Search Results

Search found 3244 results on 130 pages for 'proof of concept'.

Page 105/130 | < Previous Page | 101 102 103 104 105 106 107 108 109 110 111 112  | Next Page >

  • Creating foreach loops using Code Igniter controller and view

    - by Tim
    Hello, This is a situation I have found myself in a few times and I just want clear it up once and for all. Best just to show you what I need to do in some example code. My Controller function my_controller() { $id = $this->uri->segment(3); $this->db->from('cue_sheets'); $this->db->where('id', $id); $data['get_cue_sheets'] = $this->db->get(); $this->db->from('clips'); $this->db->where('sheet_id', ' CUE SHEET ID GOES IN HERE ??? '); $data['get_clips'] = $this->db->get(); $this->load->view('show_sheets_and_clips', $data); } My View <?php if($get_cue_sheets->result_array()) { ?> <?php foreach($get_cue_sheets->result_array() as $sheetRow): ?> <h1><?php echo $sheetRow['sheet_name']; ?></h1> <br/> <?php if($get_clips->result_array()) { ?> <ul> <?php foreach($get_clips->result_array() as $clipRow): ?> <li><?php echo $clipRow['clip_name']; ?></li> <?php endforeach; ?> </ul> <?php } else { echo 'No Clips Found'; } ?> <?php endforeach; ?> <?php } ?> The problem I am having is the concept of passing data back to the controller from the view as I am sending the Database Queries off to the view as an array, when I really need to get some more information as to which sheet ID I am looking for to show the relevant clips. I hope this makes sense to someone out there. Thanks, Tim

    Read the article

  • Linear feedback shift register?

    - by Mattia Gobbi
    Lately I bumped repeatedly into the concept of LFSR, that I find quite interesting because of its links with different fields and also fascinating in itself. It took me some effort to understand, the final help was this really good page, much better than the (at first) cryptic wikipedia entry. So I wanted to write some small code for a program that worked like a LFSR. To be more precise, that somehow showed how a LFSR works. Here's the cleanest thing I could come up with after some lenghtier attempts (Python): def lfsr(seed, taps): sr, xor = seed, 0 while 1: for t in taps: xor += int(sr[t-1]) if xor%2 == 0.0: xor = 0 else: xor = 1 print xor sr, xor = str(xor) + sr[:-1], 0 print sr if sr == seed: break lfsr('11001001', (8,7,6,1)) #example I named "xor" the output of the XOR function, not very correct. However, this is just meant to show how it circles through its possible states, in fact you noticed the register is represented by a string. Not much logical coherence. This can be easily turned into a nice toy you can watch for hours (at least I could :-) def lfsr(seed, taps): import time sr, xor = seed, 0 while 1: for t in taps: xor += int(sr[t-1]) if xor%2 == 0.0: xor = 0 else: xor = 1 print xor print time.sleep(0.75) sr, xor = str(xor) + sr[:-1], 0 print sr print time.sleep(0.75) Then it struck me, what use is this in writing software? I heard it can generate random numbers; is it true? how? So, it would be nice if someone could: explain how to use such a device in software development come up with some code, to support the point above or just like mine to show different ways to do it, in any language Also, as theres not much didactic stuff around about this piece of logic and digital circuitry, it would be nice if this could be a place for noobies (like me) to get a better understanding of this thing, or better, to understand what it is and how it can be useful when writing software. Should have made it a community wiki? That said, if someone feels like golfing... you're welcome.

    Read the article

  • Help needed in grokking password hashes and salts

    - by javafueled
    I've read a number of SO questions on this topic, but grokking the applied practice of storing a salted hash of a password eludes me. Let's start with some ground rules: a password, "foobar12" (we are not discussing the strength of the password). a language, Java 1.6 for this discussion a database, postgreSQL, MySQL, SQL Server, Oracle Several options are available to storing the password, but I want to think about one (1): Store the password hashed with random salt in the DB, one column Found on SO and elsewhere is the automatic fail of plaintext, MD5/SHA1, and dual-columns. The latter have pros and cons MD5/SHA1 is simple. MessageDigest in Java provides MD5, SHA1 (through SHA512 in modern implementations, certainly 1.6). Additionally, most RDBMSs listed provide methods for MD5 encryption functions on inserts, updates, etc. The problems become evident once one groks "rainbow tables" and MD5 collisions (and I've grokked these concepts). Dual-column solutions rest on the idea that the salt does not need to be secret (grok it). However, a second column introduces a complexity that might not be a luxury if you have a legacy system with one (1) column for the password and the cost of updating the table and the code could be too high. But it is storing the password hashed with a random salt in single DB column that I need to understand better, with practical application. I like this solution for a couple of reasons: a salt is expected and considers legacy boundaries. Here's where I get lost: if the salt is random and hashed with the password, how can the system ever match the password? I have theory on this, and as I type I might be grokking the concept: Given a random salt of 128 bytes and a password of 8 bytes ('foobar12'), it could be programmatically possible to remove the part of the hash that was the salt, by hashing a random 128 byte salt and getting the substring of the original hash that is the hashed password. Then re hashing to match using the hash algorithm...??? So... any takers on helping. :) Am I close?

    Read the article

  • how do i work bool!

    - by user350217
    HI! im a beginner and im really getting frustrated with this whole concept. i dont understand how to exactly use the bool function. i know what it is but i cantfigure out how to make it work in my program. Im trying to say that if my variable "selection" is any letter beween 'A' and 'I' then it is valid and can continue on to the next function which is called calcExchangeAmt(amtExchanged, selection). if it is false i want it to ask the user if they want to repeat the program and if they agree to repeat i want it to clear the screen and restart to the main function. please help edit my work! this is my bool function: bool isSelectionValid(char selection, char yesNo, double amtExchanged) { bool validData; validData = true; if((selection >= 'a' && selection <= 'i') || (selection >= 'A' && selection <= 'I')) { validData = calcExchangeAmt (amtExchanged, selection); } else(validData == false); { cout<<"Do you wish to continue? (Y for Yes / N for No)"; cin>>yesNo; } do { main(); } while ((yesNo =='y')||(yesNo == 'Y')); { system("cls"); } return 0; } this is the warning that im gettng: warning C4800: 'double' : forcing value to bool 'true' or 'false' (performance warning)

    Read the article

  • belongs_to with multiple models

    - by julie p
    Hi there! I am a Rails noob and have a question. I have a feed aggregator that is organized by this general concept: Feed Category (books, electronics, etc) Feed Site Section (home page, books page, etc) Feed (the feed itself) Feed Entry So: class Category < ActiveRecord::Base has_many :feeds has_many :feed_entries, :through => :feeds, :limit => 5 validates_presence_of :name attr_accessible :name, :id end class Section < ActiveRecord::Base has_many :feeds has_many :feed_entries, :through => :feeds, :limit => 5 attr_accessible :name, :id end class Feed < ActiveRecord::Base belongs_to :categories belongs_to :sections has_many :feed_entries validates_presence_of :name, :feed_url attr_accessible :name, :feed_url, :category_id, :section_id end class FeedEntry < ActiveRecord::Base belongs_to :feed belongs_to :category belongs_to :section validates_presence_of :title, :url end Make sense? Now, in my index page, I want to basically say... If you are in the Category Books, on the Home Page Section, give me the feed entries grouped by Feed... In my controller: def index @section = Section.find_by_name("Home Page") @books = Category.find_by_name("Books") end In my view: <%= render :partial => 'feed_list', :locals => {:feed_group => @books.feeds} -%> This partial will spit out the markup for each feed entry in the @books collection of Feeds. Now what I need to do is somehow combine the @books with the @section... I tried this: <%= render :partial => 'feed_list', :locals => {:feed_group => @books.feeds(:section_id => @section.id)} -%> But it isn't limiting by the section ID. I've confirmed the section ID by using the same code in the console... Make sense? Any advice? Thanks!

    Read the article

  • RegularExpression-esque search matching Objects in List

    - by Pindatjuh
    I'm currently working on an implementation of the following idea, and I was wondering if there is any literature on this subject. Working with Java, but the principle applies on any language with a decent type-system, I like to implement: matching Objects from a List using a RegularExpression-esque search: So let's say I have a List containing List<Object> x = new ArrayList<Object>(); x.add(new Object()); x.add("Hello World"); x.add("Second String"); x.add(5); // Integer (auto-boxing) x.add(6); // Integer Then I create a "Regular Expression" (not working with a stream of characters, but working with a stream of Objects), and instead of character-classes, I use type-system properties: [String][Integer] And this would match one sublist: {Match["Second String", 5]}. The expression: [String:length()<15] Will match two sublist (each of length 1) containing a String which instance is passing the expression instance.length() < 5: {Match["Hello World"],Match["Second String"]}. [Object][Object] Matches any pair in the List: {Match[Object,"Hello World"],Match["Second String", 5]}, in a streamed manner (no overlapping matches). Ofcourse, my implementation will have grouping, lookahead/lookbehinds and is hierarchical (i.e. matching n elements from Lists in Lists), etc. The above merely illustrates the concept. Is there a name for this principle, and is there literature available on it?

    Read the article

  • How do I properly implement a property in F#?

    - by Greg D
    Consider my first attempt, a simple type in F# like the following: type Test() = inherit BaseImplementingNotifyPropertyChangedViaOnPropertyChanged() let mutable prop: string = null member this.Prop with public get() = prop and public set value = match value with | _ when value = prop -> () | _ -> let prop = value this.OnPropertyChanged("Prop") Now I test this via C# (this object is being exposed to a C# project, so apparent C# semantics are desirable): [TestMethod] public void TaskMaster_Test() { var target = new FTest(); string propName = null; target.PropertyChanged += (s, a) => propName = a.PropertyName; target.Prop = "newString"; Assert.AreEqual("Prop", propName); Assert.AreEqual("newString", target.Prop); return; } propName is properly assigned, my F# Setter is running, but the second assert is failing because the underlying value of prop isn't changed. This sort of makes sense to me, because if I remove mutable from the prop field, no error is generated (and one should be because I'm trying to mutate the value). I think I must be missing a fundamental concept. What's the correct way to rebind/mutate prop in the Test class so that I can pass my unit test?

    Read the article

  • Bi-directional view model syncing with "live" collections and properties (MVVM)

    - by Schneider
    I am getting my knickers in a twist recently about View Models (VM). Just like this guy I have come to the conclusion that the collections I need to expose on my VM typically contain a different type to the collections exposed on my business objects. Hence there must be a bi-directional mapping or transformation between these two types. (Just to complicate things, on my project this data is "Live" such that as soon as you change a property it gets transmitted to other computers) I can just about cope with that concept, using a framework like Truss, although I suspect there will be a nasty surprise somewhere within. Not only must objects be transformed but a synchronization between these two collections is required. (Just to complicate things I can think of cases where the VM collection might be a subset or union of business object collections, not simply a 1:1 synchronization). I can see how to do a one-way "live" sync, using a replicating ObservableCollection or something like CLINQ. The problem then becomes: What is the best way to create/delete items? Bi-directinal sync does not seem to be on the cards - I have found no such examples, and the only class that supports anything remotely like that is the ListCollectionView. Would bi-directional sync even be a sensible way to add back into the business object collection? All the samples I have seen never seem to tackle anything this "complex". So my question is: How do you solve this? Is there some technique to update the model collections from the VM? What is the best general approach to this?

    Read the article

  • t-sql most efficient row to column? crosstab for xml path, pivot

    - by ajberry
    I am looking for the most performant way to turn rows into columns. I have a requirement to output the contents of the db (not actual schema below, but concept is similar) in both fixed width and delimited formats. The below FOR XML PATH query gives me the result I want, but when dealing with anything other than small amounts of data, can take awhile. select orderid ,REPLACE(( SELECT ' ' + CAST(ProductId as varchar) FROM _details d WHERE d.OrderId = o.OrderId ORDER BY d.OrderId,d.DetailId FOR XML PATH('') ),'&#x20;','') as Products from _orders o I've looked at pivot but most of the examples I have found are aggregating information. I just want to combine the child rows and tack them onto the parent. I should also point out I don't need to deal with the column names either since the output of the child rows will either be a fixed width string or a delimited string. For example, given the following tables: OrderId CustomerId ----------- ----------- 1 1 2 2 3 3 DetailId OrderId ProductId ----------- ----------- ----------- 1 1 100 2 1 158 3 1 234 4 2 125 5 3 101 6 3 105 7 3 212 8 3 250 for an order I need to output: orderid Products ----------- ----------------------- 1 100 158 234 2 125 3 101 105 212 250 or orderid Products ----------- ----------------------- 1 100|158|234 2 125 3 101|105|212|250 Thoughts or suggestions? I am using SQL Server 2k5. Example Setup: create table _orders ( OrderId int identity(1,1) primary key nonclustered ,CustomerId int ) create table _details ( DetailId int identity(1,1) primary key nonclustered ,OrderId int ,ProductId int ) insert into _orders (CustomerId) select 1 union select 2 union select 3 insert into _details (OrderId,ProductId) select 1,100 union select 1,158 union select 1,234 union select 2,125 union select 3,105 union select 3,101 union select 3,212 union select 3,250 using FOR XML PATH: select orderid ,REPLACE(( SELECT ' ' + CAST(ProductId as varchar) FROM _details d WHERE d.OrderId = o.OrderId ORDER BY d.OrderId,d.DetailId FOR XML PATH('') ),'&#x20;','') as Products from _orders o which outputs what I want, however is very slow for large amounts of data. One of the child tables is over 2 million rows, pushing the processing time out to ~ 4 hours. orderid Products ----------- ----------------------- 1 100 158 234 2 125 3 101 105 212 250

    Read the article

  • Using Hidden Markov Model for designing AI mp3 player

    - by Casper Slynge
    Hey guys. Im working on an assignment, where I want to design an AI for a mp3 player. The AI must be trained and designed with the use of a HMM method. The mp3 player shall have the functionality of adapting to its user, by analyzing incoming biological sensor data, and from this data the mp3 player will choose a genre for the next song. Given in the assignment is 14 samples of data: One sample consist of Heart Rate, Respiration, Skin Conductivity, Activity and finally the output genre. Below is the 14 samples of data, just for you to get an impression of what im talking about. Sample HR RSP SC Activity Genre S1 Medium Low High Low Rock S2 High Low Medium High Rock S3 High High Medium Low Classic S4 High Medium Low Medium Classic S5 Medium Medium Low Low Classic S6 Medium Low High High Rock S7 Medium High Medium Low Classic S8 High Medium High Low Rock S9 High High Low Low Classic S10 Medium Medium Medium Low Classic S11 Medium Medium High High Rock S12 Low Medium Medium High Classic S13 Medium High Low Low Classic S14 High Low Medium High Rock My time of work regarding HMM is quite low, so my question to you is if I got the right angle on the assignment. I have three different states for each sensor: Low, Medium, High. Two observations/output symbols: Rock, Classic In my own opinion I see my start probabilities as the weightened factors for either a Low, Medium or High state in the Heart Rate. So the ideal solution for the AI is that it will learn these 14 sets of samples. And when a users sensor input is received, the AI will compare the combination of states for all four sensors, with the already memorized samples. If there exist a matching combination, the AI will choose the genre, and if not it will choose a genre according to the weightened transition probabilities, while simultaniously updating the transition probabilities with the new data. Is this a right approach to take, or am I missing something ? Is there another way to determine the output probability (read about Maximum likelihood estimation by EM, but dont understand the concept)? Best regards, Casper

    Read the article

  • Setting Connection Parameters via ADO for MSSQL

    - by taspeotis
    Is it possible to set a connection parameter on a connection to SQL Server and have that variable persist throughout the life of the connection? The parameter must be usable by subsequent queries. We have some old Access reports that use a handful of VBScript functions in the SQL queries (let's call them GetStartDate and GetEndDate) that return global variables. Our application would set these before invoking the query and then the queries can return information between date ranges specified in our application. We are looking at changing to a ReportViewer control running in local mode, but I don't see any convenient way to use these custom functions in straight T-SQL. I have two concept solutions (not tested yet), but I would like to know if there is a better way. Below is some psuedo code. Set all variables before running Recordset.OpenForward Connection->Execute("SET @GetStartDate = ..."); Connection->Execute("SET @GetEndDate = ..."); // Repeat for all parameters Will these variables persist to later calls of Recordset->OpenForward? Can anything reset the variables aside from another SET/SELECT @variable statement? Create an ADOCommand "factory" that automatically adds parameters to each ADOCommand object I will use to execute SQL // Command has been previously been created ADOParameter *Parameter1 = Command->CreateParameter("GetStartDate"); ADOParameter *Parameter2 = Command->CreateParameter("GetEndDate"); // Set values and attach etc... What I would like to know if there is something like: Connection->SetParameter("GetStartDate", "20090101"); Connection->SetParameter("GetEndDate", 20100101"); And these will persist for the lifetime of the connection, and the SQL can do something like @GetStartDate to access them. This may be exactly solution #1, if the variables persist throughout the lifetime of the connection.

    Read the article

  • PHP: Aggregate Model Classes or Uber Model Classes?

    - by sunwukung
    In many of the discussions regarding the M in MVC, (sidestepping ORM controversies for a moment), I commonly see Model classes described as object representations of table data (be that an Active Record, Table Gateway, Row Gateway or Domain Model/Mapper). Martin Fowler warns against the development of an anemic domain model, i.e. a class that is nothing more than a wrapper for CRUD functionality. I've been working on an MVC application for a couple of months now. The DBAL in the application I'm working on started out simple (on account of my understanding - oh the benefits of hindsight), and is organised so that Controllers invoke Business Logic classes, that in turn access the database via DAO/Transaction Scripts pertinent to the task at hand. There are a few "Entity" classes that aggregate these DAO objects to provide a convenient CRUD wrapper, but also embody some of the "behaviour" of that Domain concept (for example, a user - since it's easy to isolate). Taking a look at some of the code, and thinking along refactoring some of the code into a Rich Domain Model, it occurred to me that were I to try and wrap the CRUD routines and behaviour of say, a Company into a single "Model" class, that would be a sizeable class. So, my question is this: do Models represent domain objects, business logic, service layers, all of the above combined? How do you go about defining the responsibilities for these components?

    Read the article

  • Pros/cons of reading connection string from physical file vs Application object (ASP.NET)?

    - by HaterTot
    my ASP.NET application reads an xml file to determine which environment it's currently in (e.g. local, development, production). It checks this file every single time it opens a connection to the database, in order to know which connection string to grab from the Application Settings. I'm entering a phase of development where efficiency is becoming a concern. I don't think it's a good idea to have to read a file on a physical disk ever single time I wish to access the database (very often). I was considering storing the connection string in Application["ConnectionString"]. So the code would be public static string GetConnectionString { if (Application["ConnectionString"] == null) { XmlDocument doc = new XmlDocument(); doc.Load(HttpContext.Current.Request.PhysicalApplicationPath + "bin/ServerEnvironment.xml"); XmlElement xe = (XmlElement) xnl[0]; switch (xe.InnerText.ToString().ToLower()) { case "local": connString = Settings.Default.ConnectionStringLocal; break; case "development": connString = Settings.Default.ConnectionStringDevelopment; break; case "production": connString = Settings.Default.ConnectionStringProduction; break; default: throw new Exception("no connection string defined"); } Application["ConnectionString"] = connString; } return Application["ConnectionString"].ToString(); } I didn't design the application so I figure there must have been a reason for reading the xml file every time (to change settings while the application runs?) I have very little concept of the inner workings here. What are the pros and cons? Do you think I'd see a small performance gain by implementing the function above? THANKS

    Read the article

  • database schema eligible for delta synchronization

    - by WilliamLou
    it's a question for discussion only. Right now, I need to re-design a mysql database table. Basically, this table contains all the contract records I synchronized from another database. The contract record can be modified, deleted or users can add new contract records via GUI interface. At this stage, the table structure is exactly the same as the Contract info (column: serial number, expiry date etc.). In that case, I can only synchronize the whole table (delete all old records, replace with new ones). If I want to delta(only synchronize with modified, new, deleted records) synchronize the table, how should I change the database schema? here is the method I come up with, but I need your suggestions because I think it's a common scenario in database applications. 1)introduce a sequence number concept/column: for each sequence, mark the new added records, modified records, deleted records with this sequence number. By recording the last synchronized sequence number, only pass those records with higher sequence number; 2) because deleted contracts can be added back, and the original table has primary key constraints, should I create another table for those deleted records? or add a flag column to indicate if this contract has been deleted? I hope I explain my question clearly. Anyway, if you know any articles or your own suggestions about this, please let me know. Thanks!

    Read the article

  • Webcrawler, feedback?

    - by Jan Kuboschek
    Hey folks, every once in a while I have the need to automate data collection tasks from websites. Sometimes I need a bunch of URLs from a directory, sometimes I need an XML sitemap (yes, I know there is lots of software for that and online services). Anyways, as follow up to my previous question I've written a little webcrawler that can visit websites. Basic crawler class to easily and quickly interact with one website. Override "doAction(String URL, String content)" to process the content further (e.g. store it, parse it). Concept allows for multi-threading of crawlers. All class instances share processed and queued lists of links. Instead of keeping track of processed links and queued links within the object, a JDBC connection could be established to store links in a database. Currently limited to one website at a time, however, could be expanded upon by adding an externalLinks stack and adding to it as appropriate. JCrawler is intended to be used to quickly generate XML sitemaps or parse websites for your desired information. It's lightweight. Is this a good/decent way to write the crawler, provided the limitations above? http://pastebin.com/VtgC4qVE - Main.java http://pastebin.com/gF4sLHEW - JCrawler.java http://pastebin.com/VJ1grArt - HTMLUtils.java Thanks for your feedback in advance! :)

    Read the article

  • Best ways to copyright protect your work for example Myows

    - by Saif Bechan
    Recently I have read about Myows, they say its: "The universal copyright management and protection app for smart creatives" It is used to protect your application from copyrights and more. Do you think this will be a good idea for large application, or are there better ways to achieve such a thing. url: Myows Update Referencing: http://stackoverflow.com/questions/2618015/has-anyone-tried-myows-to-copyright-protect-your-work/2618628#2618628 Wow there is no better person to have answered this question like the creator himself. Currently I am working on a large web application which is in late testing phase. Because of the complexity of the app there are not many versions of it online so copyright will be a huge issue for me as much of the code is in JavaScript and is easy copyable. I was glad to see that there is some company out there that provide such services, and naturally I wanted to know if there were people using it. I did not know that this type of concept was so 'new'. There were some nice points made in the answer, and I think it will be a good service for people like me. In the next couple of weeks I will be looking further into the subject and start uploading my code and see how it will works out. I will leave this question up because I do want some more suggestions on this topic.

    Read the article

  • Combining aggregate functions in an (ANSI) SQL statement

    - by morpheous
    I have aggregate functions foo(), foobar(), fredstats(), barneystats() I want to create a domain specific query language (DSQL) above my DB, to facilitate using using a domain language to query the DB. The 'language' comprises of boolean expressions (or more specifically SQL like criteria) which I then 'translate' back into pure (ANSI) SQL and send to the underlying Db. The following lines are examples of what the language statements will look like, and hopefully, it will help further clarify the concept: **Example 1** DQL statement: foobar('yellow') between 1 and 3 and fredstats('weight') > 42 Translation: fetch all rows in an underlying table where computed values for aggregate function foobar() is between 1 and 3 AND computed value for AGG FUNC fredstats() is greater than 42 **Example 2** DQL statement: fredstats('weight') < barneystats('weight') AND foo('fighter') in (9,10,11) AND foobar('green') <> 42 Translation: Fetch all rows where the specified criteria matches **Example 3** DQL statement: foobar('green') / foobar('red') <> 42 Translation: Fetch all rows where the specified criteria matches **Example 4** DQL statement: foobar('green') - foobar('red') >= 42 Translation: Fetch all rows where the specified criteria matches Given the following information: The table upon which the queries above are being executed is called 'tbl' table 'tbl' has the following structure (id int, name varchar(32), weight float) The result set returns only the tbl.id, tbl.name and the names of the aggregate functions as columns in the result set - so for example the foobar() AGG FUNC column will be called foobar in the result set. So for example, the first DQL query will return a result set with the following columns: id, name, foobar, fredstats Given the above, my questions then are: What would be the underlying SQL required for Example1 ? What would be the underlying SQL required for Example3 ? Given an algebraic equation comprising of AGGREGATE functions, Is there a way of generalizing the algorithm needed to generate the required ANSI SQL statement(s)? I am using PostgreSQL as the db, but I would prefer to use ANSI SQL wherever possible.

    Read the article

  • Partial Classes - are they bad design?

    - by dferraro
    Hello, I'm wondering why the 'partial class' concept even exists in .NET. I'm working on an application and we are reading a (actually very good) book relavant to the development platform we are implementing at work. In the book he provides a large code base /wrapper around the platform API and explains how he developed it as he teaches different topics about the platform development. Anyway, long story short - he uses partial classes, all over the place, as a way to fake multiple inheritence in C# (IMO). Why he didnt just split the classes up into multiple ones and use composition is beyond me. He will have 3 'partial class' files to make up his base class, each w/ 3-500 lines of code... And does this several times in his API. Do you find this justifiable? If it were me, I'd have followed the S.R.P. and created multiple classes to handle different required behaviors, then create a base class that has instances of these classes as members (e.g. composition). Why did MS even put partial class into the framework?? They removed the ability to expand/collapse all code at each scope level in C# (this was allowed in C++) because it was obviously just allowing bad habits - partial class is IMO the same thing. I guess my quetion is: Can you explain to me when there would be a legitimate reason to ever use a partial class? I do not mean this to be a rant / war thread. I'm honeslty looking to learn something here. Thanks

    Read the article

  • How can I work around WinXP using ports 1025-5000 as ephemeral?

    - by Chris Dolan
    If you create a TCP client socket with port 0 instead of a non-zero port, then the operating system chooses any free ephemeral port for you. Most OSes choose ephemeral ports from the IANA dynamic port range of 49152-65535. However in Windows Server 2003 and earlier (including XP) Microsoft used ports 1025-5000 as the ephemeral range, according to their bind() documentation. I run multiple Java services on the same hardware. On rare occasions, this range collides with well-known ports that I use for other services (e.g. port 4160 for Jini discovery). While rare, this has caused real problems. Is there any easy way to tell Windows or Java to use a different port range for client sockets? Microsoft's docs indicate that I can change the high end of that range via the MaxUserPort TcpIP registry setting, but I see no way to change the low end. Update: I've made some progress on this. It looks like Microsoft has a concept of reserved ports that are exceptions to the ephemeral port range. There's a registry setting that lets you change this permanently and apparently there must be an API to do the same thing because there's a data structure that holds high/low values for reserved port ranges, but I can't find the actual function call anywhere... The registry solution may work, but now I'm fixated on this API.

    Read the article

  • Dependency Property ListBox

    - by developer
    Hi All, I want to use a dependency property, so that my label displays values selected in the listbox. This is just to more clearly understand the working of a dependency property. <Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:WPFToolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit" xmlns:local="clr-namespace:WpfApplication1" x:Name="MyWindow" Height="200" Width="300" > <StackPanel> <ListBox x:Name="lbColor" Width="248" Height="56" ItemsSource="{Binding TestColor}"/> <StackPanel> <Label Content="{Binding Path=Test, ElementName=lbColor}" /> </StackPanel> </StackPanel> </Window> Code Behind, namespace WpfApplication1 { /// <summary> /// Interaction logic for Window1.xaml /// </summary> public partial class Window1 : Window { public ObservableCollection<string> TestColor { get; set; } public String Test { get { return (String)GetValue(TestProperty); } set { SetValue(TestProperty, value); } } // Using a DependencyProperty as the backing store for Title. This enables animation, styling, binding, etc... public static readonly DependencyProperty TestProperty = DependencyProperty.Register("Test", typeof(String), typeof(ListBox), new UIPropertyMetadata("Test1")); public Window1() { InitializeComponent(); TestColor = new ObservableCollection<string>(); DataContext = this; TestColor.Add("Red"); TestColor.Add("Orange"); TestColor.Add("Yellow"); TestColor.Add("Green"); TestColor.Add("Blue"); } } } Can anyone explain me how will I accompalish this using a dependency property. Somehow I am very confused with the Dependency Property concept, and I just wanted to see a working example for that.

    Read the article

  • How would you go about parsing markdown?

    - by John Leidegren
    You can find the syntax here. The thing is, the source that follows with the download is written in perl. Which I have no intentions of honoring. It is riddled with regex and it relies on MD5 hashes to escape certain characters. Something is just wrong about that! I'm about to hard code a parser for markdown and I'm wonder if someone had some experience with this? Edit: If you don't have anything meaningful to say about the actual parsing of markdown, spare me the time. (This might sound harsh, but yes, I'm looking for insight, not a solution i.e. third-party library). To help a bit with the answers, regex are meant to identify patterns! NOT to parse an entire grammar. That people consider doing so is foobar. If you think about markdown, it's fundamentally based around the concept of paragraphs. As such, a reasonable approach might be to split the input into paragraphs. There are many kinds of paragraphs e.g. heading, text, list, blockquote, code. The challenge is thus to identify these paragraphs and in what context they occur. I'll be back with a solution, once I find it's worthy to be shared.

    Read the article

  • Setting Connection Parameters via ADO for SQL Server

    - by taspeotis
    Is it possible to set a connection parameter on a connection to SQL Server and have that variable persist throughout the life of the connection? The parameter must be usable by subsequent queries. We have some old Access reports that use a handful of VBScript functions in the SQL queries (let's call them GetStartDate and GetEndDate) that return global variables. Our application would set these before invoking the query and then the queries can return information between date ranges specified in our application. We are looking at changing to a ReportViewer control running in local mode, but I don't see any convenient way to use these custom functions in straight T-SQL. I have two concept solutions (not tested yet), but I would like to know if there is a better way. Below is some pseudo code. Set all variables before running Recordset.OpenForward Connection->Execute("SET @GetStartDate = ..."); Connection->Execute("SET @GetEndDate = ..."); // Repeat for all parameters Will these variables persist to later calls of Recordset->OpenForward? Can anything reset the variables aside from another SET/SELECT @variable statement? Create an ADOCommand "factory" that automatically adds parameters to each ADOCommand object I will use to execute SQL // Command has been previously been created ADOParameter *Parameter1 = Command->CreateParameter("GetStartDate"); ADOParameter *Parameter2 = Command->CreateParameter("GetEndDate"); // Set values and attach etc... What I would like to know if there is something like: Connection->SetParameter("GetStartDate", "20090101"); Connection->SetParameter("GetEndDate", 20100101"); And these will persist for the lifetime of the connection, and the SQL can do something like @GetStartDate to access them. This may be exactly solution #1, if the variables persist throughout the lifetime of the connection.

    Read the article

  • Value objects in DDD - Why immutable?

    - by Hobbes
    I don't get why value objects in DDD should be immutable, nor do I see how this is easily done. (I'm focusing on C# and Entity Framework, if that matters.) For example, let's consider the classic Address value object. If you needed to change "123 Main St" to "123 Main Street", why should I need to construct a whole new object instead of saying myCustomer.Address.AddressLine1 = "123 Main Street"? (Even if Entity Framework supported structs, this would still be a problem, wouldn't it?) I understand (I think) the idea that value objects don't have an identity and are part of a domain object, but can someone explain why immutability is a Good Thing? EDIT: My final question here really should be "Can someone explain why immutability is a Good Thing as applied to Value Objects?" Sorry for the confusion! EDIT: To clairfy, I am not asking about CLR value types (vs reference types). I'm asking about the higher level DDD concept of Value Objects. For example, here is a hack-ish way to implement immutable value types for Entity Framework: http://rogeralsing.com/2009/05/21/entity-framework-4-immutable-value-objects. Basically, he just makes all setters private. Why go through the trouble of doing this?

    Read the article

  • How can I create a new Person object correctly in Javascript?

    - by TimDog
    I'm still struggling with this concept. I have two different Person objects, very simply: ;Person1 = (function() { function P (fname, lname) { P.FirstName = fname; P.LastName = lname; return P; } P.FirstName = ''; P.LastName = ''; var prName = 'private'; P.showPrivate = function() { alert(prName); }; return P; })(); ;Person2 = (function() { var prName = 'private'; this.FirstName = ''; this.LastName = ''; this.showPrivate = function() { alert(prName); }; return function(fname, lname) { this.FirstName = fname; this.LastName = lname; } })(); And let's say I invoke them like this: var s = new Array(); //Person1 s.push(new Person1("sal", "smith")); s.push(new Person1("bill", "wonk")); alert(s[0].FirstName); alert(s[1].FirstName); s[1].showPrivate(); //Person2 s.push(new Person2("sal", "smith")); s.push(new Person2("bill", "wonk")); alert(s[2].FirstName); alert(s[3].FirstName); s[3].showPrivate(); The Person1 set alerts "bill" twice, then alerts "private" once -- so it recognizes the showPrivate function, but the local FirstName variable gets overwritten. The second Person2 set alerts "sal", then "bill", but it fails when the showPrivate function is called. The new keyword here works as I'd expect, but showPrivate (which I thought was a publicly exposed function within the closure) is apparently not public. I want to get my object to have distinct copies of all local variables and also expose public methods -- I've been studying closures quite a bit, but I'm still confused on this one. Thanks for your help.

    Read the article

  • howto distinguish composition and self-typing use-cases

    - by ayvango
    Scala has two instruments for expressing object composition: original self-type concept and well known trivial composition. I'm curios what situations I should use which in. There are obvious differences in their applicability. Self-type requires you to use traits. Object composition allows you to change extensions on run-time with var declaration. Leaving technical details behind I can figure two indicators to help with classification of use cases. If some object used as combinator for a complex structure such as tree or just have several similar typed parts (1 car to 4 wheels relation) than it should use composition. There is extreme opposite use case. Lets assume one trait become too big to clearly observe it and it got split. It is quite natural that you should use self-types for this case. That rules are not absolute. You may do extra work to convert code between this techniques. e.g. you may replace 4 wheels composition with self-typing over Product4. You may use Cake[T <: MyType] {part : MyType} instead of Cake { this : MyType => } for cake pattern dependencies. But both cases seem counterintuitive and give you extra work. There are plenty of boundary use cases although. One-to-one relations is very hard to decide with. Is there any simple rule to decide what kind of technique is preferable? self-type makes you classes abstract, composition makes your code verbose. self-type gives your problems with blending namespaces and also gives you extra typing for free (you got not just a cocktail of two elements but gasoline-motor oil cocktail known as a petrol bomb). How can I choose between them? What hints are there? Update: Let us discuss the following example: Adapter pattern. What benefits it has with both selt-typing and composition approaches?

    Read the article

< Previous Page | 101 102 103 104 105 106 107 108 109 110 111 112  | Next Page >