS LINE WORKS //alert("numClones "+numClones); }); $('#baker_equiv1').focus(function() { // THIS DOESN'T EVER FIRE alert("numClones "+numClones); $('.popup').fadeIn(500); $('#results').empty(); }); Here is the HTML with the form: <label for="baker_equiv" class="">Baker Equivalent: <span class="requiredField">*</span></label> <input type="text" class="cinputsa" name="baker_equiv[]" id="baker_equiv0" size="8" ONKEYUP="get_equiv(this.value);"> If I put this in the HTML code above, it works fine: onfocus="alert(this.id)" I'd also be interested in how to adjust the JS code to work based on the id array created rather than having to copy code for each potential set of fields clones, i.e., baker_equiv[] rather than baker_equiv0, baker_equiv1, etc. Thanks all!

    Read the article

  • Problems with starting windows service on windows xp SP3

    - by Michiel Peeters
    I'm currently facing a problem which I can not resolve and I really don't know what to do anymore. When I'm trying to start the service I receive the message: "The service is started but again also stopped, this because that some of the services will stop if they have nothing to do, for example the performance logs and the alerts service". I've looked into the Windows Logs but nothing is written there which could describe why my service is all the time stopping. I've also tried to fire the windows service via the command prompt which gives me the message: "The service is not started, but the service didn't return any faults.". I've tried to remove all keys which references to my service, which didn't resolve the issue. I've searched on google (maybe not good enough) to find an answer but I didn't found any. I did found some websites which describes what I could do, but all of these suggestions didn't work. This is kinda ** because I do not know where to look. I do not have any error message, i do not have any id which i can use to search on. I really don't know where to start and I hope you guys can help me on this one. Detailed explanation about the windows service OS: Windows XP SP3 .Net Framework: .Net 4.0 Client Profile Language: C# Development environment: Visual Studio 2010 Professional (but Visual Studio 2012 RC is installed) Communications: WCF (Named Pipes), WCF (BasicHTTPBinding) Named Pipes: I have chosen for this solution because I wanted to communicate from a windows service to a windows form application. It worked now for quite some time but suddenly my windows service shuts it self down and I couldn't restart it anymore. There are two named pipes services implemented: An event service which will send any notification to the windows form application and an management service which gives my windows form application the possibility to maintain my windows service. BasicHTTPBinding: The basic http binding makes the connection to a central server. This connection is then used for streaming information from the client to the server. I do not know which additional information you will need, but if you guys need something then I'll try to give it as detailed as possible. Thank you in advance.

    Read the article

  • Cannot get document.getElementById() to find my textarea

    - by Slruh
    Maybe I've been working on my site for to long, but I can't get the following to work. I am having my textarea fire an onkeyup() event called limiter which is supposed to check the textarea and limit the text in the box, while updated another readonly input field that shows the amount of characters left. This is the javascript code: <script type="text/javascript"> var count = "500"; function limiter(){ var comment = document.getElementById("comment"); var form = this.parent; var tex = comment.value; var len = tex.length; if(len > count){ tex = tex.substring(0,count); comment.value =tex; return false; } form.limit.value = count-len; } </script> The form looks like this: <form id="add-course-rating" method="post" action="/course_ratings/add/8/3/5/3" accept- charset="utf-8"><div style="display:none;"><input type="hidden" name="_method" value="POST" /> //Other inputs here <div id="comment-name" style="margin-top:10px"> <div id="comment-name-text"> <b>Comments</b><br /> Please leave any comments that you think will help anyone else. </div> <style type="text/css"> .rating-form-box textarea { -moz-border-radius:5px 5px 5px 5px; } </style> <div class="rating-form-box"> <textarea name="data[CourseRatings][comment]" id="comment" onkeyup="limiter()" cols="115" rows="5" ></textarea> <script type="text/javascript"> document.write("<input type=text name=limit size=4 readonly value="+count+">"); </script> </div> <input type="submit" value="Add Rating" style="float: right;"> </form> If anyone can help that would be great.

    Read the article

  • Difficulty with jQuery and input keydown event

    - by Rosarch
    I am making a simple JavaScript enhanced list. I want it to be a list of inputs, each with an 'Add' and 'Remove' button. If the user clicks 'Add', a new li will be added. If the user clicks 'Remove', that li will be removed. It works fine, except for hitting "enter" in an <input>. Currently, it always causes the Remove.click event handler to fire, unless there's only one item in the list. I'm not sure why. How can I suppress this? Here is the complete jQuery. My attempt to fix the "enter" issue is commented out, and it doesn't work. I suspect that I could be designing this code better; if you see an improvement I'd love to hear it. function make_smart_list(list) { var ADD_CLASS = 'foo-widget-Add'; var REMOVE_CLASS = 'foo-widget-Remove'; var jq_list = $(list); jq_list.parents('form').submit(function() { return false; }); function refresh_handlers() { jq_list.find(sprintf('.%s, .%s', REMOVE_CLASS, ADD_CLASS)).unbind('click'); // jq_list.find('input').unbind('submit'); // // jq_list.find('input').submit(function() { // var jq_this = $(this); // var next_button = jq_this.nextAll('button'); // if (next_button.hasClass(ADD_CLASS)) { // next_button.nextAll('button').click(); // return; // } // // if (next_button.hasClass(REMOVE_CLASS)) { // return false; // } // // }); jq_list.find("." + REMOVE_CLASS).click(function() { var jq_this = $(this); jq_this.parent().remove(); refresh_handlers(); return false; }); jq_list.find("." + ADD_CLASS).click(function() { var jq_this = $(this); if (jq_this.prevAll('input').val() == '') { return; } jq_this.parent().clone().appendTo(jq_this.parent().parent()); jq_this.parent().next().find('input').val('').focus(); jq_this.removeClass(ADD_CLASS).addClass(REMOVE_CLASS); jq_this.text('Remove'); refresh_handlers(); return false; }); } refresh_handlers(); } (sprintf is another script I have.)

    Read the article

  • eth0 and eth1 both assigned same IP on boot

    - by Banjer
    I have a physical SLES 11 SP2 server on a Sun Fire x4140 that is giving me problems with networking upon reboot. The NICs are onboard. The networking appears successful during boot, but network services such as nfs fail hard. This is because eth0 and eth1 are both receiving the same configuration and are both ifup-ed. Once everything times out and I'm at the console, ifconfig shows that eth0 and eth1 are UP and running with the same IP. Attempting to ping anything in that subnet fails. Restarting the network service fixes the issue. eth0 is the correct NIC that should be configured as primary, per the MAC address. Question: Whats causing eth1 to be brought up with the same config as eth0?? I do not have a config script set up for eth1: banjer@harp:~> ls -la /etc/sysconfig/network/ total 104 drwxr-xr-x 6 root root 4096 Jun 11 12:21 . drwxr-xr-x 6 root root 4096 Apr 10 09:46 .. -rw-r--r-- 1 root root 13916 Apr 10 09:32 config -rw-r--r-- 1 root root 9952 Apr 10 09:36 dhcp -rw------- 1 root root 180 Jun 11 12:21 ifcfg-eth0 -rw------- 1 root root 180 Jun 11 12:21 ifcfg-eth3 -rw------- 1 root root 172 Feb 1 08:32 ifcfg-lo -rw-r--r-- 1 root root 29333 Feb 1 08:32 ifcfg.template drwxr-xr-x 2 root root 4096 Apr 10 09:32 if-down.d -rw-r--r-- 1 root root 239 Feb 1 08:32 ifroute-lo drwxr-xr-x 2 root root 4096 Apr 10 09:33 if-up.d drwx------ 2 root root 4096 May 5 2010 providers -rw-r--r-- 1 root root 25 Nov 16 2010 routes drwxr-xr-x 2 root root 4096 Apr 10 09:36 scripts On a side note, eth3 is also configured with an IP in a different subnet, but this has not posed any problems. FYI the kernel module being used is forcedeth. banjer@harp:~> sudo cat /etc/sysconfig/network/ifcfg-eth0 BOOTPROTO='static' BROADCAST='' ETHTOOL_OPTIONS='' IPADDR='172.21.64.25/20' MTU='' NAME='MCP55 Ethernet' NETWORK='' REMOTE_IPADDR='' STARTMODE='auto' USERCONTROL='no' ONBOOT="yes" Here's eth3 in case you need to see it: banjer@harp:~> sudo cat /etc/sysconfig/network/ifcfg-eth3 BOOTPROTO='static' BROADCAST='' ETHTOOL_OPTIONS='' IPADDR='172.11.200.4/24' MTU='' NAME='MCP55 Ethernet' NETWORK='' REMOTE_IPADDR='' STARTMODE='auto' USERCONTROL='no' ONBOOT="yes" Perhaps is something related to udev? 70-persistent-net-rules looks OK to me, but I may not understand it completely. banjer@harp:~> cat /etc/udev/rules.d/70-persistent-net.rules # This file was automatically generated by the /lib/udev/write_net_rules # program, run by the persistent-net-generator.rules rules file. # # You can modify it, as long as you keep each rule on a single # line, and change only the value of the NAME= key. # PCI device 0x10de:0x0373 (forcedeth) SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:18:4f:8d:85:4c", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth2" # PCI device 0x10de:0x0373 (forcedeth) SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:18:4f:8d:85:4a", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0" # PCI device 0x10de:0x0373 (forcedeth) SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:18:4f:8d:85:4b", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth1" # PCI device 0x10de:0x0373 (forcedeth) SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:18:4f:8d:85:4d", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth3" # PCI device 0x1077:0x3032 (qla3xxx) SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:c1:dd:0e:34:6c", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth4" Any other thoughts on what would cause this?

    Read the article

  • Troubleshooting PHP email sending?

    - by darkAsPitch
    I created a website that occasionally emails users when they register/change their password/etc. Every other person however cannot or does not receive the emails. They are telling me that they are not even hitting their spam folders. I don't know a ton about MX records or email sending, but when I "Edit DNS Zone" for this domain in particular there is 1 MX record listed there. How do you go about troubleshooting botched PHP mail actions? UPDATE: Here is my super-simple php mailing code: $subject = "Subject Here"; $message = "Emails Message"; $to = $verified_user_data["email_address"]; $headers = "From: [email protected]\r\n" . "Reply-To: [email protected]\r\n" . "X-Mailer: PHP/" . phpversion(); //returns true on success, false on failure $email_result = mail($to, $subject, $message, $headers); re: "are you saying that some do and some do not?" @ Jacob Yes, basically. I send the emails containing the user's login username/password using similar code above. And I sell to fairly tech-savvy people. About 50% of the time, my customers claim they cannot find their welcome emails in their inbox OR in their spam box. It's as if it never arrived. I have the largest problem with Yahoo email addresses accepting my emails or so it seems. re: "The MX record at your end doesn't factor in, although the SPF record (or lack of it) will. How much access and control do you have on the server itself?" @ John Gardeniers I rent a dedicated server from Codero. Running CentOS 5, WHM + cPanel. I have full root access to the entire thing. Don't know much about MX records and/or SPF records. I just want the PHP mail function to work. It doesn't say much about that on the php mail function's help page. re: "What are you using for the SMTP server?" @ JonLim No idea. I use the code above when I need to fire off an email to a loyal customer, and that's it. Do I need to be worrying about SMTP servers? re: "Could be many, many things. Can you describe how you're sending mail in your code? i.e. are you relaying off of another mail server somewhere, using the local sendmail or postfix? Any consistency in domains that can/cannot receive email? Do you have a PTR record setup from the IP address that you're sending mail out as? What about SPF records?" @ gravyface I just described my simple code above! I believe I have been having the most trouble with Yahoo domains, however "independent" domains (probably running spamassasin) ex. [email protected] as opposed to [email protected] seem to give a lot of trouble as well. I do not know if I have a PTR record setup from the IP address I'm sending my mail from. It's probably the same IP address that I setup my domain on, because I didn't do anything extra special. No idea about SPF records either, where can I go to create one? Side Note: It's a crying shame what havoc the spammers have brought upon our beloved email system.

    Read the article

  • set proxy in apache for XMPP chat

    - by Hunt
    I want to setup a proxy settings in Apache to use Facebook XMPP Chat So far I have setup ejabber server and I am able to access xmpp service using http://mydomain.com:5280/xmpp-http-bind I am able to create Jabber Account too. Now as I want to integrate Facebook XMPP chat , I want my server to sit in between client and chat.facebook.com because I want to implement Facebook chat and custom chat too. So I have read this article and come to know that I need to serve BOSH Service as a proxy in apache to access Facebook Chat service. So I don't know how to set up a proxy in a apache httpd.conf as I have tried following <Proxy *> Order deny,allow Allow from all </Proxy> ProxyPass /xmpp-httpbind http://www.mydomain.com:5280/xmpp-http-bind ProxyPassReverse /xmpp-httpbind http://www.mydomain.com:5280/xmpp-http-bind But whenever I request http://www.mydomain.com:5280/xmpp-http-bind from strophe.js I am getting following response from server <body type='terminate' condition='internal-server-error' xmlns='http://jabber.org/protocol/httpbind'> BOSH module not started </body> and server log says following E(<0.567.0:ejabberd_http_bind:1239) : You are trying to use BOSH (HTTP Bind) in host "chat.facebook.com", but the module mod_http_bind is not started in that host. Configure your BOSH client to connect to the correct host, or add your desired host to the configuration, or check your 'modules' section in your ejabberd configuration file. here is my existing settings of ejabberd.cfg , but still no luck {5280, ejabberd_http, [ {access,all}, {request_handlers, [ {["pub", "archive"], mod_http_fileserver}, {["xmpp-http-bind"], mod_http_bind} ]}, captcha, http_bind, http_poll, register, web_admin ]} ]}. in a module section {mod_http_bind, [{max_inactivity, 120}]}, and whenever i fire http://www.mydomain.com:5280/xmpp-http-bind url independently am getting following message ejabberd mod_http_bind An implementation of XMPP over BOSH (XEP-0206) This web page is only informative. To use HTTP-Bind you need a Jabber/XMPP client that supports it. I have added chat.facebook.com in a list of host in ejabber.cfg as follows {hosts, ["localhost","mydomain.com","chat.facebook.com"]} and now i am getting following response <body xmlns='http://jabber.org/protocol/httpbind' sid='710da2568460512eeb546545a65980c2704d9a27' wait='300' requests='2' inactivity='120' maxpause='120' polling='2' ver='1.8' from='chat.facebook.com' secure='true' authid='1917430584' xmlns:xmpp='urn:xmpp:xbosh' xmlns:stream='http://etherx.jabber.org/streams' xmpp:version='1.0'> <stream:features xmlns:stream='http://etherx.jabber.org/streams'> <mechanisms xmlns='urn:ietf:params:xml:ns:xmpp-sasl'> <mechanism>DIGEST-MD5</mechanism> <mechanism>PLAIN</mechanism> </mechanisms> <c xmlns='http://jabber.org/protocol/caps' hash='sha-1' node='http://www.process-one.net/en/ejabberd/' ver='yy7di5kE0syuCXOQTXNBTclpNTo='/> <register xmlns='http://jabber.org/features/iq-register'/> </stream:features> </body> if i use valid BOSH service created my jack moffit http://bosh.metajack.im:5280/xmpp-httpbind then i am getting following valid XML from facebook , but from my server i am not getting this <body xmlns='http://jabber.org/protocol/httpbind' inactivity='60' secure='true' authid='B8732AA1' content='text/xml; charset=utf-8' window='3' polling='15' sid='928073b02da55d34eb3c3464b4a40a37' requests='2' wait='300'> <stream:features xmlns:stream='http://etherx.jabber.org/streams' xmlns='jabber:client'> <mechanisms xmlns='urn:ietf:params:xml:ns:xmpp-sasl'> <mechanism>X-FACEBOOK-PLATFORM</mechanism> <mechanism>DIGEST-MD5</mechanism> </mechanisms> </stream:features> </body> Can anyone please help me to resolve the issue

    Read the article

  • Strange Upload Problem on Hyper-V

    - by Ring0
    Hi, This one is driving me totally nuts. I have being trying to upload a file to www.virustotal.com (its a harmless exe I have since found out - DiskWipe.exe from diskwipe.org). Using IE8. From Win 7 and Win 2008 R2 Datacenter (which I select to boot from vhd's) onto my main machine hardware, and also on another Win 7 PC elsewhere on my network, when I upload the file to virustotal.com it works perfectly. So, using my native NIC's everything is fine. Using another machine also perfect. Right. OK, from my boot menu the default is my main development machine - the one I'm typing on now. This runs on the metal and has Hyper-V role and I have some guests. All guests are not running. Amazingly, from my console (root partition to be exact) or any guest OS 2003 /XP / 2008 R2 etc. My upload to virustotal.com slows at 32% then HANGS at 38.something% & never finishes!! Here is the kicker. I have another box (my main server) running Hyper-V on the metal and three live guests. Identical H/W to my main dev machine in another room. (Except OS is Datacenter - Mine is Enterprise). If I try and upload from its bare metal console or any guest this file to virustotal.com using IE8 it stops exactly in the same place!! As for "steps I have tried etc." are kind-of blown out of the water as my server box is doing the precise same thing as the machine in my room here. OK, comonalities: Mobo: Gigabyte GA-X58-UD5, 12GB Kingston RAM, Corei7 920 4 cores hyperthreading = 8 & Realtek RTL8168D/8111D Family PCI-E Gigabit Ethernet NIC's. All 3 machines have this same motherboard - revision F11 Bios, all have 12GB RAM, all have the Realtek Nic's. All x64 by the way as I mentioned before I have a Win 7 box also with the UD5 m/Board, 12 GB RAM - bit of an overkill. :-) All these machines when NOT running Hyper-V can upload this file. Perhaps you may like to try it on a Hyepr-v (2008 R2) yourselves with IE8 and the desktop experience is on. See if it works or fails for you. Root OS or any guest. So, looking like its the NIC + Hyper-V = Cannot upload this file (any file I must add.) Realtek Nic is Ver 7.002.1125.2008. Using IE8 I see in the nic settings there are the usual parameters for Jumbo frames / Checksum offloading etc. several others. Should I fiddle with these? I ran Netmon 3.3 in a guest and the TCP session halted as the upload failed. I suppose I could study that further. I dont have Netmon on the root partition machine (yet)! All OS's fully patched - including todays defender files. My box running Office 2007 - but identical server in another room is not. Also, if I fire up a VPN to a distant client and do the upload it works! Of course its a different network path. Suggestions welcome please. If I left out anything important - please yell at me. Many Thanks,

    Read the article

  • ActiveX component can't create Object Error? Check 64 bit Status

    - by Rick Strahl
    If you're running on IIS 7 and a 64 bit operating system you might run into the following error using ASP classic or ASP.NET with COM interop. In classic ASP applications the error will show up as: ActiveX component can't create object   (Error 429) (actually without error handling the error just shows up as 500 error page) In my case the code that's been giving me problems has been a FoxPro COM object I'd been using to serve banner ads to some of my pages. The code basically looks up banners from a database table and displays them at random. The ASP classic code that uses it looks like this: <% Set banner = Server.CreateObject("wwBanner.aspBanner") banner.BannerFile = "wwsitebanners" Response.Write(banner.GetBanner(-1)) %> Originally this code had no specific error checking as above so the ASP pages just failed with 500 error pages from the Web server. To find out what the problem is this code is more useful at least for debugging: <% ON ERROR RESUME NEXT Set banner = Server.CreateObject("wwBanner.aspBanner") Response.Write(err.Number & " - " & err.Description) banner.BannerFile = "wwsitebanners" Response.Write(banner.GetBanner(-1)) %> which results in: 429 - ActiveX component can't create object which at least gives you a slight clue. In ASP.NET invoking the same COM object with code like this: <% dynamic banner = wwUtils.CreateComInstance("wwBanner.aspBanner") as dynamic; banner.cBANNERFILE = "wwsitebanners"; Response.Write(banner.getBanner(-1)); %> results in: Retrieving the COM class factory for component with CLSID {B5DCBB81-D5F5-11D2-B85E-00600889F23B} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)). The class is in fact registered though and the COM server loads fine from a command prompt or other COM client. This error can be caused by a COM server that doesn't load. It looks like a COM registration error. There are a number of traditional reasons why this error can crop up of course. The server isn't registered (run regserver32 to register a DLL server or /regserver on an EXE server) Access permissions aren't set on the COM server (Web account has to be able to read the DLL ie. Network service) The COM server fails to load during initialization ie. failing during startup One thing I always do to check for COM errors fire up the server in a COM client outside of IIS and ensure that it works there first - it's almost always easier to debug a server outside of the Web environment. In my case I tried the server in Visual FoxPro on the server with: loBanners = CREATEOBJECT("wwBanner.aspBanner") loBanners.cBannerFile = "wwsitebanners" ? loBanners.GetBanner(-1) and it worked just fine. If you don't have a full dev environment on the server you can also use VBScript do the same thing and run the .vbs file from the command prompt: Set banner = Server.CreateObject("wwBanner.aspBanner") banner.BannerFile = "wwsitebanners" MsgBox(banner.getBanner(-1)) Since this both works it tells me the server is registered and working properly. This leaves startup failures or permissions as the problem. I double checked permissions for the Application Pool and the permissions of the folder where the DLL lives and both are properly set to allow access by the Application Pool impersonated user. Just to be sure I assigned an Admin user to the Application Pool but still no go. So now what? 64 bit Servers Ahoy A couple of weeks back I had set up a few of my Application pools to 64 bit mode. My server is Server 2008 64 bit and by default Application Pools run 64 bit. Originally when I installed the server I set up most of my Application Pools to 32 bit mainly for backwards compatibility. But as more of my code migrates to 64 bit OS's I figured it'd be a good idea to see how well code runs under 64 bit code. The transition has been mostly painless. Until today when I noticed the problem with the code above when scrolling to my IIS logs and noticing a lot of 500 errors on many of my ASP classic pages. The code in question in most of these pages deals with this single simple COM object. It took a while to figure out that the problem is caused by the Application Pool running in 64 bit mode. The issue is that 32 bit COM objects (ie. my old Visual FoxPro COM component) cannot be loaded in a 64 bit Application Pool. The ASP pages using this COM component broke on the day I switched my main Application Pool into 64 bit mode but I didn't find the problem until I searched my logs for errors by pure chance. To fix this is easy enough once you know what the problem is by switching the Application Pool to Enable 32-bit Applications: Once this is done the COM objects started working correctly again. 64 bit ASP and ASP.NET with DCOM Servers This is kind of off topic, but incidentally it's possible to load 32 bit DCOM (out of process) servers from ASP.NET and ASP classic even if those applications run in 64 bit application pools. In fact, in West Wind Web Connection I use this capability to run a 64 bit ASP.NET handler that talks to a 32 bit FoxPro COM server which allows West Wind Web Connection to run in native 64 bit mode without custom configuration (which is actually quite useful). It's probably not a common usage scenario but it's good to know that you can actually access 32 bit COM objects this way from ASP.NET. For West Wind Web Connection this works out well as the DCOM interface only makes one non-chatty call to the backend server that handles all the rest of the request processing. Application Pool Isolation is your Friend For me the recent incident of failure in the classic ASP pages has just been another reminder to be very careful with moving applications to 64 bit operation. There are many little traps when switching to 64 bit that are very difficult to track and test for. I described one issue I had a couple of months ago where one of the default ASP.NET filters was loading the wrong version (32bit instead of 64bit) which was extremely difficult to track down and was caused by a very sneaky configuration switch error (basically 3 different entries for the same ISAPI filter all with different bitness settings). It took me almost a full day to track this down). Recently I've been taken to isolate individual applications into separate Application Pools rather than my past practice of combining many apps into shared AppPools. This is a good practice assuming you have enough memory to make this work. Application Pool isolate provides more modularity and allows me to selectively move applications to 64 bit. The error above came about precisely because I moved one of my most populous app pools to 64 bit and forgot about the minimal COM object use in some of my old pages. It's easy to forget. To 64bit or Not Is it worth it to move to 64 bit? Currently I'd say -not really. In my - admittedly limited - testing I don't see any significant performance increases. In fact 64 bit apps just seem to consume considerably more memory (30-50% more in my pools on average) and performance is minimally improved (less than 5% at the very best) in the load testing I've performed on a couple of sites in both modes. The only real incentive for 64 bit would be applications that require huge data spaces that exceed the 32 bit 4 gigabyte memory limit. However I have a hard time imagining an application that needs 4 gigs of memory in a single Application Pool :-). Curious to hear other opinions on benefits of 64 bit operation. © Rick Strahl, West Wind Technologies, 2005-2011Posted in COM   ASP.NET  FoxPro  

    Read the article

  • Android - creating a custom preferences activity screen

    - by Bill Osuch
    Android applications can maintain their own internal preferences (and allow them to be modified by users) with very little coding. In fact, you don't even need to write an code to explicitly save these preferences, it's all handled automatically! Create a new Android project, with an intial activity title Main. Create two more activities: ShowPrefs, which extends Activity Set Prefs, which extends PreferenceActivity Add these two to your AndroidManifest.xml file: <activity android:name=".SetPrefs"></activity> <activity android:name=".ShowPrefs"></activity> Now we'll work on fleshing out each activity. First, open up the main.xml layout file and add a couple of buttons to it: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="fill_parent"    android:layout_height="fill_parent"> <Button android:text="Edit Preferences"    android:id="@+id/prefButton"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_gravity="center_horizontal"/> <Button android:text="Show Preferences"    android:id="@+id/showButton"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_gravity="center_horizontal"/> </LinearLayout> Next, create a couple button listeners in Main.java to handle the clicks and start the other activities: Button editPrefs = (Button) findViewById(R.id.prefButton);       editPrefs.setOnClickListener(new View.OnClickListener() {              public void onClick(View view) {                  Intent myIntent = new Intent(view.getContext(), SetPrefs.class);                  startActivityForResult(myIntent, 0);              }      });           Button showPrefs = (Button) findViewById(R.id.showButton);      showPrefs.setOnClickListener(new View.OnClickListener() {              public void onClick(View view) {                  Intent myIntent = new Intent(view.getContext(), ShowPrefs.class);                  startActivityForResult(myIntent, 0);              }      }); Now, we'll create the actual preferences layout. You'll need to create a file called preferences.xml inside res/xml, and you'll likely have to create the xml directory as well. Add the following xml: <?xml version="1.0" encoding="utf-8"?> <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"> </PreferenceScreen> First we'll add a category, which is just a way to group similar preferences... sort of a horizontal bar. Add this inside the PreferenceScreen tags: <PreferenceCategory android:title="First Category"> </PreferenceCategory> Now add a Checkbox and an Edittext box (inside the PreferenceCategory tags): <CheckBoxPreference    android:key="checkboxPref"    android:title="Checkbox Preference"    android:summary="This preference can be true or false"    android:defaultValue="false"/> <EditTextPreference    android:key="editTextPref"    android:title="EditText Preference"    android:summary="This allows you to enter a string"    android:defaultValue="Nothing"/> The key is how you will refer to the preference in code, the title is the large text that will be displayed, and the summary is the smaller text (this will make sense when you see it). Let's say we've got a second group of preferences that apply to a different part of the app. Add a new category just below the first one: <PreferenceCategory android:title="Second Category"> </PreferenceCategory> In there we'll a list with radio buttons, so add: <ListPreference    android:key="listPref"    android:title="List Preference"    android:summary="This preference lets you select an item in a array"    android:entries="@array/listArray"    android:entryValues="@array/listValues" /> When complete, your full xml file should look like this: <?xml version="1.0" encoding="utf-8"?> <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">  <PreferenceCategory android:title="First Category"> <CheckBoxPreference    android:key="checkboxPref"    android:title="Checkbox Preference"    android:summary="This preference can be true or false"    android:defaultValue="false"/> <EditTextPreference    android:key="editTextPref"    android:title="EditText Preference"    android:summary="This allows you to enter a string"    android:defaultValue="Nothing"/>  </PreferenceCategory>  <PreferenceCategory android:title="Second Category">   <ListPreference    android:key="listPref"    android:title="List Preference"    android:summary="This preference lets you select an item in a array"    android:entries="@array/listArray"    android:entryValues="@array/listValues" />  </PreferenceCategory> </PreferenceScreen> However, when you try to save it, you'll get an error because you're missing your array definition. To fix this, add a file called arrays.xml in res/values, and paste in the following: <?xml version="1.0" encoding="utf-8"?> <resources>  <string-array name="listArray">      <item>Value 1</item>      <item>Value 2</item>      <item>Value 3</item>  </string-array>  <string-array name="listValues">      <item>1</item>      <item>2</item>      <item>3</item>  </string-array> </resources> Finally (for the preferences screen at least...) add the code that will display the preferences layout to the SetPrefs.java file:  @Override     public void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      addPreferencesFromResource(R.xml.preferences);      } OK, so now we've got an activity that will set preferences, and save them without the need to write custom save code. Let's throw together an activity to work with the saved preferences. Create a new layout called showpreferences.xml and give it three Textviews: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:orientation="vertical"     android:layout_width="fill_parent"     android:layout_height="fill_parent"> <TextView   android:id="@+id/textview1"     android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="textview1"/> <TextView   android:id="@+id/textview2"     android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="textview2"/> <TextView   android:id="@+id/textview3"     android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="textview3"/> </LinearLayout> Open up the ShowPrefs.java file and have it use that layout: setContentView(R.layout.showpreferences); Then add the following code to load the DefaultSharedPreferences and display them: SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);    TextView text1 = (TextView)findViewById(R.id.textview1); TextView text2 = (TextView)findViewById(R.id.textview2); TextView text3 = (TextView)findViewById(R.id.textview3);    text1.setText(new Boolean(prefs.getBoolean("checkboxPref", false)).toString()); text2.setText(prefs.getString("editTextPref", "<unset>"));; text3.setText(prefs.getString("listPref", "<unset>")); Fire up the application in the emulator and click the Edit Preferences button. Set various things, click the back button, then the Edit Preferences button again. Notice that your choices have been saved.   Now click the Show Preferences button, and you should see the results of what you set:   There are two more preference types that I did not include here: RingtonePreference - shows a radioGroup that lists your ringtones PreferenceScreen - allows you to embed a second preference screen inside the first - it opens up a new set of preferences when clicked

    Read the article

  • Replacing jQuery.live() with jQuery.on()

    - by Rick Strahl
    jQuery 1.9 and 1.10 have introduced a host of changes, but for the most part these changes are mostly transparent to existing application usage of jQuery. After spending some time last week with a few of my projects and going through them with a specific eye for jQuery failures I found that for the most part there wasn't a big issue. The vast majority of code continues to run just fine with either 1.9 or 1.10 (which are supposed to be in sync but with 1.10 removing support for legacy Internet Explorer pre-9.0 versions). However, one particular change in the new versions has caused me quite a bit of update trouble, is the removal of the jQuery.live() function. This is my own fault I suppose - .live() has been deprecated for a while, but with 1.9 and later it was finally removed altogether from jQuery. In the past I had quite a bit of jQuery code that used .live() and it's one of the things that's holding back my upgrade process, although I'm slowly cleaning up my code and switching to the .on() function as the replacement. jQuery.live() jQuery.live() was introduced a long time ago to simplify handling events on matched elements that exist currently on the document and those that are are added in the future and also match the selector. jQuery uses event bubbling, special event binding, plus some magic using meta data attached to a parent level element to check and see if the original target event element matches the selected selected elements (for more info see Elijah Manor's comment below). An Example Assume a list of items like the following in HTML for example and further assume that the items in this list can be appended to at a later point. In this app there's a smallish initial list that loads to start, and as the user scrolls towards the end of the initial small list more items are loaded dynamically and added to the list.<div id="PostItemContainer" class="scrollbox"> <div class="postitem" data-id="4z6qhomm"> <div class="post-icon"></div> <div class="postitemheader"><a href="show/4z6qhomm" target="Content">1999 Buick Century For Sale!</a></div> <div class="postitemprice rightalign">$ 3,500 O.B.O.</div> <div class="smalltext leftalign">Jun. 07 @ 1:06am</div> <div class="post-byline">- Vehicles - Automobiles</div> </div> <div class="postitem" data-id="2jtvuu17"> <div class="postitemheader"><a href="show/2jtvuu17" target="Content">Toyota VAN 1987</a></div> <div class="postitemprice rightalign">$950</div> <div class="smalltext leftalign">Jun. 07 @ 12:29am</div> <div class="post-byline">- Vehicles - Automobiles</div> </div> … </div> With the jQuery.live() function you could easily select elements and hook up a click handler like this:$(".postitem").live("click", function() {...}); Simple and perfectly readable. The behavior of the .live handler generally was the same as the corresponding simple event handlers like .click(), except that you have to explicitly name the event instead of using one of the methods. Re-writing with jQuery.on() With .live() removed in 1.9 and later we have to re-write .live() code above with an alternative. The jQuery documentation points you at the .on() or .delegate() functions to update your code. jQuery.on() is a more generic event handler function, and it's what jQuery uses internally to map the high level event functions like .click(),.change() etc. that jQuery exposes. Using jQuery.on() however is not a one to one replacement of the .live() function. While .on() can handle events directly and use the same syntax as .live() did, you'll find if you simply switch out .live() with .on() that events on not-yet existing elements will not fire. IOW, the key feature of .live() is not working. You can use .on() to get the desired effect however, but you have to change the syntax to explicitly handle the event you're interested in on the container and then provide a filter selector to specify which elements you are actually interested in for handling the event for. Sounds more complicated than it is and it's easier to see with an example. For the list above hooking .postitem clicks, using jQuery.on() looks like this:$("#PostItemContainer").on("click", ".postitem", function() {...}); You specify a container that can handle the .click event and then provide a filter selector to find the child elements that trigger the  the actual event. So here #PostItemContainer contains many .postitems, whose click events I want to handle. Any container will do including document, but I tend to use the container closest to the elements I actually want to handle the events on to minimize the event bubbling that occurs to capture the event. With this code I get the same behavior as with .live() and now as new .postitem elements are added the click events are always available. Sweet. Here's the full event signature for the .on() function: .on( events [, selector ] [, data ], handler(eventObject) ) Note that the selector is optional - if you omit it you essentially create a simple event handler that handles the event directly on the selected object. The filter/child selector required if you want life-like - uh, .live() like behavior to happen. While it's a bit more verbose than what .live() did, .on() provides the same functionality by being more explicit on what your parent container for trapping events is. .on() is good Practice even for ordinary static Element Lists As a side note, it's a good practice to use jQuery.on() or jQuery.delegate() for events in most cases anyway, using this 'container event trapping' syntax. That's because rather than requiring lots of event handlers on each of the child elements (.postitem in the sample above), there's just one event handler on the container, and only when clicked does jQuery drill down to find the matching filter element and tries to match it to the originating element. In the early days of jQuery I used manually build handlers that did this and manually drilled from the event object into the originalTarget to determine if it's a matching element. With later versions of jQuery the various event functions in jQuery essentially provide this functionality out of the box with functions like .on() and .delegate(). All of this is nothing new, but I thought I'd write this up because I have on a few occasions forgotten what exactly was needed to replace the many .live() function calls that litter my code - especially older code. This will be a nice reminder next time I have a memory blank on this topic. And maybe along the way I've helped one or two of you as well to clean up your .live() code…© Rick Strahl, West Wind Technologies, 2005-2013Posted in jQuery   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

    Read the article

  • MDI WinForm application and duplicate child form memory leak

    - by Steve
    This is a WinForm MDI application problem (.net framework 3.0). It will be described in C#. Sorry it is a bit long because I try to make things as clear as possible. I have a MDI application. At some point I find that one MDI child form is never released. There is a menu that creates the MDI child form and show it. When the MDI child form is closed, it is supposed to be destroyed and the memory taken by it should be given back to .net. But to my surprise, this is not true. All the MDI child form instances are kept in memory. This is obviously a "memory leak". Well, it is not a real leak in .net. It is just that I think the closed form should be dead but somehow there is at least one unknown reference from outside world that still connect with the closed form. I read some articles on the Web. Some says that when the MDI child form is closing, I should unwire all the event handlers, otherwise some event handlers may keep my form alive. Some says that DataBindings should be cleaned before the form is closing otherwise the DataBindings will add references to some global Hashtable and thus keep my form alive. My form contains quite a lot things. Many event handlers and many DataBindings and many BindingSources and few suspected controls containing user control and HelpProvider. I create a big method that unwires all the event handlers from all the relevant controls, clear all the DataBindings and DataSources. The HelpProvider and user controls are disposed carefully. At the end, I find that, I don't have to clear DataBindings and DataSources. Event handlers are definitely causing the problem. And MDI form structure also contributes to something. During my experiments, I find that, if you create a MDI child form, even if you close it, there will still be one instance in the memory. The reference is from PropertyStore of the main form. This means, unless the main form is closed (application ends), there will always be one instance of MDI child form in the memory. The good news is that, no matter how many times you open and close the child form, there will be only one instance, not a big "leak". When it comes to event handlers, things become more tricky. I have to address that, all the event handlers on my form are anonymous event handlers. Here is an example code: //On MDI child form's design code... Button btnSave = new Button(); btnSave.Click += new System.EventHandler(btnSave_Click); Where btnSave_Click is also a method in MDI child form. The above is always the case for various controls and various types of event. To me, this is a bi-directional circular reference. btnSave keeps a reference of MDI child form via the event handler. MDI child form keeps a reference of btnSave instance. To me again, such bi-directional circular reference should not cause any problem for .net's garbage collector. This means that I do not have to explicitly unwire the event when the form is being disposed: btnSave.Click -= btnSave_Click; But the truth is not so. For some event handlers, they are safe. Ignoring them do not cause any duplicate instance. For some other event handlers, they will cause one instance remaining in the memory (similar effect as the MDI form structure, but this time caused by the hanging event handlers). For some other event handlers, they will cause every instance opened in the memory. I am totally confused about the differences between these three types of event handlers. The controls are created in the same way and the event is attached in the same way. What is the difference? (Don't tell me it is the event handle methods that make difference.) Anyone has experience of this wired scenario and has an answer for me? Thanks a lot. So now, for safety issue, I will have to unwire all the event handlers when the form is being disposed. That will be a long list of similar code for each control. Is there a general way of removing events from controls in recursive way using reflection? What about performance issue? That's the end of my story and I am still in the middle of my problem. For any help, I thank you.

    Read the article

  • The Product Owner

    - by Robert May
    In a previous post, I outlined the rules of Scrum.  This post details one of those rules. Picking a most important part of Scrum is difficult.  All of the rules are required, but if there were one rule that is “more” required that every other rule, its having a good Product Owner.  Simply put, the Product Owner can make or break the project. Duties of the Product Owner A Product Owner has many duties and responsibilities.  I’ll talk about each of these duties in detail below. A Product Owner: Discovers and records stories for the backlog. Prioritizes stories in the Product Backlog, Release Backlog and Iteration Backlog. Determines Release dates and Iteration Dates. Develops story details and helps the team understand those details. Helps QA to develop acceptance tests. Interact with the Customer to make sure that the product is meeting the customer’s needs. Discovers and Records Stories for the Backlog When I do Scrum, I always use User Stories as the means for capturing functionality that’s required in the system.  Some people will use Use Cases, but the same rule applies.  The Product Owner has the ultimate responsibility for figuring out what functionality will be in the system.  Many different mechanisms for capturing this input can be used.  User interviews are great, but all sources should be considered, including talking with Customer Support types.  Often, they hear what users are struggling with the most and are a great source for stories that can make the application easier to use. Care should be taken when soliciting user stories from technical types such as programmers and the people that manage them.  They will almost always give stories that are very technical in nature and may not have a direct benefit for the end user.  Stories are about adding value to the company.  If the stories don’t have direct benefit to the end user, the Product Owner should question whether or not the story should be implemented.  In general, technical stories should be included as tasks in User Stories.  Technical stories are often needed, but the ultimate value to the user is in user based functionality, so technical stories should be considered nothing more than overhead in providing that user functionality. Until the iteration prior to development, stories should be nothing more than short, one line placeholders. An exercise called Story Planning can be used to brainstorm and come up with stories.  I’ll save the description of this activity for another blog post. For more information on User Stories, please read the book User Stories Applied by Mike Cohn. Prioritizes Stories in the Product Backlog, Release Backlog and Iteration Backlog Prioritization of stories is one of the most difficult tasks that a Product Owner must do.  A key concept of Scrum done right is the need to have the team working from a single set of prioritized stories.  If the team does not have a single set of prioritized stories, Scrum will likely fail at your organization.  The Product Owner is the ONLY person who has the responsibility to prioritize that list.  The Product Owner must be very diplomatic and sincerely listen to the people around him so that he can get the priorities correct. Just listening will still not yield the proper priorities.  Care must also be taken to ensure that Return on Investment is also considered.  Ultimately, determining which stories give the most value to the company for the least cost is the most important factor in determining priorities.  Product Owners should be willing to look at cold, hard numbers to determine the order for stories.  Even when many people want a feature, if that features is costly to develop, it may not have as high of a return on investment as features that are cheaper, but not as popular. The act of prioritization often causes conflict in an environment.  Customer Service thinks that feature X is the most important, because it will stop people from calling.  Operations thinks that feature Y is the most important, because it will stop servers from crashing.  Developers think that feature Z is most important because it will make writing software much easier for them.  All of these are useful goals, but the team can have only one list of items, and each item must have a priority that is different from all other stories.  The Product Owner will determine which feature gives the best return on investment and the other features will have to wait their turn, which means that someone will not have their top priority feature implemented first. A weak Product Owner will refuse to do prioritization.  I’ve heard from multiple Product Owners the following phrase, “Well, it’s all got to be done, so what does it matter what order we do it in?”  If your product owner is using this phrase, you need a new Product Owner.  Order is VERY important.  In Scrum, every release is potentially shippable.  If the wrong priority items are developed, then the value added in each release isn’t what it should be.  Additionally, the Product Owner with this mindset doesn’t understand Agile.  A product is NEVER finished, until the company has decided that it is no longer a going concern and they are no longer going to sell the product.  Therefore, prioritization isn’t an event, its something that continues every day.  The logical extension of the phrase “It’s all got to be done” is that you will never ship your product, since a product is never “done.”  Once stories have been prioritized, assigning them to the Release Backlog and the Iteration Backlog becomes relatively simple.  The top priority items are copied into the respective backlogs in order and the task is complete.  The team does have the right to shuffle things around a little in the iteration backlog.  For example, they may determine that working on story C with story A is appropriate because they’re related, even though story B is technically a higher priority than story C.  Or they may decide that story B is too big to complete in the time available after Story A has tasks created, so they’ll work on Story C since it’s smaller.  They can’t, however, go deep into the backlog to pick stories to implement.  The team and the Product Owner should work together to determine what’s best for the company. Prioritization is time consuming, but its one of the most important things a Product Owner does. Determines Release Dates and Iteration Dates Product owners are responsible for determining release dates for a product.  A common misconception that Product Owners have is that every “release” needs to correspond with an actual release to customers.  This is not the case.  In general, releases should be no more than 3 months long.  You  may decide to release the product to the customers, and many companies do release the product to customers, but it may also be an internal release. If a release date is too far away, developers will fall into the trap of not feeling a sense of urgency.  The date is far enough away that they don’t need to give the release their full attention.  Additionally, important tasks, such as performance tuning, regression testing, user documentation, and release preparation, will not happen regularly, making them much more difficult and time consuming to do.  The more frequently you do these tasks, the easier they are to accomplish. The Product Owner will be a key participant in determining whether or not a release should be sent out to the customers.  The determination should be made on whether or not the features contained in the release are valuable enough  and complete enough that the customers will see real value in the release.  Often, some features will take more than three months to get them to a state where they qualify for a release or need additional supporting features to be released.  The product owner has the right to make this determination. In addition to release dates, the Product Owner also will help determine iteration dates.  In general, an iteration length should be chosen and the team should follow that iteration length for an extended period of time.  If the iteration length is changed every iteration, you’re not doing Scrum.  Iteration lengths help the team and company get into a rhythm of developing quality software.  Iterations should be somewhere between 2 and 4 weeks in length.  Any shorter, and significant software will likely not be developed.  Any longer, and the team won’t feel urgency and planning will become very difficult. Iterations may not be extended during the iteration.  Companies where Scrum isn’t really followed will often use this as a strategy to complete all stories.  They don’t want to face the harsh reality of what their true performance is, and looking good is more important than seeking visibility and improving the process and team.  Companies like this typically don’t allow failure.  This is unhealthy.  Failure is part of life and unless we learn from it, we can’t improve.  I would much rather see a team push out stories to the next iteration and then have healthy discussions about why they failed rather than extend the iteration and not deal with the core problems. If iteration length varies, retrospectives become more difficult.  For example, evaluating the performance of the team’s estimation efforts becomes much more difficult if the iteration length varies.  Also, the team must have a velocity measurement.  If the iteration length varies, measuring velocity becomes impossible and upper management no longer will have the ability to evaluate the teams performance.  People external to the team will no longer have the ability to determine when key features are likely to be developed.  Variable iterations cause the entire company to fail and likely cause Scrum to fail at an organization. Develops Story Details and Helps the Team Understand Those Details A key concept in Scrum is that the stories are nothing more than a placeholder for a conversation.  Stories should be nothing more than short, one line statements about the functionality.  The team will then converse with the Product Owner about the details about that story.  The product owner needs to have a very good idea about what the details of the story are and needs to be able to help the team understand those details. Too often, we see this requirement as being translated into the need for comprehensive documentation about the story, including old fashioned requirements documentation.  The team should only develop the documentation that is required and should not develop documentation that is only created because their is a process to do so. In general, what we see that works best is the iteration before a team starts development work on a story, the Product Owner, with other appropriate business analysts, will develop the details of that story.  They’ll figure out what business rules are required, potentially make paper prototypes or other light weight mock-ups, and they seek to understand the story and what is implied.  Note that the time allowed for this task is deliberately short.  The Product Owner only has a single iteration to develop all of the stories for the next iteration. If more than one iteration is used, I’ve found that teams will end up with Big Design Up Front and traditional requirements documents.  This is a waste of time, since the team will need to then have discussions with the Product Owner to figure out what the requirements document says.  Instead of this, skip making the pretty pictures and detailing the nuances of the requirements and build only what is minimally needed by the team to do development.  If something comes up during development, you can address it at that time and figure out what you want to do.  The goal is to keep things as light weight as possible so that everyone can move as quickly as possible. Helps QA to Develop Acceptance Tests In Scrum, no story can be counted until it is accepted by QA.  Because of this, acceptance tests are very important to the team.  In general, acceptance tests need to be developed prior to the iteration or at the very beginning of the iteration so that the team can make sure that the tasks that they develop will fulfill the acceptance criteria. The Product Owner will help the team, including QA, understand what will make the story acceptable.  Note that the Product Owner needs to be careful about specifying that the feature will work “Perfectly” at the end of the iteration.  In general, features are developed a little bit at a time, so only the bit that is being developed should be considered as necessary for acceptance. A weak Product Owner will make statements like “Do it right the first time.”  Not only are these statements damaging to the team (like they would try to do it WRONG the first time . . .), they’re also ignoring the iterative nature of Scrum.  Additionally, a weak product owner will seek to add scope in the acceptance testing.  For example, they will refuse to determine acceptance at the beginning of the iteration, and then, after the team has planned and committed to the iteration, they will expand scope by defining acceptance.  This often causes the team to miss the iteration because scope that wasn’t planned on is included.  There are ways that the team can mitigate this problem.  For example, include extra “Product Owner” time to deal with the uncertainty that you know will be introduced by the Product Owner.  This will slow the perceived velocity of the team and is not ideal, since they’ll be doing more work than they get credit for. Interact with the Customer to Make Sure that the Product is Meeting the Customer’s Needs Once development is complete, what the team has worked on should be put in front of real live people to see if it meets the needs of the customer.  One of the great things about Agile is that if something doesn’t work, we can revisit it in a future iteration!  This frees up the team to make the best decision now and know that if that decision proves to be incorrect, the team can revisit it and change that decision. Features are about adding value to the customer, so if the customer doesn’t find them useful, then having the team make tweaks is valuable.  In general, most software will be 80 to 90 percent “right” after the initial round and only minor tweaks are required.  If proper coding standards are followed, these tweaks are usually minor and easy to accomplish.  Product Owners that are doing a good job will encourage real users to see and use the software, since they know that they are trying to add value to the customer. Poor product owners will think that they know the answers already, that their customers are silly and do stupid things and that they don’t need customer input.  If you have a product owner that is afraid to show the team’s work to real customers, you probably need a different product owner. Up Next, “Who Makes a Good Product Owner.” Followed by, “Messing with the Team.” Technorati Tags: Scrum,Product Owner

    Read the article

  • eBooks on iPad vs. Kindle: More Debate than Smackdown

    - by andrewbrust
    When the iPad was presented at its San Francisco launch event on January 28th, Steve Jobs spent a significant amount of time explaining how well the device would serve as an eBook reader. He showed the iBooks reader application and iBookstore and laid down the gauntlet before Amazon and its beloved Kindle device. Almost immediately afterwards, criticism came rushing forth that the iPad could never beat the Kindle for book reading. The curious part of that criticism is that virtually no one offering it had actually used the iPad yet. A few weeks later, on April 3rd, the iPad was released for sale in the United States. I bought one on that day and in the few additional weeks that have elapsed, I’ve given quite a workout to most of its capabilities, including its eBook features. I’ve also spent some time with the Kindle, albeit a first-generation model, to see how it actually compares to the iPad. I had some expectations going in, but I came away with conclusions about each device that were more scenario-based than absolute. I present my findings to you here.   Vital Statistics Let’s start with an inventory of each device’s underlying technology. The iPad has a color, backlit LCD screen and an on-screen keyboard. It has a battery which, on a full charge, lasts anywhere from 6-10 hours. The Kindle offers a monochrome, reflective E Ink display, a physical keyboard and a battery that on my first gen loaner unit can go up to a week between charges (Amazon claims the battery on the Kindle 2 can last up to 2 weeks on a single charge). The Kindle connects to Amazon’s Kindle Store using a 3G modem (the technology and network vary depending on the model) that incurs no airtime service charges whatsoever. The iPad units that are on-sale today work over WiFi only. 3G-equipped models will be on sale shortly and will command a $130 premium over their WiFi-only counterparts. 3G service on the iPad, in the U.S. from AT&T, will be fee-based, with a 250MB plan at $14.99 per month and an unlimited plan at $29.99. No contract is required for 3G service. All these tech specs aside, I think a more useful observation is that the iPad is a multi-purpose Internet-connected entertainment device, while the Kindle is a dedicated reading device. The question is whether those differences in design and intended use create a clear-cut winner for reading electronic publications. Let’s take a look at each device, in isolation, now.   Kindle To me, what’s most innovative about the Kindle is its E Ink display. E Ink really looks like ink on a sheet of paper. It requires no backlight, it’s fully visible in direct sunlight and it causes almost none of the eyestrain that LCD-based computer display technology (like that used on the iPad) does. It’s really versatile in an all-around way. Forgive me if this sounds precious, but reading on it is really a joy. In fact, it’s a genuinely relaxing experience. Through the Kindle Store, Amazon allows users to download books (including audio books), magazines, newspapers and blog feeds. Books and magazines can be purchased either on a single-issue basis or as an annual subscription. Books, of course, are purchased singly. Oddly, blogs are not free, but instead carry a monthly subscription fee, typically $1.99. To me this is ludicrous, but I suppose the free 3G service is partially to blame. Books and magazine issues download quickly. Magazine and blog subscriptions cause new issues or posts to be pushed to your device on an automated basis. Available blogs include 9000-odd feeds that Amazon offers on the Kindle Store; unless I missed something, arbitrary RSS feeds are not supported (though there are third party workarounds to this limitation). The shopping experience is integrated well, has an huge selection, and offers certain graphical perks. For example, magazine and newspaper logos are displayed in menus, and book cover thumbnails appear as well. A simple search mechanism is provided and text entry through the physical keyboard is relatively painless. It’s very easy and straightforward to enter the store, find something you like and start reading it quickly. If you know what you’re looking for, it’s even faster. Given Kindle’s high portability, very reliable battery, instant-on capability and highly integrated content acquisition, it makes reading on whim, and in random spurts of downtime, very attractive. The Kindle’s home screen lists all of your publications, and easily lets you select one, then start reading it. Once opened, publications display in crisp, attractive text that is adjustable in size. “Turning” pages is achieved through buttons dedicated to the task. Notes can be recorded, bookmarks can be saved and pages can be saved as clippings. I am not an avid book reader, and yet I found the Kindle made it really fun, convenient and soothing to read. There’s something about the easy access to the material and the simplicity of the display that makes the Kindle seduce you into chilling out and reading page after page. On the other hand, the Kindle has an awkward navigation interface. While menus are displayed clearly on the screen, the method of selecting menu items is tricky: alongside the right-hand edge of the main display is a thin column that acts as a second display. It has a white background, and a scrollable silver cursor that is moved up or down through the use of the device’s scrollwheel. Picking a menu item on the main display involves scrolling the silver cursor to a position parallel to that menu item and pushing the scrollwheel in. This navigation technique creates a disconnect, literally. You don’t really click on a selection so much as you gesture toward it. I got used to this technique quickly, but I didn’t love it. It definitely created a kind of anxiety in me, making me feel the need to speed through menus and get to my destination document quickly. Once there, I could calm down and relax. Books are great on the Kindle. Magazines and newspapers much less so. I found the rendering of photographs, and even illustrations, to be unacceptably crude. For this reason, I expect that reading textbooks on the Kindle may leave students wanting. I found that the original flow and layout of any publication was sacrificed on the Kindle. In effect, browsing a magazine or newspaper was almost impossible. Reading the text of individual articles was enjoyable, but having to read this way made the whole experience much more “a la carte” than cohesive and thematic between articles. I imagine that for academic journals this is ideal, but for consumer publications it imposes a stripped-down, low-fidelity experience that evokes a sense of deprivation. In general, the Kindle is great for reading text. For just about anything else, especially activity that involves exploratory browsing, meandering and short-attention-span reading, it presents a real barrier to entry and adoption. Avid book readers will enjoy the Kindle (if they’re not already). It’s a great device for losing oneself in a book over long sittings. Multitaskers who are more interested in periodicals, be they online or off, will like it much less, as they will find compromise, and even sacrifice, to be palpable.   iPad The iPad is a very different device from the Kindle. While the Kindle is oriented to pages of text, the iPad orbits around applications and their interfaces. Be it the pinch and zoom experience in the browser, the rich media features that augment content on news and weather sites, or the ability to interact with social networking services like Twitter, the iPad is versatile. While it shares a slate-like form factor with the Kindle, it’s effectively an elegant personal computer. One of its many features is the iBook application and integration of the iBookstore. But it’s a multi-purpose device. That turns out to be good and bad, depending on what you’re reading. The iBookstore is great for browsing. It’s color, rich animation-laden user interface make it possible to shop for books, rather than merely search and acquire them. Unfortunately, its selection is rather sparse at the moment. If you’re looking for a New York Times bestseller, or other popular titles, you should be OK. If you want to read something more specialized, it’s much harder. Unlike the awkward navigation interface of the Kindle, the iPad offers a nearly flawless touch-screen interface that seduces the user into tinkering and kibitzing every bit as much as the Kindle lulls you into a deep, concentrated read. It’s a dynamic and interactive device, whereas the Kindle is static and passive. The iBook reader is slick and fun. Use the iPad in landscape mode and you can read the book in 2-up (left/right 2-page) display; use it in portrait mode and you can read one page at a time. Rather than clicking a hardware button to turn pages, you simply drag and wipe from right-to-left to flip the single or right-hand page. The page actually travels through an animated path as it would in a physical book. The intuitiveness of the interface is uncanny. The reader also accommodates saving of bookmarks, searching of the text, and the ability to highlight a word and look it up in a dictionary. Pages display brightly and clearly. They’re easy to read. But the backlight and the glare made me less comfortable than I was with the Kindle. The knowledge that completely different applications (including the Web and email and Twitter) were just a few taps away made me antsy and very tempted to task-switch. The knowledge that battery life is an issue created subtle discomfort. If the Kindle makes you feel like you’re in a library reading room, then the iPad makes you feel, at best, like you’re under fluorescent lights at a Barnes and Noble or Borders store. If you’re lucky, you’d be on a couch or at a reading table in the store, but you might also be standing up, in the aisles. Clearly, I didn’t find this conducive to focused and sustained reading. But that may have more to do with my own tendency to read periodicals far more than books, and my neurotic . And, truth be known, the book reading experience, when not explicitly compared to Kindle’s, was still pleasant. It is also important to point out that Kindle Store-sourced books can be read on the iPad through a Kindle reader application, from Amazon, specific to the device. This offered a less rich experience than the iBooks reader, but it was completely adequate. Despite the Kindle brand of the reader, however, it offered little in terms of simulating the reading experience on its namesake device. When it comes to periodicals, the iPad wins hands down. Magazines, even if merely scanned images of their print editions, read on the iPad in a way that felt similar to reading hard copy. The full color display, touch navigation and even the ability to render advertisements in their full glory makes the iPad a great way to read through any piece of work that is measured in pages, rather than chapters. There are many ways to get magazines and newspapers onto the iPad, including the Zinio reader, and publication-specific applications like the Wall Street Journal’s and Popular Science’s. The New York Times’ free Editors’ Choice application offers a Times Reader-like interface to a subset of the Gray Lady’s daily content. The completely Web-based but iPad-optimized Times Skimmer site (at www.nytimes.com/timesskimmer) works well too. Even conventional Web sites themselves can be read much like magazines, given the iPad’s ability to zoom in on the text and crop out advertisements on the margins. While the Kindle does have an experimental Web browser, it reminded me a lot of early mobile phone browsers, only in a larger size. For text-heavy sites with simple layout, it works fine. For just about anything else, it becomes more trouble than it’s worth. And given the way magazine articles make me think of things I want to look up online, I think that’s a real liability for the Kindle.   Summing Up What I came to realize is that the Kindle isn’t so much a computer or even an Internet device as it is a printer. While it doesn’t use physical paper, it still renders its content a page at a time, just like a laser printer does, and its output appears strikingly similar. You can read the rendered text, but you can’t interact with it in any way. That’s why the navigation requires a separate cursor display area. And because of the page-oriented rendering behavior, turning pages causes a flash on the display and requires a sometimes long pause before the next page is rendered. The good side of this is that once the page is generated, no battery power is required to display it. That makes for great battery life, optimal viewing under most lighting conditions (as long as there is some light) and low-eyestrain text-centric display of content. The Kindle is highly portable, has an excellent selection in its store and is refreshingly distraction-free. All of this is ideal for reading books. And iPad doesn’t offer any of it. What iPad does offer is versatility, variety, richness and luxury. It’s flush with accoutrements even if it’s low on focused, sustained text display. That makes it inferior to the Kindle for book reading. But that also makes it better than the Kindle for almost everything else. As such, and given that its book reading experience is still decent (even if not superior), I think the iPad will give Kindle a run for its money. True book lovers, and people on a budget, will want the Kindle. People with a robust amount of discretionary income may want both devices. Everyone else who is interested in a slate form factor e-reading device, especially if they also wish to have leisure-friendly Internet access, will likely choose the iPad exclusively. One thing is for sure: iPad has reduced Kindle’s market, and may have shifted its mass market potential to a mere niche play. If Amazon is smart, it will improve its iPad-based Kindle reader app significantly. It can then leverage the iPad channel as a significant market for the Kindle Store. After all, selling the eBooks themselves is what Amazon should care most about.

    Read the article

  • Is Berkeley DB a NoSQL solution?

    - by Gregory Burd
    Berkeley DB is a library. To use it to store data you must link the library into your application. You can use most programming languages to access the API, the calls across these APIs generally mimic the Berkeley DB C-API which makes perfect sense because Berkeley DB is written in C. The inspiration for Berkeley DB was the DBM library, a part of the earliest versions of UNIX written by AT&T's Ken Thompson in 1979. DBM was a simple key/value hashtable-based storage library. In the early 1990s as BSD UNIX was transitioning from version 4.3 to 4.4 and retrofitting commercial code owned by AT&T with unencumbered code, it was the future founders of Sleepycat Software who wrote libdb (aka Berkeley DB) as the replacement for DBM. The problem it addressed was fast, reliable local key/value storage. At that time databases almost always lived on a single node, even the most sophisticated databases only had simple fail-over two node solutions. If you had a lot of data to store you would choose between the few commercial RDBMS solutions or to write your own custom solution. Berkeley DB took the headache out of the custom approach. These basic market forces inspired other DBM implementations. There was the "New DBM" (ndbm) and the "GNU DBM" (GDBM) and a few others, but the theme was the same. Even today TokyoCabinet calls itself "a modern implementation of DBM" mimicking, and improving on, something first created over thirty years ago. In the mid-1990s, DBM was the name for what you needed if you were looking for fast, reliable local storage. Fast forward to today. What's changed? Systems are connected over fast, very reliable networks. Disks are cheep, fast, and capable of storing huge amounts of data. CPUs continued to follow Moore's Law, processing power that filled a room in 1990 now fits in your pocket. PCs, servers, and other computers proliferated both in business and the personal markets. In addition to the new hardware entire markets, social systems, and new modes of interpersonal communication moved onto the web and started evolving rapidly. These changes cause a massive explosion of data and a need to analyze and understand that data. Taken together this resulted in an entirely different landscape for database storage, new solutions were needed. A number of novel solutions stepped up and eventually a category called NoSQL emerged. The new market forces inspired the CAP theorem and the heated debate of BASE vs. ACID. But in essence this was simply the market looking at what to trade off to meet these new demands. These new database systems shared many qualities in common. There were designed to address massive amounts of data, millions of requests per second, and scale out across multiple systems. The first large-scale and successful solution was Dynamo, Amazon's distributed key/value database. Dynamo essentially took the next logical step and added a twist. Dynamo was to be the database of record, it would be distributed, data would be partitioned across many nodes, and it would tolerate failure by avoiding single points of failure. Amazon did this because they recognized that the majority of the dynamic content they provided to customers visiting their web store front didn't require the services of an RDBMS. The queries were simple, key/value look-ups or simple range queries with only a few queries that required more complex joins. They set about to use relational technology only in places where it was the best solution for the task, places like accounting and order fulfillment, but not in the myriad of other situations. The success of Dynamo, and it's design, inspired the next generation of Non-SQL, distributed database solutions including Cassandra, Riak and Voldemort. The problem their designers set out to solve was, "reliability at massive scale" so the first focal point was distributed database algorithms. Underneath Dynamo there is a local transactional database; either Berkeley DB, Berkeley DB Java Edition, MySQL or an in-memory key/value data structure. Dynamo was an evolution of local key/value storage onto networks. Cassandra, Riak, and Voldemort all faced similar design decisions and one, Voldemort, choose Berkeley DB Java Edition for it's node-local storage. Riak at first was entirely in-memory, but has recently added write-once, append-only log-based on-disk storage similar type of storage as Berkeley DB except that it is based on a hash table which must reside entirely in-memory rather than a btree which can live in-memory or on disk. Berkeley DB evolved too, we added high availability (HA) and a replication manager that makes it easy to setup replica groups. Berkeley DB's replication doesn't partitioned the data, every node keeps an entire copy of the database. For consistency, there is a single node where writes are committed first - a master - then those changes are delivered to the replica nodes as log records. Applications can choose to wait until all nodes are consistent, or fire and forget allowing Berkeley DB to eventually become consistent. Berkeley DB's HA scales-out quite well for read-intensive applications and also effectively eliminates the central point of failure by allowing replica nodes to be elected (using a PAXOS algorithm) to mastership if the master should fail. This implementation covers a wide variety of use cases. MemcacheDB is a server that implements the Memcache network protocol but uses Berkeley DB for storage and HA to replicate the cache state across all the nodes in the cache group. Google Accounts, the user authentication layer for all Google properties, was until recently running Berkeley DB HA. That scaled to a globally distributed system. That said, most NoSQL solutions try to partition (shard) data across nodes in the replication group and some allow writes as well as reads at any node, Berkeley DB HA does not. So, is Berkeley DB a "NoSQL" solution? Not really, but it certainly is a component of many of the existing NoSQL solutions out there. Forgetting all the noise about how NoSQL solutions are complex distributed databases when you boil them down to a single node you still have to store the data to some form of stable local storage. DBMs solved that problem a long time ago. NoSQL has more to do with the layers on top of the DBM; the distributed, sometimes-consistent, partitioned, scale-out storage that manage key/value or document sets and generally have some form of simple HTTP/REST-style network API. Does Berkeley DB do that? Not really. Is Berkeley DB a "NoSQL" solution today? Nope, but it's the most robust solution on which to build such a system. Re-inventing the node-local data storage isn't easy. A lot of people are starting to come to appreciate the sophisticated features found in Berkeley DB, even mimic them in some cases. Could Berkeley DB grow into a NoSQL solution? Absolutely. Our key/value API could be extended over the net using any of a number of existing network protocols such as memcache or HTTP/REST. We could adapt our node-local data partitioning out over replicated nodes. We even have a nice query language and cost-based query optimizer in our BDB XML product that we could reuse were we to build out a document-based NoSQL-style product. XML and JSON are not so different that we couldn't adapt one to work with the other interchangeably. Without too much effort we could add what's missing, we could jump into this No SQL market withing a single product development cycle. Why isn't Berkeley DB already a NoSQL solution? Why aren't we working on it? Why indeed...

    Read the article

  • Visiting the Emtel Data Centre

    Back in February at the first event of the Emtel Knowledge Series (EKS) I spoke to various people at Emtel about their data centre here on the island. I was trying to see whether it would be possible to arrange a meeting over there for a selected group of our community members. Well, let's say it like this... My first approach wasn't that promising and far from successful but during the following months there were more and more occasions to get in touch with the "right" contact persons at Emtel to make it happen... Setting up an appointment and pre-requisites The major improvement came during a Boot Camp for Windows Phone 8.1 App development organised by Microsoft Indian Ocean Islands in cooperation with Emtel at the Emtel World, Ebene. Apart from learning bits and pieces regarding Universal Apps I took the opportunity to get in touch with Arvin Lockee, Sales Executive - Data, during our lunch break. And this really kicked off the whole procedure. Prior to get access to the Emtel data centre it is requested that you provide full name and National ID of anyone going to visit. Also, it should be noted that there was only a limited amount of seats available. Anyways, packed with this information I posted through the usual social media channels. Responses came in very quickly and based on First-come, first-serve (FCFS) principle I noted down the details and forwarded them to Emtel in order to fix a date and time for the visit. In preparation on our side, all attendees exchanged contact details and we organised transport options to go to the data centre in Arsenal. The day before and on the day of our meeting, Arvin send me a reminder to check whether everything is still confirmed and ready to go... Of course, it was! Arriving at the Emtel Data Centre As I'm coming from Flic En Flac towards the North, we agreed that I'm going to pick up a couple of young fellows near the old post office in Port Louis. All went well, except that Sean eventually might be living in another time zone compared to the rest of us. Anyway, after some extended stop we were complete and arrived just in time in Arsenal to meet and greet with Ish and Veer. Again, Emtel is taking access procedures to their data centre very serious and the gate stayed close until all our IDs had been noted and compared to the list of registered attendees. Despite having a good laugh at the mixture of old and new ID cards it was a straight-forward processing. The ward was very helpful and guided us to the waiting area at the entrance section of the building. Shortly after we were welcomed by Kamlesh Bokhoree, the Data Centre Officer. He gave us brief introduction into the rules and regulations during our visit, like no photography allowed, not touching the buttons, and following his instructions through the whole visit. Of course! Inside the data centre Next, he explained us the multi-factor authentication system using a combination of bio-metric data, like finger print reader, and "classic" pin panel. The Emtel data centre provides multiple services and next to co-location for your own hardware they also offer storage options for your backup and archive data in their massive, fire-resistant vault. Very impressive to get to know about the considerations that have been done in choosing the right location and how to set up the whole premises. It should also be noted that there is 24/7 CCTV surveillance inside and outside the buildings. Strengths of the Emtel TIER 3 Data Centre, Mauritius Finally, we were guided into the first server room. And wow, the whole setup is cleverly planned and outlined in the architecture. From the false floor and ceilings in order to provide optimum air flow, over to the separation of cold and hot aisles between the full-size server racks, and of course the monitored air conditions in order to analyse and watch changes in temperature, smoke detection and other parameters. And not surprisingly everything has been implemented in two independent circuits. There is a standardised classification for the construction and operation of data centres world-wide, and the Emtel's one has been designed to be a TIER 4 building but due to the lack of an alternative power supplier on the island it is officially registered as a TIER 3 compliant data centre. Maybe in the long run there might be a second supplier of energy next to CEB... time will tell. Luckily, the data centre is integrated into the National Fibre Optic Gigabit Ring and Emtel already connects internationally through diverse undersea cable routes like SAFE & LION/LION2 out of Mauritius and through several other providers for onwards connectivity. The data centre is part of the National Fibre Optic Gigabit Ring and has redundant internet connectivity onwards. Meanwhile, Arvin managed to join our little group of geeks and he supported Kamlesh in answering our technical questions regarding the capacities and general operation of the data centre. Visiting the NOC and its dedicated team of IT professionals was surely one of the visual highlights. Seeing their wall of screens to monitor any kind of activities on the data lines, the managed servers and the activity in and around the building was great. Even though I'm using a multi-head setup since years I cannot keep it up with that setup... ;-) But I got a couple of ideas on how to improve my work spaces here at the office. Clear advantages of hosting your e-commerce and mobile backends locally After the completely isolated NOC area we continued our Q&A session with Kamlesh and Arvin in the second server room which is dedictated to shared environments. On first thought it should be well-noted that there is lots of space for full-sized racks and therefore co-location of your own hardware. Actually, given the feedback that there will be upcoming changes in prices the facilities at the Emtel data centre are getting more and more competitive and interesting for local companies, especially small and medium enterprises. After seeing this world-class infrastructure available on the island, I'm already considering of moving one of my root servers abroad to be co-located here on the island. This would provide an improved user experience in terms of site performance and latency. This would be a good improvement, especially for upcoming e-commerce solutions for two of my local clients. Later on, we actually started the conversation of additional services that could be a catalyst for the local market in order to attract more small and medium companies to take the data centre into their evaluations regarding online activities. Until today Emtel does not provide virtualised server environments but there might be ongoing plans in the future to cover this field as well. Emtel is a mobile operator and internet connectivity provider in the first place, entering a market of managed and virtualised server infrastructures including capacities in terms of cloud storage and computing are rather new and there is a continuous learning curve at Emtel, too. You cannot just jump into a new market and see how it works out... And I appreciate Emtel's approach towards a solid fundament and then building new services on top of that. Emtel as a future one-stop-shop service provider for all your internet and telecommunications needs. Emtel's promotional video about their TIER 3 data centre in Arsenal, Mauritius More details are thoroughly described in Emtel's brochure of their data centre. Check out their PDF document here. Thanks for this opportunity Visiting and walking through the Emtel data centre for more than 2 hours was a great experience. As representative of the Mauritius Software Craftsmanship Community (MSCC) I would like to thank anyone at Emtel involved in the process of making it happen, and especially to Arvin Lockee and Kamlesh Bokhoree for their time and patience in explaining the infrastructure and answering all the endless questions from our members. Thank You!

    Read the article

  • Using Radio Button in GridView with Validation

    - by Vincent Maverick Durano
    A developer is asking how to select one radio button at a time if the radio button is inside the GridView.  As you may know setting the group name attribute of radio button will not work if the radio button is located within a Data Representation control like GridView. This because the radio button inside the gridview bahaves differentely. Since a gridview is rendered as table element , at run time it will assign different "name" to each radio button. Hence you are able to select multiple rows. In this post I'm going to demonstrate how select one radio button at a time in gridview and add a simple validation on it. To get started let's go ahead and fire up visual studio and the create a new web application / website project. Add a WebForm and then add gridview. The mark up would look something like this: <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" > <Columns> <asp:TemplateField> <ItemTemplate> <asp:RadioButton ID="rb" runat="server" /> </ItemTemplate> </asp:TemplateField> <asp:BoundField DataField="RowNumber" HeaderText="Row Number" /> <asp:BoundField DataField="Col1" HeaderText="First Column" /> <asp:BoundField DataField="Col2" HeaderText="Second Column" /> </Columns> </asp:GridView> Noticed that I've added a templatefield column so that we can add the radio button there. Also I have set up some BoundField columns and set the DataFields as RowNumber, Col1 and Col2. These columns are just dummy columns and i used it for the simplicity of this example. Now where these columns came from? These columns are created by hand at the code behind file of the ASPX. Here's the code below: private DataTable FillData() { DataTable dt = new DataTable(); DataRow dr = null; //Create DataTable columns dt.Columns.Add(new DataColumn("RowNumber", typeof(string))); dt.Columns.Add(new DataColumn("Col1", typeof(string))); dt.Columns.Add(new DataColumn("Col2", typeof(string))); //Create Row for each columns dr = dt.NewRow(); dr["RowNumber"] = 1; dr["Col1"] = "A"; dr["Col2"] = "B"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 2; dr["Col1"] = "AA"; dr["Col2"] = "BB"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 3; dr["Col1"] = "A"; dr["Col2"] = "B"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 4; dr["Col1"] = "A"; dr["Col2"] = "B"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 5; dr["Col1"] = "A"; dr["Col2"] = "B"; dt.Rows.Add(dr); return dt; } And here's the code for binding the GridView with the dummy data above. protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { GridView1.DataSource = FillData(); GridView1.DataBind(); } } Okay we have now a GridView data with a radio button on each row. Now lets go ahead and switch back to ASPX mark up. In this example I'm going to use a JavaScript for validating the radio button to select one radio button at a time. Here's the javascript code below: function CheckOtherIsCheckedByGVID(rb) { var isChecked = rb.checked; var row = rb.parentNode.parentNode; if (isChecked) { row.style.backgroundColor = '#B6C4DE'; row.style.color = 'black'; } var currentRdbID = rb.id; parent = document.getElementById("<%= GridView1.ClientID %>"); var items = parent.getElementsByTagName('input'); for (i = 0; i < items.length; i++) { if (items[i].id != currentRdbID && items[i].type == "radio") { if (items[i].checked) { items[i].checked = false; items[i].parentNode.parentNode.style.backgroundColor = 'white'; items[i].parentNode.parentNode.style.color = '#696969'; } } } } The function above sets the row of the current selected radio button's style to determine that the row is selected and then loops through the radio buttons in the gridview and then de-select the previous selected radio button and set the row style back to its default. You can then call the javascript function above at onlick event of radio button like below: <asp:RadioButton ID="rb" runat="server" onclick="javascript:CheckOtherIsCheckedByGVID(this);" /> Here's the output below: On Load: After Selecting a Radio Button: As you have noticed, on initial load there's no default selected radio in the GridView. Now let's add a simple validation for that. We will basically display an error message if a user clicks a button that triggers a postback without selecting  a radio button in the GridView. Here's the javascript for the validation: function ValidateRadioButton(sender, args) { var gv = document.getElementById("<%= GridView1.ClientID %>"); var items = gv.getElementsByTagName('input'); for (var i = 0; i < items.length ; i++) { if (items[i].type == "radio") { if (items[i].checked) { args.IsValid = true; return; } else { args.IsValid = false; } } } } The function above loops through the rows in gridview and find all the radio buttons within it. It will then check each radio button checked property. If a radio is checked then set IsValid to true else set it to false.  The reason why I'm using IsValid is because I'm using the ASP validator control for validation. Now add the following mark up below under the GridView declaration: <br /> <asp:Label ID="lblMessage" runat="server" /> <br /> <asp:Button ID="btn" runat="server" Text="POST" onclick="btn_Click" ValidationGroup="GroupA" /> <asp:CustomValidator ID="CustomValidator1" runat="server" ErrorMessage="Please select row in the grid." ClientValidationFunction="ValidateRadioButton" ValidationGroup="GroupA" style="display:none"></asp:CustomValidator> <asp:ValidationSummary ID="ValidationSummary1" runat="server" ValidationGroup="GroupA" HeaderText="Error List:" DisplayMode="BulletList" ForeColor="Red" /> And then at Button Click event add this simple code below just to test if  the validation works: protected void btn_Click(object sender, EventArgs e) { lblMessage.Text = "Postback at: " + DateTime.Now.ToString("hh:mm:ss tt"); } Here's the output below that you can see in the browser:   That's it! I hope someone find this post useful! Technorati Tags: ASP.NET,JavaScript,GridView

    Read the article

  • WP7 Tips–Part I– Media File Coding Techniques to help pass the Windows Phone 7 Marketplace Certification Requirements

    - by seaniannuzzi
    Overview Developing an application that plays media files on a Windows Phone 7 Device seems fairly straight forward.  However, what can make this a bit frustrating are the necessary requirements in order to pass the WP7 marketplace requirements so that your application can be published.  If you are new to this development, be aware of these common challenges that are likely to be made.  Below are some techniques and recommendations on how optimize your application to handle playing MP3 and/or WMA files that needs to adhere to the marketplace requirements.   Windows Phone 7 Certification Requirements Windows Phone 7 Developers Blog   Some common challenges are: Not prompting the user if another media file is playing in the background before playing your media file Not allowing the user to control the volume Not allowing the user to mute the sound Not allowing the media to be interrupted by a phone call  To keep this as simple as possible I am only going to focus on what “not to do” and what “to do” in order to implement a simple media solution. Things you will need or may be useful to you before you begin: Visual Studio 2010 Visual Studio 2010 Feature Packs Windows Phone 7 Developer Tools Visual Studio 2010 Express for Windows Phone Windows Phone Emulator Resources Silverlight 4 Tools For Visual Studio XNA Game Studio 4.0 Microsoft Expression Blend for Windows Phone Note: Please keep in mind you do not need all of these downloaded and installed, it is just easier to have all that you need now rather than add them on later.   Objective Summary Create a Windows Phone 7 – Windows Media Sample Application.  The application will implement many of the required features in order to pass the WP7 marketplace certification requirements in order to publish an application to WP7’s marketplace. (Disclaimer: I am not trying to indicate that this application will always pass as the requirements may change or be updated)   Step 1: – Create a New Windows Phone 7 Project   Step 2: – Update the Title and Application Name of your WP7 Application For this example I changed: the Title to: “DOTNETNUZZI WP7 MEDIA SAMPLE - v1.00” and the Page Title to:  “media magic”. Note: I also updated the background.   Step 3: – XAML - Media Element Preparation and Best Practice Before we begin the next step I just wanted to point out a few things that you should not do as a best practice when developing an application for WP7 that is playing music.  Please keep in mind that these requirements are not the same if you are playing Sound Effects and are geared towards playing media in the background.   If you have coded this – be prepared to change it:   To avoid a failure from the market place remove all of your media source elements from your XAML or simply create them dynamically.  To keep this simple we will remove the source and set the AutoPlay property to false to ensure that there are no media elements are active when the application is started. Proper example of the media element with No Source:   Some Additional Settings - Add XAML Support for a Mute Button   Step 4: – Boolean to handle toggle of Mute Feature Step 5: – Add Event Handler for Main Page Load   Step 6: – Add Reference to the XNA Framework   Step 7: – Add two Using Statements to Resolve the Namespace of Media and the Application Bar using Microsoft.Xna.Framework.Media; using Microsoft.Phone.Shell;   Step 8: – Add the Method to Check the Media State as Shown Below   Step 9: – Add Code to Mute the Media File Step 10: – Add Code to Play the Media File //if the state of the media has been checked you are good to go. media_sample.Play(); Note: If we tried to perform this operation at this point you will receive the following error: System.InvalidOperationException was unhandled Message=FrameworkDispatcher.Update has not been called. Regular FrameworkDispatcher.Update calls are necessary for fire and forget sound effects and framework events to function correctly. See http://go.microsoft.com/fwlink/?LinkId=193853 for details. StackTrace:        at Microsoft.Xna.Framework.FrameworkDispatcher.AddNewPendingCall(ManagedCallType callType, UInt32 arg)        at Microsoft.Xna.Framework.UserAsyncDispatcher.HandleManagedCallback(ManagedCallType managedCallType, UInt32 managedCallArgs) at Microsoft.Xna.Framework.UserAsyncDispatcher.AsyncDispatcherThreadFunction()            It is not recommended that you just add the FrameworkDispatcher.Update(); call before playing the media file. It is recommended that you implement the following class to your solution and implement this class in the app.xaml.cs file.   Step 11: – Add FrameworkDispatcher Features I recommend creating a class named XNAAsyncDispatcher and adding the following code:   After you have added the code accordingly, you can now implement this into your app.xaml.cs file as highlighted below.   Note:  If you application sound file is not playing make sure you have the proper “Build Action” set such as Content.   Running the Sample Now that we have some of the foundation created you should be able to run the application successfully.  When the application launches your sound options should be set accordingly when the “checkMediaState” method is called.  As a result the application will properly setup the media options and/or alert the user accordinglyper the certification requirements.  In addition, the sample also shows a quick way to mute the sound in your application by simply removing the URI source of the media file.  If everything successfully compiled the application should look similar to below.                 <sound playing>   Summary At this point we have a fully functional application that provides techniques on how to avoid some common challenges when working with media files and developing applications for Windows Phone 7.  The techniques mentioned above should make things a little easier and helpful in getting your WP7 application approved and published on the Marketplace.  The next blog post will be titled: WP7 Tips–Part II - How to write code that will pass the Windows Phone 7 Marketplace Requirements for Themes (light and dark). If anyone has any questions or comments please comment on this blog. 

    Read the article

  • Wrapping ASP.NET Client Callbacks

    - by Ricardo Peres
    Client Callbacks are probably the less known (and I dare say, less loved) of all the AJAX options in ASP.NET, which also include the UpdatePanel, Page Methods and Web Services. The reason for that, I believe, is it’s relative complexity: Get a reference to a JavaScript function; Dynamically register function that calls the above reference; Have a JavaScript handler call the registered function. However, it has some the nice advantage of being self-contained, that is, doesn’t need additional files, such as web services, JavaScript libraries, etc, or static methods declared on a page, or any kind of attributes. So, here’s what I want to do: Have a DOM element which exposes a method that is executed server side, passing it a string and returning a string; Have a server-side event that handles the client-side call; Have two client-side user-supplied callback functions for handling the success and error results. I’m going to develop a custom control without user interface that does the registration of the client JavaScript method as well as a server-side event that can be hooked by some handler on a page. My markup will look like this: 1: <script type="text/javascript"> 1:  2:  3: function onCallbackSuccess(result, context) 4: { 5: } 6:  7: function onCallbackError(error, context) 8: { 9: } 10:  </script> 2: <my:CallbackControl runat="server" ID="callback" SendAllData="true" OnCallback="OnCallback"/> The control itself looks like this: 1: public class CallbackControl : Control, ICallbackEventHandler 2: { 3: #region Public constructor 4: public CallbackControl() 5: { 6: this.SendAllData = false; 7: this.Async = true; 8: } 9: #endregion 10:  11: #region Public properties and events 12: public event EventHandler<CallbackEventArgs> Callback; 13:  14: [DefaultValue(true)] 15: public Boolean Async 16: { 17: get; 18: set; 19: } 20:  21: [DefaultValue(false)] 22: public Boolean SendAllData 23: { 24: get; 25: set; 26: } 27:  28: #endregion 29:  30: #region Protected override methods 31:  32: protected override void Render(HtmlTextWriter writer) 33: { 34: writer.AddAttribute(HtmlTextWriterAttribute.Id, this.ClientID); 35: writer.RenderBeginTag(HtmlTextWriterTag.Span); 36:  37: base.Render(writer); 38:  39: writer.RenderEndTag(); 40: } 41:  42: protected override void OnInit(EventArgs e) 43: { 44: String reference = this.Page.ClientScript.GetCallbackEventReference(this, "arg", "onCallbackSuccess", "context", "onCallbackError", this.Async); 45: String script = String.Concat("\ndocument.getElementById('", this.ClientID, "').callback = function(arg, context, onCallbackSuccess, onCallbackError){", ((this.SendAllData == true) ? "__theFormPostCollection.length = 0; __theFormPostData = ''; WebForm_InitCallback(); " : String.Empty), reference, ";};\n"); 46:  47: this.Page.ClientScript.RegisterStartupScript(this.GetType(), String.Concat("callback", this.ClientID), script, true); 48:  49: base.OnInit(e); 50: } 51:  52: #endregion 53:  54: #region Protected virtual methods 55: protected virtual void OnCallback(CallbackEventArgs args) 56: { 57: EventHandler<CallbackEventArgs> handler = this.Callback; 58:  59: if (handler != null) 60: { 61: handler(this, args); 62: } 63: } 64:  65: #endregion 66:  67: #region ICallbackEventHandler Members 68:  69: String ICallbackEventHandler.GetCallbackResult() 70: { 71: CallbackEventArgs args = new CallbackEventArgs(this.Context.Items["Data"] as String); 72:  73: this.OnCallback(args); 74:  75: return (args.Result); 76: } 77:  78: void ICallbackEventHandler.RaiseCallbackEvent(String eventArgument) 79: { 80: this.Context.Items["Data"] = eventArgument; 81: } 82:  83: #endregion 84: } And the event argument class: 1: [Serializable] 2: public class CallbackEventArgs : EventArgs 3: { 4: public CallbackEventArgs(String argument) 5: { 6: this.Argument = argument; 7: this.Result = String.Empty; 8: } 9:  10: public String Argument 11: { 12: get; 13: private set; 14: } 15:  16: public String Result 17: { 18: get; 19: set; 20: } 21: } You will notice two properties on the CallbackControl: Async: indicates if the call should be made asynchronously or synchronously (the default); SendAllData: indicates if the callback call will include the view and control state of all of the controls on the page, so that, on the server side, they will have their properties set when the Callback event is fired. The CallbackEventArgs class exposes two properties: Argument: the read-only argument passed to the client-side function; Result: the result to return to the client-side callback function, set from the Callback event handler. An example of an handler for the Callback event would be: 1: protected void OnCallback(Object sender, CallbackEventArgs e) 2: { 3: e.Result = String.Join(String.Empty, e.Argument.Reverse()); 4: } Finally, in order to fire the Callback event from the client, you only need this: 1: <input type="text" id="input"/> 2: <input type="button" value="Get Result" onclick="document.getElementById('callback').callback(callback(document.getElementById('input').value, 'context', onCallbackSuccess, onCallbackError))"/> The syntax of the callback function is: arg: some string argument; context: some context that will be passed to the callback functions (success or failure); callbackSuccessFunction: some function that will be called when the callback succeeds; callbackFailureFunction: some function that will be called if the callback fails for some reason. Give it a try and see if it helps!

    Read the article

< Previous Page | 119 120 121 122 123 124 125 126 127 128 129 130  | Next Page >