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  • A question of style/readability regarding the C# "using" statement

    - by Charles
    I'd like to know your opinion on a matter of coding style that I'm on the fence about. I realize there probably isn't a definitive answer, but I'd like to see if there is a strong preference in one direction or the other. I'm going through a solution adding using statements in quite a few places. Often I will come across something like so: { log = new log(); log.SomeProperty = something; // several of these log.Connection = new OracleConnection("..."); log.InsertData(); // this is where log.Connection will be used ... // do other stuff with log, but connection won't be used again } where log.Connection is an OracleConnection, which implements IDisposable. The neatnik in me wants to change it to: { log = new log(); using (OracleConnection connection = new OracleConnection("...")) { log.SomeProperty = something; log.Connection = conn; log.InsertData(); ... } } But the lover of brevity and getting-the-job-done-slightly-faster wants to do: { log = new log(); log.SomeProperty = something; using (log.Connection = new OracleConnection("...")) log.InsertData(); ... } For some reason I feel a bit dirty doing this. Do you consider this bad or not? If you think this is bad, why? If it's good, why?

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  • Is there a Python module for handling Python object addresses?

    - by cool-RR
    (When I say "object address", I mean the string that you type in Python to access an object. For example 'life.State.step'. Most of the time, all the objects before the last dot will be packages/modules, but in some cases they can be classes or other objects.) In my Python project I often have the need to play around with object addresses. Some tasks that I have to do: Given an object, get its address. Given an address, get the object, importing any needed modules on the way. Shorten an object's address by getting rid of redundant intermediate modules. (For example, 'life.life.State.step' may be the official address of an object, but if 'life.State.step' points at the same object, I'd want to use it instead because it's shorter.) Shorten an object's address by "rooting" a specified module. (For example, 'garlicsim_lib.simpacks.prisoner.prisoner.State.step' may be the official address of an object, but I assume that the user knows where the prisoner package is, so I'd want to use 'prisoner.prisoner.State.step' as the address.) Is there a module/framework that handles things like that? I wrote a few utility modules to do these things, but if someone has already written a more mature module that does this, I'd prefer to use that. One note: Please, don't try to show me a quick implementation of these things. It's more complicated than it seems, there are plenty of gotchas, and any quick-n-dirty code will probably fail for many important cases. These kind of tasks call for battle-tested code. UPDATE: When I say "object", I mostly mean classes, modules, functions, methods, stuff like these. Sorry for not making this clear before.

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  • Practice of checking 'trueness' or 'equality' of conditional statements - does it really make sense?

    - by senthilkumar1033
    I remember many years back, when I was in school, one of my computer science teachers taught us that it was better to check for 'trueness' or 'equality' of a condition and not the negative stuff like 'inequality'. Let me elaborate - If a piece of conditional code can be written by checking whether an expression is true or false, we should check the 'trueness'. Example: Finding out whether a number is odd - it can be done in two ways: if ( num % 2 != 0 ) { // Number is odd } or if ( num % 2 == 1 ) { // Number is odd } When I was beginning to code, I knew that num % 2 == 0 implies the number is even, so I just put a ! there to check if it is odd. But he was like 'Don't check NOT conditions. Have the practice of checking the 'trueness' or 'equality' of conditions whenever possible.' And he recommended that I use the second piece of code. I am not for or against either but I just wanted to know - what difference does it make? Please don't reply 'Technically the output will be the same' - we ALL know that. Is it a general programming practice or is it his own programming practice that he is preaching to others?

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  • SQL Server 2005: Internal Query Processor Error:

    - by Geetha
    I am trying to execute this following procedure in SQL Server 2005. I was able to execute this in my development server and when i tried to use this in the Live Server I am getting an Error "Internal Query Processor Error: The query processor could not produce a query plan. For more information, contact Customer Support Services". am using the same Database and the same format. when we searched in the web it shows some fixes to be used in sql server 2005 to avoid this error but my DBA has confirmed that all the patches are updated in our server. can anyone give me some clue on this. Query: create Procedure [dbo].[sample_Select] @ID as varchar(40) as Declare @Execstring as varchar(1000) set @Execstring = ' Declare @MID as varchar(40) Set @MID = '''+@ID+''' select * from ( select t1.field1, t1.field2 AS field2 , t1.field3 AS field3 , L.field1 AS field1 , L. field2 AS field2 from table1 AS t1 INNER JOIN MasterTable AS L ON L. field1 = t1. field2 where t1. field2 LIKE @MID ) as DataTable PIVOT ( Count(field2) FOR field3 IN (' Select @Execstring=@Execstring+ L.field2 +',' FROM MasterTable AS L inner join table1 AS t1 ON t1.field1= L.field2 Where t1.field2 LIKE @ID set @Execstring = stuff(@Execstring, len(@Execstring), 1, '') set @Execstring =@Execstring +')) as pivotTable' exec (@Execstring)

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  • Problem with Java FX Look and Feel

    - by drachenfels
    Hi, I was looking at some of the examples from the Deitel and Deitel's book for Programming in Java, and one of the first examples is a very simple Swing display. Hence this snippet of code : import javax.swing.*; public class cdea { public static void main(String args[]){ JOptionPane.showMessageDialog(null,"\"Welcome to Java Programming!\""); System.exit(0); //end method main } } I read some stuff regarding how one can get native UI look and feel by using UIManager.setLookAndFeel( UIManager.getSystemLookAndFeelClassName()); to the program. However, when I just add this to my main method, it gives me a host of errors. Specifically : Multiple markers at this line - Unhandled exception type IllegalAccessException - Unhandled exception type InstantiationException - Unhandled exception type ClassNotFoundException - Unhandled exception type UnsupportedLookAndFeelException However when I use it as part of a try/catch exception loop (is that what it is called?) as detailed on http://stackoverflow.com/questions/1590863/getting-java-applications-to-look-native-on-windows-how , I get the program running properly. Could anyone tell me in simple language why this is so? As in, why can't I directly get the System look and feel; why do I have to use it with exception handling? I'm new to Java, and OOP in general, so I'm sorry if I'm being too simplistic.

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  • Ruby on Rails or PHP... Somehow uncertain

    - by Clamm
    Hi everybody... I've been thinking about this a long time now but i wanna hear your opinion because i always received the ebst answers here. So in advance... thank you guys. Right now i have to make this decision: Shift a prototype webservice to production quality. Choose either Ruby or PHP... (Background: A friend of mine is joining the project and prefers rails) I've already played around a bit with RoR (only basic stuff) but i am really disappointed about the documentation of Rails and Ruby. In relation to PHP i find only fragments or hard to use references. At the end i am a bit scared. I dont wanna waste my time realizing that i am not capable of doing s.th in Ruby what i could with PHP. Maybe only because i am too stupid and don't find a proper explanation ;-) Did anyone experience this shift and can tell me how easy/hard it was to switch from PHP to Ruby? E.G. would you recommend programming it in PHP and using MVC as a base pattern? Thanks for your opinion!!!

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  • Should I really use a UITableView in this situation?

    - by mystify
    Imagine you have a view like this: At the top, there is an UISegmentedControl with two segments. It functions like a tab. Pressing one segment will activate this particular content below that UISegmentedControl. Below the UISegmentedControl are some switches. These modify the way how the content should be rendered. And finally, below those switches, there's a table. Imagine a table not in sense of UITableView, but just what it really is: A table. It shows little messages like twitter messages or chat messages for example, one below the other. Like you know it from skype and other chats. Basically they're just rows with some formatting. A label, some image views, some lines, a background. Pretty basic. The data comes from an array. No core data. The whole thing including the segmented control and setup switches must be scrollable. So what I did is: I put all this stuff in an UIScrollView. Now I have to make the decision if I would use a UITableView inside there for that table part, or if I would just print a lot of rows on to the scroll view (with -drawRect:). But some problems stick in my head: Can I put a UITableView inside a UIScrollView? I assume this makes a lot of problems. I don't want that the table part is separately scrollable. Again imagine that view: First there are some basic choice things (segmented control, switches). Then there comes the table. When you scroll, the whole thing scrolls. That's mainly because this first part with the settings can be pretty big, so you would want to scroll it away. The next thing is: Can I customize UITableView in such a way, that it consists of two parts? One for that settings part, and one for the actual data to display?

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  • c# - sqllite dosnt save data i inserted

    - by samy
    I'm messing around with SQL lite and learning it. I got a table called People, I got some method that connect to the database and do some stuff, like show all the info. Now I'm trying to insert some data and here it get wierd for me. I have this method: private void ExecuteQuery(string txtQuery) { SetConnection(); sql_con.Open(); sql_cmd = sql_con.CreateCommand(); sql_cmd.CommandText = txtQuery; sql_cmd.ExecuteNonQuery(); sql_con.Close(); } and to see all the data I've got this method: private void LoadData() { SetConnection(); sql_con.Open(); sql_cmd = sql_con.CreateCommand(); string CommandText = "SELECT * FROM People"; DB = new SQLiteDataAdapter(CommandText, sql_con); DS.Reset(); DB.Fill(DS); DT = DS.Tables[0]; dataGridView1.DataSource = DT; sql_con.Close(); } When I inset some data and right afther it I call the LoadData(), I can see all the changes I made. After I close the program, and then open it agian and call LoadData(), I don't see the new info that I inserted before. I got some data that I used SQL lite GUI app to insert, and I can see that data every time I call the LoadData() method, but not mine. Do I need to do somthing else to make sure SQL lite saves all the data?

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  • Generating a zend form with dynamic data?

    - by meder
    I need to access my session and based on the session property I need to grab stuff from the database to use as options in my dropdown. $_SESSION is: [sess_name] => Array( [properties] => Array( 1=> Hotel A, 2=> Hotel B ), [selected] => 1 ) I need to grab Hotel A from selected, and then access all accounts under Hotel A from the database: id title hotel_id ------------------------------ 1 Hotel A Twitter Account 1 2 Hotel B Facebook Account 2 3 Hotel A Facebook Account 1 I need ids 1 and 3 because my hotel_id is 1 in the context of: $this->addElement( 'select', 'account', array( 'multioptions' => $NEED_IT_HERE )); Here's my query / session grabbing code: $cs = new Zend_Session_Namespace( SESS_NAME ); $model = new Model_DbTable_Social; $s = " SELECT social_accounts.* FROM social_accounts LEFT JOIN social_media_outlets ON social_media_outlets.id = social_accounts.property WHERE social_accounts.property=".(int)$cs->selectedclient; I have this code in my form page, but I need to move it into my model now.

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  • Html, table, img & css - how to get text to wrap correctly?

    - by Michael Pasqualone
    I've got the following code; however it's not given me the desired result - what I am after is as per the image below, what am I doing wrong? <style> table.control_grid tr { text-align: center; width: 200px; } table.control_grid td { width: 120px; height: 48px; } table.control_grid a { text-decoration: none; } table.control_grid img { vertical-align: text-top; } </style> <table class="control_grid"> <tr> <td><img width="48" height="48" src="icon1.gif">My text & stuff, overflow??</td> <td><img width="48" height="48" src="icon1.gif">Icon1</td> <td><img width="48" height="48" src="icon1.gif">Icon2</td> <td></td> <td></td> </tr> </table> Desired result:

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  • OpenType Font Parsing for Pleasure and Profit (anyone understand these damn tables?)

    - by mustISignUp
    So, this is mainly for fun, I'm poking around and trying to find my way inside a few fonts and i have a few questions i'd reeally appreciate some help on if anyone has done this kind of stuff. cmap table The fonts i am testing with contain several cmap subtables of different formats. I can read them, but i don't understand which i should be using. ie. what is the strategy for choosing the most appropriate subtable? Does this even make sense? glyf table This is really making my head hurt. I'm going by what is on here. Looking at the second table on that page.. I've got 'n' endPtsOfContours, 'n' instructions and 'n' flags but it is not clear to me if i have the same number of flags as contours (i know how many contours i have). Then, to make matters worse..(fun!) i have an array of xCoords and an array of yCoords. These arrays seem to be of indeterminate length and may contain data of either BYTE or SHORT but we are not going to tell you which.. Thanks to anyone willing to shed some light.

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  • C#/DataSet: Create and bind a custom column/property in a DataSet`s DataTable in the XXXDataSet.cs

    - by msfanboy
    Hello, I have a DataSet with a DataTable having the columns Number and Description. I do not want to bind both properties to a BindingSource bound again to 2 controls. What I want is a 3rd column in the DataTable called NumberDescription which is a composition of Number and Description. This property is bound only to 1 control/BindingSource`s property not 2. There is the partial XXXDataSet.Designer.cs file and the partial XXXDataSet.cs file. Of course I have defined the public string NumberDescription {get (doing some checks here;set (doing also some checks here} in the XXXDataSet.cs file. But all this does not bind my new property/Column to the BindingSource the DataTable is bound to because the DataSet does not know the new column/property. To make this new property/column known I could add a new column to the DataTAble in the DataSet designer view naming it NumberDescription. At least I see know the new property in the listing of the BindingSource so I can choose it. But all that did not help?? So how do I do that stuff properly? Should I call the NumberDescription Property in the Number AND Description Property ?

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  • actionscript find and convert text to url

    - by gravesit
    I have this script that grabs a twitter feed and displays in a little widget. What I want to do is look at the text for a url and convert that url to a link. public class Main extends MovieClip { private var twitterXML:XML; // This holds the xml data public function Main() { // This is Untold Entertainment's Twitter id. Did you grab yours? var myTwitterID= "username"; // Fire the loadTwitterXML method, passing it the url to your Twitter info: loadTwitterXML("http://twitter.com/statuses/user_timeline/" + myTwitterID + ".xml"); } private function loadTwitterXML(URL:String):void { var urlLoader:URLLoader = new URLLoader(); // When all the junk has been pulled in from the url, we'll fire finishedLoadingXML: urlLoader.addEventListener(Event.COMPLETE, finishLoadingXML); urlLoader.load(new URLRequest(URL)); } private function finishLoadingXML(e:Event = null):void { // All the junk has been pulled in from the xml! Hooray! // Remove the eventListener as a bit of housecleaning: e.target.removeEventListener(Event.COMPLETE, finishLoadingXML); // Populate the xml object with the xml data: twitterXML = new XML(e.target.data); showTwitterStatus(); } private function addTextToField(text:String,field:TextField):void{ /*Regular expressions for replacement, g: replace all, i: no lower/upper case difference Finds all strings starting with "http://", followed by any number of characters niether space nor new line.*/ var reg:RegExp=/(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig; //Replaces Note: "$&" stands for the replaced string. text.replace(reg,"<a href=\"$&\">$&</a>"); field.htmlText=text; } private function showTwitterStatus():void { // Uncomment this line if you want to see all the fun stuff Twitter sends you: //trace(twitterXML); // Prep the text field to hold our latest Twitter update: twitter_txt.wordWrap = true; twitter_txt.autoSize = TextFieldAutoSize.LEFT; // Populate the text field with the first element in the status.text nodes: addTextToField(twitterXML.status.text[0], twitter_txt); }

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  • Checking Selected Radio Button after POST

    - by coffeeaddict
    I've been using ASP.NET controls which perform a lot of the manual for you. But I'm going back to the basics, what everyone else does. I'm using standard input tags. So for example if I have a radio button group and I select a button. When the form submits and does a POST back to whatever action="MyPage.aspx" then to grab and check the radio button's value that was selected is it always done like this below? <label><input type="radio" name="rbGroup" value='<%# ((Action)Container.DataItem).ID %>'/><%# ((Action)Container.DataItem).Name %></label> So here I'm appending the ID to the value. And then when it hits the page that my action specifies, I'm checking to see which was selected by trimming off and getting that ID from the value: string selection = Request.Form["rbGroup"]; string dbRecordIdSelected = int.Parse(selection.Substring(1)); so now I can check the id they selected...that is the ID of the db record that gave that selected radio it's name. Is that how you basically always check what radio was selected by checking the name/value pair that comes across for that selected radioButton group name? And then you can append stuff like IDs or whatever you want to grab and parse out to then do additional logic on the server-side once that header reaches the server and your specified page in the action attribute? The above code is not production code, just something to explain what I'm talking about.

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  • How can I pass an array resulting from a Perl method by reference?

    - by arareko
    Some XML::LibXML methods return arrays instead of references to arrays. Instead of doing this: $self->process_items($xml->findnodes('items/item')); I want to do something like: $self->process_items(\$xml->findnodes('items/item')); So that in process_items() I can dereference the original array instead of creating a copy: sub process_items { my ($self, $items) = @_; foreach my $item (@$items) { # do something... } } I can always store the results of findnodes() into an array and then pass the array reference to my own method, but let's say I want to try a reduced version of my code. Is that the correct syntax for passing the method results or should I use something different? Thanks! EDIT: Now suppose I want to change process_items() to process_item() so I can do stuff on a single element of the referenced array inside a loop. Something like: $self->process_item($_) for ([ $xml->findnodes('items/item') ]); This doesn't work as process_item() is executed only once because a single value is passed to the for loop (the reference to the array from findnodes()). What's the proper way of using $_ in this case?

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  • Is this method a good aproach to get SQL values from C#?

    - by MadBoy
    I have this little method that i use to get stuff from SQL. I either call it with varSearch = "" or varSearch = "something". I would like to know if having method written this way is best or would it be better to split it into two methods (by overloading), or maybe i could somehow parametrize whole WHERE clausule? private void sqlPobierzKontrahentDaneKlienta(ListView varListView, string varSearch) { varListView.BeginUpdate(); varListView.Items.Clear(); string preparedCommand; if (varSearch == "") { preparedCommand = @" SELECT t1.[KlienciID], CASE WHEN t2.[PodmiotRodzaj] = 'Firma' THEN t2.[PodmiotFirmaNazwa] ELSE t2.[PodmiotOsobaNazwisko] + ' ' + t2.[PodmiotOsobaImie] END AS 'Nazwa' FROM [BazaZarzadzanie].[dbo].[Klienci] t1 INNER JOIN [BazaZarzadzanie].[dbo].[Podmioty] t2 ON t1.[PodmiotID] = t2.[PodmiotID] ORDER BY t1.[KlienciID]"; } else { preparedCommand = @" SELECT t1.[KlienciID], CASE WHEN t2.[PodmiotRodzaj] = 'Firma' THEN t2.[PodmiotFirmaNazwa] ELSE t2.[PodmiotOsobaNazwisko] + ' ' + t2.[PodmiotOsobaImie] END AS 'Nazwa' FROM [BazaZarzadzanie].[dbo].[Klienci] t1 INNER JOIN [BazaZarzadzanie].[dbo].[Podmioty] t2 ON t1.[PodmiotID] = t2.[PodmiotID] WHERE t2.[PodmiotOsobaNazwisko] LIKE @searchValue OR t2.[PodmiotFirmaNazwa] LIKE @searchValue OR t2.[PodmiotOsobaImie] LIKE @searchValue ORDER BY t1.[KlienciID]"; } using (var varConnection = Locale.sqlConnectOneTime(Locale.sqlDataConnectionDetails)) using (SqlCommand sqlQuery = new SqlCommand(preparedCommand, varConnection)) { sqlQuery.Parameters.AddWithValue("@searchValue", "%" + varSearch + "%"); using (SqlDataReader sqlQueryResult = sqlQuery.ExecuteReader()) if (sqlQueryResult != null) { while (sqlQueryResult.Read()) { string varKontrahenciID = sqlQueryResult["KlienciID"].ToString(); string varKontrahent = sqlQueryResult["Nazwa"].ToString(); ListViewItem item = new ListViewItem(varKontrahenciID, 0); item.SubItems.Add(varKontrahent); varListView.Items.AddRange(new[] {item}); } } } varListView.EndUpdate(); }

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  • What's a good way to organize a large collection of personal scripts using git?

    - by spooky note
    I have a large collection of my personal scripts that I would like to start versioning using Git. I've previously organized my code as follows: ~/code/python/projects/ (for large stuff, each project contained in an individual folder) ~/code/python/scripts/ (single file scripts all contained in this directory) ~/code/python/sandbox/ (my testing area) ~/code/python/docs/ (downloaded documentation) ~/code/java/... (as above) Now i'm going to start versioning my code using git, so that I can have history and backup all my code to a remote server. I know if I were using SVN I would just keep my entire "~/code/" directory in a large repository, but I understand this is not a good way to do things with Git. Most info I've seen online suggests keeping all my project folders in a single place (as in, no separate directories for python or java) with each project containing it's own git repository, and simply having a "snippets" directory containing all single-file scripts/experiments that can be converted into projects at a later date. But I'm not sure how I feel about consolidating all of my code directories into one area. Is there a good way to keep my separate code directories intact, or is it not worth the effort? Maybe I'm just attached to the separate code directories because I've never known anything else... Also (as a side note), I'd like to quickly be able to see a chronological history of all my projects and scripts. So I can see which projects I created most recently. I used to do this by keeping a number at the beginning of all my projects, 002project, 003project. Is there automatic or easy way to do this in git without having to add a number to all of the project names? I'm open to any practical or philosophical code organizing advice you have. Thanks!!!

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  • Is inheritance bad nowadays?

    - by mafutrct
    Personally, I think inheritance is a great tool, that, when applied reasonably, can greatly simplify code. However, I seems to me that many modern tools dislike inheritance. Let's take a simple example: Serialize a class to XML. As soon as inheritance is involved, this can easily turn into a mess. Especially if you're trying to serialize a derived class using the base class serializer. Sure, we can work around that. Something like a KnownType attribute and stuff. Besides being an itch in your code that you have to remember to update every time you add a derived class, that fails, too, if you receive a class from outside your scope that was not known at compile time. (Okay, in some cases you can still work around that, for instance using the NetDataContract serializer in .NET. Surely a certain advancement.) In any case, the basic principle still exists: Serialization and inheritance don't mix well. Considering the huge list of programming strategies that became possible and even common in the past decade, I feel tempted to say that inheritance should be avoided in areas that relate to serialization (in particular remoting and databases). Does that make sense? Or am messing things up? How do you handle inheritance and serialization?

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  • Upgraded Eclipse. Every app force closes

    - by user1309500
    I would be really grateful for some urgent advice:- I was merrily building my apps (using eclipse) for Android platform 2.2. Everything all working lovely and ready to upload to the marketplace. I thought I would try to install Google Play Licensing and in the process, I was told to download the LVL but that was not available in my SDK download list - and I read I had to updrage my SDK and ADT to the latest. So I did, I now have: ADT 17.0.0 along with ANDROID DDMS, hierarchy viewer and Traceview at 17.0.0 with Eclipse IDE 1.4.2 And I also upgraded my SDK Android 2.2 stuff to the latest. Now:- I have no errors in my app workplaces on Eclipse. But now when I run the apps, they build but force close straight away upon loading. This includes the app I was working on (and working perfectly before) and all the other apps I have ever made. Every app now force closes and I dont know what to do. Been up all night and was ready to upload them to the market place... :( Any help!? Thanks! Please!

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  • Which one gives you more advantages: Microsoft or SUN/Oracle certification?

    - by edwin.nathaniel
    Which one gives you more advantages: Microsoft or SUN/Oracle certification? If you don't mind, please relate your answer to your career (dev, sys-admin, dba), industry (finance, general consulting, business apps, software house), and location (where you live, does it influence your decision?) as well. One reason I asked this because I heard that having MCP (in C#, MCSAD or whatever the cert is called these days) could give you extra point from the employer perspective if they're a Microsoft Partner. I don't quite understand why and am also wondering if SUN/Oracle certificate holder have similar edge/benefit. I'm also interested to know if Certification plays role where you live. For example: certification could be a big negative sign in Silicon Valley, but might be helpful if you're in other US/Canada cities or outside USA/Canada. If you are an independent software consultant, do these certification helps you win bids? I totally understand that this question might be subjective and could be "closed". But it doesn't hurt to ask I suppose. I also understand that there are people who dislike/disagree (or have negative perspective on technology certification). While there are people who have the opinion that "these are not the kind of employers you would want to work with", I respect you guys, but sometime a pure software product company might not exist in certain cities in the world. And if certification can help one's career somewhere else, I guess that means more opportunities right? I've had experienced in both platforms: (short) .NET and (not too long) Java (minus Oracle DB stuff), but I think it's about time I have to pick one of them and be good at. Where I live right now might also dictates my career albeit insignificant. Anyhow, this last paragraph is just tiny blurb. Thanks!

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  • Is `super` local variable?

    - by Michael
    // A : Parent @implementation A -(id) init { // change self here then return it } @end A A *a = [[A alloc] init]; a. Just wondering, if self is a local variable or global? If it's local then what is the point of self = [super init] in init? I can successfully define some local variable and use like this, why would I need to assign it to self. -(id) init { id tmp = [super init]; if(tmp != nil) { //do stuff } return tmp; } b. If [super init] returns some other object instance and I have to overwrite self then I will not be able to access A's methods any more, since it will be completely new object? Am I right? c. super and self pointing to the same memory and the major difference between them is method lookup order. Am I right? sorry, don't have Mac to try, learning theory as for now...

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  • I can't seem to figure out type variables mixed with classes.

    - by onmach
    I pretty much understand 3/4 the rest of the language, but every time I dip my feet into using classes in a meaningful way in my code I get permantently entrenched. Why doesn't this extremely simple code work? data Room n = Room n n deriving Show class HasArea a where width :: (Num n) => a -> n instance (Num n) => HasArea (Room n) where width (Room w h) = w So, room width is denoted by ints or maybe floats, I don't want to restrict it at this point. Both the class and the instance restrict the n type to Nums, but it still doesn't like it and I get this error: Couldn't match expected type `n1' against inferred type `n' `n1' is a rigid type variable bound by the type signature for `width' at Dungeon.hs:11:16 `n' is a rigid type variable bound by the instance declaration at Dungeon.hs:13:14 In the expression: w In the definition of `width': width (Room w h) = w In the instance declaration for `HasArea (Room n)' So it tells me the types doesn't match, but it doesn't tell me what types it thinks they are, which would be really helpful. As a side note, is there any easy way to debug an error like this? The only way I know to do it is to randomly change stuff until it works.

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  • MVC3 Custom view engine

    - by eth0
    I have a custom View Engine that derives from WebFormViewEngine. There's a lot of stuff going on in here, mostly caching. I want to be able to use WebFormViewEngine AND RazorViewEngine at the same time, is this possible? Ideally I'd like to do; ViewEngines.Add(new MyViewEngine<WebFormsViewEngine>()); ViewEngines.Add(new MyViewEngine<RazorViewEngine>()); if a .ascx/.aspx/.master file exists then use WebForms, otherwise use Razor is a .cshtml file exists. EDIT: I should of worded my question better. As my custom view engine derives from WebFormViewEngine it obviously uses WebForms, I can't derive from two classes. I can derive from RazorViewEngine but then I'll loose WebForms. I can duplicate my code entirely, derive from RazorViewEngine and edit the views file extensions, etc. but as I said I've got a lot of custom code in my view engine and would be duplicating hundreds of lines. WebFormViewEngine and RazorViewEngine derive from BuildManagerViewEngine which in turn implements IViewEngine. The problem with that is I have to implement methods CreatePartialView() and CreateView() but how would I know what to return (WebForms/Razor?) using generics?

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  • ZF2 namespace and file system

    - by user1918648
    I have standard Application module in ZF2. It's configured by default, I didn't change anything. I just added some stuff: module/ Application/ src/ Application/ Entity/ Product/ **Product.php** Controller/ **IndexController.php** Product.php namespace Application\Entity; class Product { } IndexController.php namespace Application\Controller; use Zend\Mvc\Controller\AbstractActionController; use Zend\View\Model\ViewModel; use Application\Entity\Product; class IndexController extends AbstractActionController { public function indexAction() { $product = new Product(); } } and I get following error: Fatal error: Class 'Application\Entity\Product' not found in \module\Application\src\Application\Controller\IndexController.php on line 20 I use the same namespace, but it doesn't see it. Why? P.S: If I will change Product.php to be the following: namespace Application\Entity\Product; class Product { } then in the IndexController.php the following code will be working: namespace Application\Controller; use Zend\Mvc\Controller\AbstractActionController; use Zend\View\Model\ViewModel; use Application\Entity\Product\Product; class IndexController extends AbstractActionController { public function indexAction() { $product = new Product(); } }

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  • Locking a GDI+ Bitmap in Native C++?

    - by user146780
    I can find many examples on how to do this in managed c++ but none for unmanaged. I want to get all the pixel data as efficiently as possible, but some of the scan0 stuff I would need more info about so I can properly iterate through the pixel data and get each rgba value from it. right now I have this: Bitmap *b = new Bitmap(filename); if(b == NULL) { return 0; } UINT w,h; w = b->GetWidth(); h = b->GetHeight(); Rect *r = new Rect(0,0,w,h); BitmapData *lockdat; b->LockBits(r,ImageLockModeRead,PixelFormatDontCare,lockdat); delete(r); if(w == 0 && h == 0) { return 0; } Color c; std::vector<GLubyte> pdata(w * h * 4,0.0); for (unsigned int i = 0; i < h; i++) { for (unsigned int j = 0; j < w; j++) { b->GetPixel(j,i,&c); pdata[i * 4 * w + j * 4 + 0] = (GLubyte) c.GetR(); pdata[i * 4 * w + j * 4 + 1] = (GLubyte) c.GetG(); pdata[i * 4 * w + j * 4 + 2] = (GLubyte) c.GetB(); pdata[i * 4 * w + j * 4 + 3] = (GLubyte) c.GetA(); } } delete(b); return CreateTexture(pdata,w,h); How do I use lockdat to do the equivalent of getpixel? Thanks

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