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best practices question: How to save a collection of images and a java object in a single file? File

- by Richard

Hi all, I am making a java program that has a collection of flash-card like objects. I store the objects in a jtree composed of defaultmutabletreenodes. Each node has a user object attached to it with has a few string/native data type parameters. However, i also want each of these objects to have an image (typical formats, jpg, png etc). I would like to be able to store all of this information, including the images and the tree data to the disk in a single file so the file can be transferred between users and the entire tree, including the images and parameters for each object, can be reconstructed. I had not approached a problem like this before so I was not sure what the best practices were. I found XLMEncoder (http://java.sun.com/j2se/1.4.2/docs/api/java/beans/XMLEncoder.html) to be a very effective way of storing my tree and the native data type information. However I couldn't figure out how to save the image data itself inside of the XML file, and I'm not sure it is possible since the data is binary (so restricted characters would be invalid). My next thought was to associate a hash string instead of an image within each user object, and then gzip together all of the images, with the hash strings as the names and the XMLencoded tree in the same compmressed file. That seemed really contrived though. Does anyone know a good approach for this type of issue? THanks! Thanks!

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EFv1 mapping 1 to many Relationship to POCOs

- by Scott

I'm trying to work through a problem where I'm mapping EF Entities to POCO which serve as DTO. I have two tables within my database, say Products and Categories. A Product belongs to one category and one category may contain many Products. My EF entities are named efProduct and efCategory. Within each entity there is the proper Navigation Property between efProduct and efCategory. My Poco objects are simple public class Product { public string Name { get; set; } public int ID { get; set; } public double Price { get; set; } public Category ProductType { get; set; } } public class Category { public int ID { get; set; } public string Name { get; set; } public List<Product> products { get; set; } } To get a list of products I am able to do something like public IQueryable<Product> GetProducts() { return from p in ctx.Products select new Product { ID = p.ID, Name = p.Name, Price = p.Price ProductType = p.Category }; } However there is a type mismatch error because p.Category is of type efCategory. How can I resolve this? That is, how can I convert p.Category to type Category? I know in .NET EF has added support for POCO, but I'm forced to use .NET 3.5 SP1.

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Is this the only way to pass a parameter for Cakephp to work with JQuery Ajax

- by kwokwai

Hi all, I was doing some self-learning on how to pass data from JQuery Ajax to a particular URL in CakePHP: I have tested three sets of codes that the first one was working well, but the rest failed to work, which makes me so confused. Could some experts here tell why the second and the third sets of codes failed to pass any data? Set 1: <input type=text name="data[User][name]" id="data[User][name]" size="36" maxlength="36"/> var usr = $("#data\\[User\\]\\[name\\]").val(); $.post( "http://www.washington.byethost18.com/site1/toavail/"+usr, function(msg){alert(msg);} ); Set 2: <input type=text name="data[User][name]" id="data[User][name]" size="36" maxlength="36"/> var usr = $("#data\\[User\\]\\[name\\]").val(); $.post( "http://www.washington.byethost18.com/site1/toavail/", {queryString: ""+usr+""}, function(msg){alert(msg);} ); Set 3: <input type=text name="data[User][name]" id="data[User][name]" size="36" maxlength="36"/> var usr = $("#data\\[User\\]\\[name\\]").val(); $.post( "http://www.washington.byethost18.com/site1/toavail/", usr, function(msg){alert(msg);} );

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Javascript autocomplete function href

- by user896692

I´ve the following javascript-function: <script type="text/javascript"> $(function() { var data = (<?php include("php/search_new.php"); ?>).Data.Recipes; var source = []; for (var i in data) { source.push({"href": "/php/get_recipe_byID.php?id=" + data[i].ID, "label": data[i].TITLE}); } $("#searchrecipes").autocomplete({ minLength: 3, source: source, select: function(event, ui) { window.location.href = ui.item.href; } }); }); </script> <input id="searchrecipes" type="text" name="searchrecipes" style="margin-left: 850px; margin-top: 0px; width:170px; background: #fff url(images/search_icon.png) no-repeat 100%;" onblur="this.style.background='#ffffff'; background: #fff url(images/search_icon.png) no-repeat 100%;" onfocus="this.style.background='#c40606'; background: url(images/search_icon.png) no-repeat 100%;" placeholder="Suchen..."></input> <input type="submit" name="buttonsenden" style="display:none;" value="" width: 5px></input> The function has already worked but suddenly it stopped working. The problem is, that the href on the dropdown-autocomplete isn´t clickable. var data = ({"Data":{"Recipes":{"Recipe_5":{"ID":"5","TITLE":"Spaghetti Bolognese"},"Recipe_7":{"ID":"7","TITLE":"Wurstel"},"Recipe_9":{"ID":"9","TITLE":"Schnitzel"},"Recipe_10":{"ID":"10","TITLE":null},"Recipe_19":{"ID":"19","TITLE":null},"Recipe_20":{"ID":"20","TITLE":"Hundefutter"},"Recipe_26":{"ID":"26","TITLE":"Apfelstrudel"},"Recipe_37":{"ID":"37","TITLE":null},"Recipe_38":{"ID":"38","TITLE":"AENDERUNG"},"Recipe_39":{"ID":"39","TITLE":null},"Recipe_40":{"ID":"40","TITLE":"Schnitzel"},"Recipe_42":{"ID":"42","TITLE":"Release-Test"},"Recipe_43":{"ID":"43","TITLE":"Wurstel2"}}},"Message":null,"Code":200}).Data.Recipes; All the necessary jquery scripts are available. What can be the problem?

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formatting mysql data for ouptut into a table

- by bsandrabr

Following on from a question earlier today this answer was given to read the data into an array and separate it to print vehicle type and then some data for each vehicle. <?php $sql = "SELECT * FROM apparatus ORDER BY vehicleType"; $getSQL = mysql_query($sql); // transform the result set: $data = array(); while ($row = mysql_fetch_assoc($getSQL)) { $data[$row['vehicleType']][] = $row; } ?> <?php foreach ($data as $type => $rows): ?> <h2><?php echo $type?></h2> <ul> <?php foreach ($rows as $vehicleData):?> <li><?php echo $vehicleData['name'];?></li> <?php endforeach ?> </ul> <?php endforeach ?> This is almost perfect for what I want to do but I need to print out two columns from the database ie ford and mondeo before going into the second foreach loop. I've tried print $rows['model'] and all the other combinations I can think of but that doesn't work. Any help much appreciated

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How can a <label> completely fill its parent <td>?

- by Shawn

Here is the relevant code (doesn't work): <html> <head> <title>testing td checkboxes</title> <style type="text/css"> td { border: 1px solid #000; } label { border: 1px solid #f00; width: 100%; height: 100% } </style> </head> <body> <table> <tr><td>Some column title</td><td>Another column title</td></tr> <tr><td>Value 1<br>(a bit more info)</td><td><label><input type="checkbox" />  </label></td></tr> <tr><td>Value 2</td><td><input type="checkbox" /></td></tr> </table> </body> </html> The reason is that I want a click anywhere in the table cell to check/uncheck the checkbox.

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Pulling name value pair from a structured adsense code block contained in a txt file

- by Scott B

I have a txt file which contains a google adsense code block and I'm trying to pull in the file via file_get_contents to extract the values of the google_ad_client and google_ad_slot variables. In the examples below, I want to return to my calling function: $google_ad_client = 'pub-1234567890987654'; $google_ad_slot = '1234567890' The file may contain one of either of these two formats and I wont know which the user has chosen: Newer Ad Unit Style <script type="text/javascript"> </script> <script type="text/javascript" src="path-to-google-script"></script> Classic Style <script type="text/javascript"> </script>

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Problem with inheritance and List<>

- by Jagd

I have an abstract class called Grouping. I have a subclass called GroupingNNA. public class GroupingNNA : Grouping { // blah blah blah } I have a List that contains items of type GroupingNNA, but is actually declared to contain items of type Grouping. List<Grouping> lstGroupings = new List<Grouping>(); lstGroupings.Add( new GroupingNNA { fName = "Joe" }); lstGroupings.Add( new GroupingNNA { fName = "Jane" }); The Problem: The following LINQ query blows up on me because of the fact that lstGroupings is declared as List< Grouping and fName is a property of GroupingNNA, not Grouping. var results = from g in lstGroupings where r.fName == "Jane" select r; Oh, and this is a compiler error, not a runtime error. Thanks in advance for any help on this one! More Info: Here is the actual method that won't compile. The OfType() fixed the LINQ query, but the compiler doesn't like the fact that I'm trying to return the anonymous type as a List< Grouping. private List<Grouping> ApplyFilterSens(List<Grouping> lstGroupings, string fSens) { // This works now! Thanks @Lasse var filtered = from r in lstGroupings.OfType<GroupingNNA>() where r.QASensitivity == fSens select r; if (filtered != null) { **// Compiler doesn't like this now** return filtered.ToList<Grouping>(); } else return new List<Grouping>(); }

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How to pass a parameter in a Javascript confirm function?

- by Miles M.

I have something like that in my code: <?php foreach($clients as $client): ?> <tr class="tableContent"> <td onclick="location.href='<?php echo site_url('clients/edit/'.$client->id ) ?>'"><?php echo $client->id ?></td> <td><a class='Right btn btn-danger' onClick="ConfirmMessage('client', <?php $client->id ?>,'clients')"> <i class="icon-remove-sign icon-white"></i> </a></td> </tr> <?php endforeach ?> that's actually the view. So when the user click on the delete button (thr one with the btn-danger class) I'd like him to confirm his choice with a javascript confirmation box message. You can find that script in the header <script> function ConfirmMessage(type, id, types) { if (confirm("Are you sure you want to delete this ",type," ?")) { // Clic sur OK document.location.href='<?php echo site_url(); ?>',types,'/delete/',id; } } </script> So here is my question: I would like the $type to be replaced by a paramenter (like client, article, post .. ) that I'll pass to the function. And i would like to get the $client-id parameter as well. I'm bad in javascript and as you already have guess, It is obviously not working at all.

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Multiple jQuery includes in a document

- by bah

Hi, I have a document which uses old jQuery and I need new jQuery for a particular plug-in. My document structure looks like this: <html> <head> <script type="text/javascript" src="jQuery.old.js"></script> </head> <body> <script> $("#elem").doSomething(); // use old jQuery </script>  <script type="text/javascript" src="jQuery.new.js"></script> <script type="text/javascript" src="jQuery.doSomething.js"></script> <script> $().ready(function(){ $("#elem").doSomething(); // use new jQuery }); </script> <div id="elem"></div>  <script> $("#elem").doSomething(); // use old jQuery </script> </body> </html> I have googled for this question but found nothing that would look like my case (I need first to load old javascript (in the head) and THEN new (in the body). By the way, in the Firefox looks like old jQuery lib loads and scripts that depends on it works, but script that uses new version, and in IE and Chrome everything is exactly opposite.

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Using $.post for simple ajax test, what am I missing?

- by Cortopasta

Playing with jquery for the first time, and I'm trying to get a simple AJAX set up working so I can better understand how things work. Unfortunately, I don't know a whole lot. Here's the HTML with the script: <html> <head> <title>AJAX attempt with jQuery</title> <script type="text/javascript" src="jquery.js"></script> <script type="text/javascript"> function ajax(str){ $("document").ready(function(){ $.post("ajaxjquerytest.php",str,function(){ $("p").html(response); }); }); </script> </head> <body> <input type="text" onchange="ajax(this.value)"></input> <p>Age?</p> </body> </html> And here is the PHP it's talking to: <?php $age = $_POST['age']; if ($age < 30) { echo "Young"; } else if ($age > 30) { echo "Old"; } else { echo "you're 30"; } ?>

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comparing value with array value problem Javascript

- by Java starter

This code is what I use now, it dos not work when I trie to use an array to compate values. If anybody has any idea of why, please respond. <html> <head> <script type-'text/javascript'> function hovedFunksjon() { //alert("test av funksjon fungerte"); //alert(passordLager); window.open("index10.html","Window1","menubar=no,width=430,height=360,toolbar=no"); } function inArray(array, value) { for (var i = 0; i < array.length; i++) { if (array[i] == value) return true; } return false; } function spørOmPassord() { var passordLager = ["pass0","pass1","pass2"]; window.passordInput = prompt("password");//Ved å bruke "window." skaper man en global variabel //if (passordInput == passordLager[0] || passordLager[1] || passordLager[2]) if (inArray(passordLager,passorInput) ) { hovedFunksjon(); } else { alert("Feil passord"); //href="javascript:self.close()">close window } } function changeBackgroundColor() { //document.bgColor="#CC9900"; //document.bgColor="YELLOW" document.bgColor="BLACK" } </script> </head> <body> <script type-'text/javascript'> changeBackgroundColor(); </script> <div align="center"> <form> <input type = "button" value = "Logg inn" onclick="spørOmPassord()"> </form> </div> </body> </html>

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Strange numbers in java socket output

- by user293163

I have small test app: Socket socket = new Socket("jeck.ru", 80); PrintWriter pw = new PrintWriter(socket.getOutputStream(), false); pw.println("GET /ip/ HTTP/1.1"); pw.println("Host: jeck.ru"); pw.println(); pw.flush(); BufferedReader rd = new BufferedReader(new InputStreamReader(socket.getInputStream())); String str; while ((str = rd.readLine()) != null) { System.out.println(str); } It`s output: HTTP/1.1 200 OK Date: Sat, 13 Mar 2010 22:06:51 GMT Content-Type: text/html;charset=utf-8 Transfer-Encoding: chunked Connection: keep-alive Keep-Alive: timeout=5 Server HTTP/1.1 200 OK Date: Sat, 13 Mar 2010 22:06:51 GMT Content-Type: text/html;charset=utf-8 Transfer-Encoding: chunked Connection: keep-alive Keep-Alive: timeout=5 Server: Apache Cache-Control: max-age=0 Expires: Sat, 13 Mar 2010 22:06:51 GMT 123 <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>??? IP</title> </head> <body> <div style='text-align: center; font: 32pt Verdana;margin-top: 300px'> ??? IP  94.103.87.153 </div> </body> </html> 0 Whence these numbers (123 an 0) takes?

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How do I make JavaScript to set these element values?

- by dmanexe

I have two fields that need to multiply each other and fill a 3rd form's value. Here's the HTML: <input type="text" name="estimate[concrete][price]" value="" onBlur="calc_concreteprice(document.forms.mainform);" /> per SF <strong>times</strong> <input type="text" name="estimate[concrete][sqft]" value="" onBlur="calc_concreteprice(document.forms.mainform);" /> SF = <input type="text" name="estimate[concrete][quick_total]" value="" /> Here's my JavaScript: function calc_concreteprice(mainform) { var oprice; var ototal; oprice = ((mainform.estimate[concrete][sqft].value) * (mainform.estimate[concrete][price].value)); ototal = (oprice); mainform.estimate[concrete][quick_total].value = ototal; } I want the first two forms to be multiplied together and output to the third. I think my problem may be within how I am referencing the input field names, with brackets (I'm taking results from this form as an array so I'm already used to working with the results as a multi-dimensional array). Thanks for the help!

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Spring.net customer namespace parser

- by ListenToRick

I have a customer parser which looks like this: [NamespaceParser( Namespace = "http://mysite/schema/cache", SchemaLocationAssemblyHint = typeof(CacheNamespaceParser ), SchemaLocation = "/cache.xsd" ) ] public class CacheNamespaceParser : NamespaceParserSupport { public override void Init() { RegisterObjectDefinitionParser("cache", new CacheParser ()); } } public class CacheParser : AbstractSimpleObjectDefinitionParser { protected override Type GetObjectType(XmlElement element) { return typeof(CacheDefinition); } protected override void DoParse(XmlElement element, ObjectDefinitionBuilder builder) { } protected override bool ShouldGenerateIdAsFallback { get { return true; } } } in the web config i have the following configuration.... <spring> <parsers> <parser type="Spring.Data.Config.DatabaseNamespaceParser, Spring.Data"/> <parser type="App.Web.CacheNamespaceParser, WebApp" /> </parsers> When I run the project I get the following error: An error occurred creating the configuration section handler for spring/parsers: Invalid resource name. Name has to be in 'assembly:<assemblyName>/<namespace>/<resourceName>' format. I put a break point in the CacheNamespaceParser init method and it is called. If I remove from the web config all is well! Any ideas whats wrong

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In need of a Smarter Environmental Package Configuration

- by Jeremy Liberman

I am trying to set up a package template in SSIS, following the Wrox Programmer to Programmer book, SQL Server 2008 Integration Services: Problem - Design - Solution. I'm really liking this book even though it is 2008 and we're using SQL Server 2005. I've got a working package template that uses an Indirect XML package configuration to identify what environment (local developer, dev, QA, production, etc) the package is being run in. That locates the SQL Server package configuration for the environment. That set-up is great and all except for the environment variable at the very front of it all. My team would prefer it if the package could use the same environment resource locator as all our other applications and tools use, so we don't two environment markers with essentially the same information in them. Normally we look up a registry key in HKey_Local_Machine but the Registry Package Configuration type only lets you look up the HKey_Current_User registries. My first thought was to write a new Package Configuration Type class that extends the Registry type; after all we'd had such luck writing our own custom log provider. SSIS is super extendable, right? So there doesn't seem to be a way to write your own Package Configuration Types. Is there still some way I can configure my SSIS SQL Server package configuration from a HKLM registry key connection string? If this is not possible, what other workarounds are available? My idea is to write a PowerShell script that will create/modify the Environment Variable that the package will use by fetching the connection string from the registry. This way there's still two markers, but at least then it's automatically maintained and automated. Is this kind of workaround necessary? Thank you for your time.

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Jquery, how to escape quotes

- by Sandro Antonucci

I'm using a simple jquery code that grabs html code form a tag and then puts this content into a form input <td class="name_cat" ><span class="name_cat">It's a "test" </span> (5)</td> jquery gets the content into span.name_catand returns it as It's a "test". So when I print this into an input it becomes <input value="It's a "test"" /> which as you can imagine will only show as It's a , the following double quote will close the value tag. What's the trick here to keep the original string while not showing utf8 code in the input? Jquery code $(".edit_cat").click(function(){ tr = $(this).parents("tr:first"); id_cat = $(this).attr("id"); td_name = tr.find(".name_cat"); span_name = tr.find("span.name_cat").html(); form = '<form action="/admin/controllers/edit_cat.php" method="post" >'+ '<input type="hidden" name="id_cat" value="'+id_cat+'" />'+ '<input type="text" name="name_cat" value="'+span_name+'" />'+ '<input type="submit" value="save" />'+ '</form>'; td_name.html(form); console.log(span_name); } ); I basically need html() not to decode Utf8

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writing javascripts function using jquery

- by tazim

Some template written using jquery is as follows . it is not working . Any suggestions to use jquery efficiently . <html> <head> <script type="text/javascript" src="/jquerycall/"></script> <script type="text/javascript"> $(document).ready(function() { self.setInterval("clock()",1000); $("button").click(function() { clock; }); function clock() { clock(); time=new Date(); var s = "<p>" + time + "</p>"; $(s).appendTo("div"); } }); </script> </head> <body> <form method="post"> <button type="button">Click Me</button> <div id="someid"></div> </form> </body> </html>

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Showing multiple models in a single ListView

- by Veer

I've three models (Contacts, Notes, Reminders). I want to search all these and produce the filtered result in a single listview and depending upon the selection I've to display the corresponding view(UserControl) to its right. I want the right way of implementing the design or atleast alternatives to this method that I've tried. Now I've tried it using a IntegratedViewModel having all the properties from all the three models. public class IntegratedViewModel { ContactModel _contactModel; NoteModel _noteModel; public IntegratedViewModel(ContactModel contactModel) { _contactModel = contactModel; } // similarly for other models also public string DisplayTitle // For displaying in ListView { get; //same as set set { If(_contactModel != null) return _contactModel.Name; If(_noteModel != null) return _noteModel.Title; } } // All other properties from the three models includin the Name/Title properties for displaying them in the corresponding views(UserControl) } Now I set the itemsSource as the List<IntegratedViewModel>. I've to now bind the visibility of the views to some properties in the MainViewModel. I tried setting bool properties like IsContactViewSelected, IsNoteViewSelected using the setter of SelectedEntity property which is bound to the ListView's SelectedItem. public SelectedEntity { //get set { oldvalue = _selectedEntity; _selectedEntity = value; // now i find the Type of model selected using oldvalue.ModelType // where ModelType is a property in the IntegratedViewModel // according to the type, i set one of the above bool properties to false // and do the same for _selectedEntity but set the property to true // so that the view corresponding to the selectedEntityType is visible // and others are collapsed } } Here is the problem: For eg: let us say, I selected an item of type ContactModel, the old selection being NoteModel. I set the property IsNoteModelSelected to false according to the oldvalue, it sets the property and then Raises the propertychanged event and does not go and check the remaining if condition where i check for _selectedEntity which is used to set the IsContactModelSelected to true.

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jQuery hide all table rows which contain a hidden field matching a value

- by Famous Nerd

Though I don't doubt this has been answered I cannot find a great match for my question. I have a table for which I'd like to filter rows based on whether or not they contain a hidden field matching a value. I understand that the technique tends to be "show all rows", "filter the set", "show/hide that filtered set" I have the following jquery but I'm aweful with filter and my filtered set seems to always contain no elements. my table is the usual <table> <tr><td>header></td><td> </tr> <tr> <td>a visible cell</td><td><input type='hidden' id='big-asp.net-id' value='what-im-filtering-on' /> </td> </tr> </table> My goal is to be able to match on tr who's descendent contains a hidden input containing either true or false. this is how I've tried the selector (variations of this) and I'm not even testing for the value yet. function OnFilterChanged(e){ //debugger; var checkedVal = $("#filters input[type='radio']:checked").val(); var allRows = $("#match-grid-container .tabular-data tr"); if(checkedVal=="all"){ allRows.show(); } else if(checkedVal=="matched"){ allRows.show(); allRows.filter(function(){$(this).find("input[type='hidden'][id~='IsAutoMatchHiddenField']")}).hide(); } else if(checkedVal=="unmatched"){ } } Am I way off with the filter? is the $(this) required in the filter so that i can do the descendant searching? Thanks kindly

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Easy ways to investigate unknown Python APIs

- by jedi_coder

When studying a snippet of unknown Python code, I occasionally bump into the varName.methodName() pattern. To figure out what's this, I shall study the code more, find where varName was instantiated, find its type. So if varName proves to be an instance of ClassName class, I would knew that methodName() is a method of ClassName. Sometimes varName == self and methodName() is a method of this class, or a method inherited from some other class, if the current class is subclassing some other classes. Are there quick ways / tools that could take 'methodName' as input, scan over all installed Python modules and show which classes have methodName()? The closest thing related to this I know of is ipython. If I type a class name, then dot ('.') then TAB, it can show the class members. Instead of a class I could use a name of an object (which is an instance of a certain class) and it would work too. As soon as I choose a method name from the provided options, I can type '?' or '??' and get some help if there's a docstring. I wonder if ipython can do some intelligent scanning based only on 'methodName' string. If you know alternatives to ipython that could possibly help with this, please do suggest them.

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ASP .NET: Cannot call Page WebMethod using jQuery

- by John

I created a WebMethod in the code-behind file of my page as such: [System.Web.Services.WebMethod()] public static string Test() { return "TEST"; } I created the following HTML page to test it out: <html> <head> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"/></script> <script type="text/javascript"> function test() { $.ajax({ type: "POST", url: "http://localhost/TestApp/TestPage.aspx/Test", data: "{}", contentType: "application/json; charset=utf-8", dataType: "text", success: function(msg) { alert(msg.d); } }); } </script> </head> <body> <button onclick="test();">Click Me</button> </body> </html> When I click the button, the AJAX fires off, but nothing is returned. When I debug my code, the method Test() doesn't even get called. Any ideas?

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database table design

- by e.b.white

I design the tables as below for the system which looks like a package delivering system For example, after user received the package, postman should record in system, and the state(history table) is "delivered",and operator is this postman, the current state(state table) is of course "delivered" history table: +---------------+--------------------------+ | Field | Desc | +---------------+--------------------------+ | id | PRIMARY KEY | +---------------+--------------------------+ | package_id | package_tacking_id | +---------------+--------------------------+ | state | package_state | +---------------+--------------------------+ | operators | operators | +---------------+--------------------------+ | create_time| create_time | +---------------+--------------------------+ state table: +---------------+--------------------------+ | Field | Desc | +---------------+--------------------------+ | id | PRIMARY KEY | +---------------+--------------------------+ | package_id | package_tacking_id | +---------------+--------------------------+ | state | latest_package_state | +---------------+--------------------------+ Above is just the basic information to record, some other information( like invoice, destination,...) should be recored as well. But there are different service types like s1 and s2, for s1 it is not needed to record invoice but s1 need, and maybe s1 need some other information to record (like the tel of end user). After all, at delivering way stations there are additional information to record, and for different service type the information type is different. My question is: 1. For different service type, shall I need to declare different tables(option A) or just one big table which can record all information for all types(option B)? 2. If option A, since the basic information above is MUST, how can prevent from declaring there duplicate fields in different tables?

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SELECT product from subclass: How many queries do I need?

- by Stefano

I am building a database similar to the one described here where I have products of different type, each type with its own attributes. I report a short version for convenience product_type ============ product_type_id INT product_type_name VARCHAR product ======= product_id INT product_name VARCHAR product_type_id INT -> Foreign key to product_type.product_type_id ... (common attributes to all product) magazine ======== magazine_id INT title VARCHAR product_id INT -> Foreign key to product.product_id ... (magazine-specific attributes) web_site ======== web_site_id INT name VARCHAR product_id INT -> Foreign key to product.product_id ... (web-site specific attributes) This way I do not need to make a huge table with a column for each attribute of different product types (most of which will then be NULL) How do I SELECT a product by product.product_id and see all its attributes? Do I have to make a query first to know what type of product I am dealing with and then, through some logic, make another query to JOIN the right tables? Or is there a way to join everything together? (if, when I retrieve the information about a product_id there are a lot of NULL, it would be fine at this point). Thank you

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When to use reinterpret_cast?

- by HeretoLearn

I am little confused with the applicability of reinterpret_cast vs static_cast. From what I have read the general rules are to use static cast when the types can be interpreted at compile time hence the word static. This is the cast the C++ compiler uses internally for implicit casts also. reinterpret_cast are applicable in two scenarios, convert integer types to pointer types and vice versa or to convert one pointer type to another. The general idea I get is this is unportable and should be avoided. Where I am a little confused is one usage which I need, I am calling C++ from C and the C code needs to hold on to the C++ object so basically it holds a void*. What cast should be used to convert between the void * and the Class type? I have seen usage of both static_cast and reinterpret_cast? Though from what I have been reading it appears static is better as the cast can happen at compile time? Though it says to use reinterpret_cast to convert from one pointer type to another?

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