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  • C#: Get a list of every value for a given key in a set of dictionaries?

    - by Rosarch
    How can I write this code more cleanly/concisely? /// <summary> /// Creates a set of valid URIs. /// </summary> /// <param name="levelVariantURIDicts">A collection of dictionaries of the form: /// dict["filePath"] == theFilePath </param> /// <returns></returns> private ICollection<string> URIsOfDicts(ICollection<IDictionary<string, string>> levelVariantURIDicts) { ICollection<string> result = new HashSet<string>(); foreach (IDictionary<string, string> dict in levelVariantURIDicts) { result.Add(dict["filePath"]); } return result; }

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  • Concise C# code for gathering several properties with a non-null value into a collection?

    - by stakx
    A fairly basic problem for a change. Given a class such as this: public class X { public T A; public T B; public T C; ... // (other fields, properties, and methods are not of interest here) } I am looking for a concise way to code a method that will return all A, B, C, ... that are not null in an enumerable collection. (Assume that declaring these fields as an array is not an option.) public IEnumerable<T> GetAllNonNullAs(this X x) { // ? } The obvious implementation of this method would be: public IEnumerable<T> GetAllNonNullAs(this X x) { var resultSet = new List<T>(); if (x.A != null) resultSet.Add(x.A); if (x.B != null) resultSet.Add(x.B); if (x.C != null) resultSet.Add(x.C); ... return resultSet; } What's bothering me here in particular is that the code looks verbose and repetitive, and that I don't know the initial List capacity in advance. It's my hope that there is a more clever way, probably something involving the ?? operator? Any ideas?

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  • LINQ: Enhancing Distinct With The SelectorEqualityComparer

    - by Paulo Morgado
    On my last post, I introduced the PredicateEqualityComparer and a Distinct extension method that receives a predicate to internally create a PredicateEqualityComparer to filter elements. Using the predicate, greatly improves readability, conciseness and expressiveness of the queries, but it can be even better. Most of the times, we don’t want to provide a comparison method but just to extract the comaprison key for the elements. So, I developed a SelectorEqualityComparer that takes a method that extracts the key value for each element. Something like this: public class SelectorEqualityComparer<TSource, Tkey> : EqualityComparer<TSource> where Tkey : IEquatable<Tkey> { private Func<TSource, Tkey> selector; public SelectorEqualityComparer(Func<TSource, Tkey> selector) : base() { this.selector = selector; } public override bool Equals(TSource x, TSource y) { Tkey xKey = this.GetKey(x); Tkey yKey = this.GetKey(y); if (xKey != null) { return ((yKey != null) && xKey.Equals(yKey)); } return (yKey == null); } public override int GetHashCode(TSource obj) { Tkey key = this.GetKey(obj); return (key == null) ? 0 : key.GetHashCode(); } public override bool Equals(object obj) { SelectorEqualityComparer<TSource, Tkey> comparer = obj as SelectorEqualityComparer<TSource, Tkey>; return (comparer != null); } public override int GetHashCode() { return base.GetType().Name.GetHashCode(); } private Tkey GetKey(TSource obj) { return (obj == null) ? (Tkey)(object)null : this.selector(obj); } } Now I can write code like this: .Distinct(new SelectorEqualityComparer<Source, Key>(x => x.Field)) And, for improved readability, conciseness and expressiveness and support for anonymous types the corresponding Distinct extension method: public static IEnumerable<TSource> Distinct<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> selector) where TKey : IEquatable<TKey> { return source.Distinct(new SelectorEqualityComparer<TSource, TKey>(selector)); } And the query is now written like this: .Distinct(x => x.Field) For most usages, it’s simpler than using a predicate.

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  • Does functional programming mandate new naming conventions?

    - by Jakob
    I recently started studying functional programming using Haskell and came upon this article on the official Haskell wiki: How to read Haskell. The article claims that short variable names such as x, xs, and f are fitting for Haskell code, because of conciseness and abstraction. In essence, it claims that functional programming is such a distinct paradigm that the naming conventions from other paradigms don't apply. What are your thoughts on this?

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  • Is it bad to explicitly compare against boolean constants e.g. if (b == false) in Java?

    - by polygenelubricants
    Is it bad to write: if (b == false) //... while (b != true) //... Is it always better to instead write: if (!b) //... while (!b) //... Presumably there is no difference in performance (or is there?), but how do you weigh the explicitness, the conciseness, the clarity, the readability, etc between the two? Note: the variable name b is just used as an example, ala foo and bar.

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  • Is it good practice to use the XOR (^) operator in Java for boolean checks?

    - by Pete
    I personally like the 'exclusive or' operator when it makes sense in context of boolean checks because of its conciseness. I much prefer to write if (boolean1 ^ boolean2) { //do it } than if((boolean1 && !boolean2) || (boolean2 && !boolean1)) { //do it } but I often get confused looks (from other experienced java developers, not just the newbies), and sometimes comments about how it should only be used for bitwise operations. I'm curious as to the best practices others use around the '^' operator.

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  • LINQ: Enhancing Distinct With The PredicateEqualityComparer

    - by Paulo Morgado
    Today I was writing a LINQ query and I needed to select distinct values based on a comparison criteria. Fortunately, LINQ’s Distinct method allows an equality comparer to be supplied, but, unfortunately, sometimes, this means having to write custom equality comparer. Because I was going to need more than one equality comparer for this set of tools I was building, I decided to build a generic equality comparer that would just take a custom predicate. Something like this: public class PredicateEqualityComparer<T> : EqualityComparer<T> { private Func<T, T, bool> predicate; public PredicateEqualityComparer(Func<T, T, bool> predicate) : base() { this.predicate = predicate; } public override bool Equals(T x, T y) { if (x != null) { return ((y != null) && this.predicate(x, y)); } if (y != null) { return false; } return true; } public override int GetHashCode(T obj) { if (obj == null) { return 0; } return obj.GetHashCode(); } } Now I can write code like this: .Distinct(new PredicateEqualityComparer<Item>((x, y) => x.Field == y.Field)) But I felt that I’d lost all conciseness and expressiveness of LINQ and it doesn’t support anonymous types. So I came up with another Distinct extension method: public static IEnumerable<TSource> Distinct<TSource>(this IEnumerable<TSource> source, Func<TSource, TSource, bool> predicate) { return source.Distinct(new PredicateEqualityComparer<TSource>(predicate)); } And the query is now written like this: .Distinct((x, y) => x.Field == y.Field) Looks a lot better, doesn’t it?

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  • Future proof Primary Key design in postgresql

    - by John P
    I've always used either auto_generated or Sequences in the past for my primary keys. With the current system I'm working on there is the possibility of having to eventually partition the data which has never been a requirement in the past. Knowing that I may need to partition the data in the future, is there any advantage of using UUIDs for PKs instead of the database's built-in sequences? If so, is there a design pattern that can safely generate relatively short keys (say 6 characters instead of the usual long one e6709870-5cbc-11df-a08a-0800200c9a66)? 36^6 keys per-table is more than sufficient for any table I could imagine. I will be using the keys in URLs so conciseness is important.

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  • What is more interesting or powerful: Curry/Mercury/Lambda-Prolog/your suggestion.

    - by Bubba88
    Hi! I would like to ask you about what formal system could be more interesting to implement from scratch/reverse engineer. I've looked through some existing and rather open (open in the sense of free/open-source) projects of logical/declarative programming systems. I've decided to make up something similar in my free time, or at least to catch the general idea of implementation. It would be great if some of these systems would provide most of the expressive power and conciseness of modern academic investigations in logic and it's relation with computational models. What would you recommend to study at least at the conceptual level? For example, Lambda-Prolog is interesting particularly because it allows for higher order relations, but AFAIK (I might really be mistaken :)) is based on intuitionist logic and therefore lack the excluded-middle principle; that's generally a disatvantage for me.. I would also welcome any suggestions about modern logical programming systems which are less popular but more expressive/powerful. I guess, this question will need refactoring, but thank you in advance! :)

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  • Why doesn't this list comprehension do what I expect it to do?

    - by Az
    The original list project_keys = sorted(projects.keys()) is [101, 102, 103, 104, 105, 106, 107, 108, 109, 110] where the following projects were deemed invalid this year: 108, 109, 110. Thus: for project in projects.itervalues(): # The projects dictionary is mapped to the Project class if project.invalid: # Where invalid is a Bool parameter in the Project class project_keys.remove(project.proj_id) print project_keys This will return a list of integers (which are project id's) as such: [101, 102, 103, 104, 105, 106, 107] Sweet. Now, I wanted it try the same thing using a list comprehension. project_keys = [project_keys.remove(project.proj_id) for project in projects.itervalues() if project.invalid print project_keys This returns: [None, None, None] So I'm populating a list with the same number as the removed elements but they're Nones? Can someone point out what I'm doing wrong? Additionally, why would I use a list comprehension over the for-if block at the top? Conciseness? Looks nicer?

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  • when to use StringBuilder in java

    - by kostja
    It is supposed to be generally preferable to use a StringBuilder for String concatenation in Java. Is it always the case? What i mean is : Is the overhead of creating a StringBuilder object, calling the append() method and finally toString() smaller then concatenating existing Strings with + for 2 Strings already or is it only advisable for more Strings? If there is such a threshold, what does it depend on (the String length i suppose, but in which way)? And finally - would you trade the readability and conciseness of the + concatenation for the performance of the StringBuilder in smaller cases like 2, 3, 4 Strings?

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  • What is the term(s) used to describe programming language syntax?

    - by Mr Roys
    Is there an exact/correct term to describe this difference between the syntax/constructs of programming langauges e.g VB6 with its (if ... else ... endif) and C# with its curly braces for conditional statements. I'm using VB6 syntax and C# as examples since I'm more familiar with their syntax. For example, Visual Basic 6's syntax uses a more verbose, natural language like structure. If (id = 0) Then id = MyObject.Add(Me) Else Call MyObject.Update(Me) End If while C# has more concise syntax like: if (id == 0) { id = MyObject.Add(this); } else { MyObject.Update(this); } Conciseness? Natural languageness? Or is there a more "scientific" word for describing syntax?

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  • Visual Studio 2010 Best Practices

    - by Etienne Tremblay
    I’d like to thank Packt for providing me with a review version of Visual Studio 2010 Best Practices eBook. In fairness I also know the author Peter having seen him speak at DevTeach on many occasions.  I started by looking at the table of content to see what this book was about, knowing that “best practices” is a real misnomer I wanted to see what they were.  I really like the fact that he starts the book by really saying they are not really best practices but actually recommend practices.  As a Team Foundation Server user I found that chapter 2 was more for the open source crowd and I really skimmed it.  The portion on Branching was well documented, although I’m not a fan of the testing branch myself, but the rest was right on. The section on merge remote changes (bring the outside to you) paradigm is really important and was touched on. Chapter 3 has good solid practices on low level constructs like generics and exceptions. Chapter 4 dives into architectural practices like decoupling, distributed architecture and data based architecture.  DTOs and ORMs are touched on briefly as is NoSQL. Chapter 5 is about deployment and is really a great primer on all the “packaging” technologies like Visual Studio Setup and Deployment (depreciated in 2012), Click Once and WIX the major player outside of commercial solutions.  This is a nice section on how to move from VSSD to WIX this is going to be important in the coming years due to the fact that VS 2012 doesn’t support VSSD. In chapter 6 we dive into automated testing practices, including test coverage, mocking, TDD, SpecDD and Continuous Testing.  Peter covers all those concepts really nicely albeit succinctly. Being a book on recommended practices I find this is really good. I really enjoyed chapter 7 that gave me a lot of great tips to enhance my Visual Studio “experience”.  Tips on organizing projects where good.  Also even though I knew about configurations I like that he put that in there so you can move all your settings to another machine, a lot of people don’t know about that. Quick find and Resharper are also briefly covered.  He touches on macros (depreciated in 2012).  Finally he touches on Continuous Integration a very important concept in today’s ALM landscape. Chapter 8 is all about Parallelization, threads, Async, division of labor, reactive extensions.  All those concepts are touched on and again generalized approaches to those modern problems are giving.       Chapter 9 goes into distributed apps, the most used and accepted practice in the industry for .NET projects the chapter tackles concepts like Scalability, Messaging and Cloud (the flavor of the month of distributed apps, although I think this will stick ;-)).  He also looks a protocols TCP/UDP and how to debug distributed apps.  He touches on logging and health monitoring. Chapter 10 tackles recommended practices for web services starting with implementing WCF services, which goes into all sort of goodness like how to host in IIS or self-host.  How to manual test WCF services, also a section on authentication and authorization.  ASP.NET Web services are also touched on in that chapter All in all a good read, nice tips and accepted practices.  I like the conciseness of the subjects and Peter touches on a lot of things in this book and uses a lot of the current technologies flavors to explain the concepts.   Cheers, ET

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  • Call For Papers Tips and Tricks

    - by speakjava
    This year's JavaOne session review has just been completed and by now everyone who submitted papers should know whether they were successful or not.  I had the pleasure again this year of leading the review of the 'JavaFX and Rich User Experiences' track.  I thought it would be useful to write up a few comments to help people in future when submitting session proposals, not just for JavaOne, but for any of the many developer conferences that run around the world throughout the year.  This also draws on conversations I recently had with various Java User Group leaders at the Oracle User Group summit in Riga.  Many of these leaders run some of the biggest and most successful Java conferences in Europe. Try to think of a title which will sound interesting.  For example, "Experiences of performance tuning embedded Java for an ARM architecture based single board computer" probably isn't going to get as much attention as "Do you like coffee with your dessert? Java on the Raspberry Pi".  When thinking of the subject and title for your talk try to steer clear of sessions that might be too generic (and so get lost in a group of similar sessions).  Introductory talks are great when the audience is new to a subject, but beware of providing sessions that are too basic when the technology has been around for a while and there are lots of tutorials already available on the web. JavaOne, like many other conferences has a number of fields that need to be filled in when submitting a paper.  Many of these are selected from pull-down lists (like which track the session is applicable to).  Check these lists carefully.  A number of sessions we had needed to be shuffled between tracks when it was thought that the one selected was not appropriate.  We didn't count this against any sessions, but it's always a good idea to try and get the right one from the start, just in case. JavaOne, again like many other conferences, has two fields that describe the session being submitted: abstract and summary.  These are the most critical to a successful submission.  The two fields have different names and that is significant; a frequent mistake people make is to write an abstract for a session and then duplicate it for the summary.  The abstract (at least in the case of JavaOne) is what gets printed in the show guide and is typically what will be used by attendees when deciding what sessions to attend.  This is where you need to sell your session, not just to the reviewers, but also the people who you want in your audience.  Submitting a one line abstract (unless it's a really good one line) is not usually enough to decide whether this is worth investing an hour of conference time.  The abstract typically has a limit of a few hundred characters.  Try to use as many of them as possible to get as much information about your session across.  The summary should be different from the abstract (and don't leave it blank as some people do).  This field is where you can give the reviewers more detail about things like the structure of the talk, possible demonstrations and so on.  As a reviewer I look to this section to help me decide whether the hard-sell of the title and abstract will actually be reflected in the final content.  Try to make this comprehensive, but don't make it excessively long.  When you have to review possibly hundreds of sessions a certain level of conciseness can make life easier for reviewers and help the cause of your session. If you've not made many submissions for talks in the past, or if this is your first, try to give reviewers places to find background on you as a presenter.  Having an active blog and Twitter handle can also help reviewers if they're not sure what your level of expertise is.  Many call-for-papers have places for you to include this type of information.  It's always good to have new and original presenters and presentations for conferences.  Hopefully these tips will help you be successful when you answer the next call-for-papers.

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  • Updating extra attributes in a has_many, :through relationship using Rails

    - by Robbie
    I've managed to set up a many-to-many relationship between the following models Characters Skills PlayerSkills PlayerSkills, right now, has an attribute that Skills don't normally have: a level. The models look something like this (edited for conciseness): class PlayerSkill < ActiveRecord::Base belongs_to :character belongs_to :skill end class Skill < ActiveRecord::Base has_many :player_skills has_many :characters, :through => :player_skills attr_accessible :name, :description end class Character < ActiveRecord::Base belongs_to :user has_many :player_skills has_many :skills, :through => :player_skills end So nothing too fancy in the models... The controller is also very basic at this point... it's pretty much a stock update action. The form I'm looking to modify is characters#edit. Right now it renders a series of checkboxes which add/remove skills from the characters. This is great, but the whole point of using has_many :through was to track a "level" as well. Here is what I have so far: - form_for @character do |f| = f.error_messages %p = f.label :name %br = f.text_field :name %p = f.label :race %br = f.text_field :race %p = f.label :char_class %br = f.text_field :char_class %p - @skills.each do |skill| = check_box_tag "character[skill_ids][]", skill.id, @character.skills.include?(skill) =h skill.name %br %p = f.submit After it renders "skill.name", I need it to print a text_field that updates player_skill. The problem, of course, is that player_skill may or may not exist! (Depending on if the box was already ticked when you loaded the form!) From everything I've read, has_many :through is great because it allows you to treat the relationship itself as an entity... but I'm completely at a loss as to how to handle the entity in this form. As always, thanks in advance for any and all help you can give me!

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  • How would the 'Model' in a Rails-type webapp be implemented in a functional programming langauge?

    - by ceptorial
    In MVC web development frameworks such as Ruby on Rails, Django, and CakePHP, HTTP requests are routed to controllers, which fetch objects which are usually persisted to a backend database store. These objects represent things like users, blog posts, etc., and often contain logic within their methods for permissions, fetching and/or mutating other objects, validation, etc. These frameworks are all very much object oriented. I've been reading up recently on functional programming and it seems to tout tremendous benefits such as testability, conciseness, modularity, etc. However most of the examples I've seen for functional programming implement trivial functionality like quicksort or the fibonnacci sequence, not complex webapps. I've looked at a few 'functional' web frameworks, and they all seem to implement the view and controller just fine, but largely skip over the whole 'model' and 'persistence' part. (I'm talking more about frameworks like Compojure which are supposed to be purely functional, versus something Lift which conveniently seems to use the OO part of Scala for the model -- but correct me if I'm wrong here.) I haven't seen a good explanation of how functional programming can be used to provide the metaphor that OO programming provides, i.e. tables map to objects, and objects can have methods which provide powerful, encapsulated logic such as permissioning and validation. Also the whole concept of using SQL queries to persist data seems to violate the whole 'side effects' concept. Could someone provide an explanation of how the 'model' layer would be implemented in a functionally programmed web framework?

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  • Pseudo-quicksort time complexity

    - by Ord
    I know that quicksort has O(n log n) average time complexity. A pseudo-quicksort (which is only a quicksort when you look at it from far enough away, with a suitably high level of abstraction) that is often used to demonstrate the conciseness of functional languages is as follows (given in Haskell): quicksort :: Ord a => [a] -> [a] quicksort [] = [] quicksort (p:xs) = quicksort [y | y<-xs, y<p] ++ [p] ++ quicksort [y | y<-xs, y>=p] Okay, so I know this thing has problems. The biggest problem with this is that it does not sort in place, which is normally a big advantage of quicksort. Even if that didn't matter, it would still take longer than a typical quicksort because it has to do two passes of the list when it partitions it, and it does costly append operations to splice it back together afterwards. Further, the choice of the first element as the pivot is not the best choice. But even considering all of that, isn't the average time complexity of this quicksort the same as the standard quicksort? Namely, O(n log n)? Because the appends and the partition still have linear time complexity, even if they are inefficient.

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  • Quickly or concisely determine the longest string per column in a row-based data collection

    - by ccornet
    Judging from the failure of my last inquiry, I need to calculate and preset the widths of a set of columns in a table that is being made into an Excel file. Unfortunately, the string data is stored in a row-based format, but the widths must be calculated in a column-based format. The data for the spreadsheets are generated from the following two collections: var dictFiles = l.Items.Cast<SPListItem>().GroupBy(foo => foo.GetSafeSPValue("Category")).ToDictionary(bar => bar.Key); StringDictionary dictCols = GetColumnsForItem(l.Title); Where l is an SPList whose title determines which columns are used. Each SPListItem corresponds to a row of data, which are sorted into separate worksheets based on Category (hence the dictionary). The second line is just a simple StringDictionary that has the column name (A, B, C, etc.) as a key and the corresponding SPListItme field display name as the corresponding value. So for each Category, I enumerate through dictFiles[somekey] to get all the rows in that sheet, and get the particular cell data using SPListItem.Fields[dictCols[colName]]. What I am asking is, is there a quick or concise method, for any one dictFiles[somekey], to retrieve a readout of the longest string in each column provided by dictCols? If it is impossible to get both quickness and conciseness, I can settle for either (since I always have the O(n*m) route of just enumerating the collection and updating an array whenever strCurrent.Length strLongest.Length). For example, if the goal table was the following... Item# Field1 Field2 Field3 1 Oarfish Atmosphere Pretty 2 Raven Radiation Adorable 3 Sunflower Flowers Cute I'd like a function which could cleanly take the collection of items 1, 2, and 3 and output in the correct order... Sunflower, Atmosphere, Adorable Using .NET 3.5 and C# 3.0.

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  • WPF Converter and NotifyOnTargetUpdated exclusive in a binding ?

    - by Mathieu Garstecki
    Hi, I have a problem with a databinding in WPF. When I try to use a value converter and set the NotifyOnTargetUpdated=True property to True, I get an XamlParseException with the following message: 'System.Windows.Data.BindingExpression' value cannot be assigned to property 'Contenu' of object 'View.UserControls.ShadowedText'. Value cannot be null. Parameter name: textToFormat Error at object 'System.Windows.Data.Binding' in markup file 'View.UserControls;component/saletotal.xaml' Line 363 Position 95. The binding is pretty standard: <my:ShadowedText Contenu="{Binding Path=Total, Converter={StaticResource CurrencyToStringConverter}, NotifyOnTargetUpdated=True}" TargetUpdated="MontantTotal_TargetUpdated"> </my:ShadowedText> (Styling properties removed for conciseness) The converter exists in the resources and works correctly when NotifyOnTargetUpdated=True is removed. Similarly, the TargetUpdated event is called and implemented correctly, and works when the converter is removed. Note: This binding is defined in a ControlTemplate, though I don't think that is relevant to the problem. Can anybody explain me what is happening ? Am I defining the binding wrong ? Are those features mutually exclusive (and in this case, can you explain why it is so) ? Thanks in advance. More info: Here is the content of the TargetUpdated handler: private void MontantTotal_TargetUpdated(object sender, DataTransferEventArgs e) { ShadowedText textBlock = (ShadowedText)e.TargetObject; double textSize = textBlock.Taille; double delta = 5; double defaultTaille = 56; double maxWidth = textBlock.MaxWidth; while (true) { FormattedText newFormat = new FormattedText(textBlock.Contenu, CultureInfo.CurrentCulture, FlowDirection.LeftToRight, new Typeface("Calibri"), textSize, (SolidColorBrush) Resources["RougeVif"]); if (newFormat.Width < textBlock.MaxWidth && textSize <= defaultTaille) { if ((Math.Round(newFormat.Width) + delta) >= maxWidth || textSize == defaultTaille) { break; } textSize++; } else { if ((Math.Round(newFormat.Width) - delta) <= maxWidth && textSize <= defaultTaille) { break; } textSize--; } } textBlock.Taille = textSize; } The role of the handler is to resize the control based on the length of the content. It is quite ugly but I want to have the functional part working before refactoring.

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  • How do I use accepts_nested_attributes_for? I cannot use the .build method (!)

    - by Angela
    Editing my question for conciseness and to update what I've done: How do I model having multiple Addresses for a Company and assign a single Address to a Contact, and be able to assign them when creating or editing a Contact? Here is my model for Contacts: class Contact < ActiveRecord::Base attr_accessible :first_name, :last_name, :title, :phone, :fax, :email, :company, :date_entered, :campaign_id, :company_name, :address_id, :address_attributes belongs_to :company belongs_to :address accepts_nested_attributes_for :address end Here is my model for Address: class Address < ActiveRecord::Base attr_accessible :street1, :street2, :city, :state, :zip has_many :contacts end I would like, when creating an new contact, access all the Addresses that belong to the other Contacts that belong to the Company. So here is how I represent Company: class Company < ActiveRecord::Base attr_accessible :name, :phone, :addresses has_many :contacts has_many :addresses, :through => :contacts end Here is how I am trying to create a field in the View for _form for Contact so that, when someone creates a new Contact, they pass the address to the Address model and associate that address to the Contact: <% f.fields_for :address, @contact.address do |builder| %> <p> <%= builder.label :street1, "Street 1" %> </br> <%= builder.text_field :street1 %> <p> <% end %> When I try to Edit, the field for Street 1 is blank. And I don't know how to display the value from show.html.erb. At the bottom is my error console -- can't seem to create values in the address table: My Contacts controller is as follows: def new @contact = Contact.new @contact.address.build # I GET AN ERROR HERE: says NIL CLASS @contact.date_entered = Date.today @campaigns = Campaign.find(:all, :order => "name") if params[:campaign_id].blank? else @campaign = Campaign.find(params[:campaign_id]) @contact.campaign_id = @campaign.id end if params[:company_id].blank? else @company = Company.find(params[:company_id]) @contact.company_name = @company.name end end def create @contact = Contact.new(params[:contact]) if @contact.save flash[:notice] = "Successfully created contact." redirect_to @contact else render :action => 'new' end end def edit @contact = Contact.find(params[:id]) @campaigns = Campaign.find(:all, :order => "name") end Here is a snippet of my error console: I am POSTING the attribute, but it is not CREATING in the Address table.... Processing ContactsController#create (for 127.0.0.1 at 2010-05-12 21:16:17) [POST] Parameters: {"commit"="Submit", "authenticity_token"="d8/gx0zy0Vgg6ghfcbAYL0YtGjYIUC2b1aG+dDKjuSs=", "contact"={"company_name"="Allyforce", "title"="", "campaign_id"="2", "address_attributes"={"street1"="abc"}, "fax"="", "phone"="", "last_name"="", "date_entered"="2010-05-12", "email"="", "first_name"="abc"}} Company Load (0.0ms)[0m [0mSELECT * FROM "companies" WHERE ("companies"."name" = 'Allyforce') LIMIT 1[0m Address Create (16.0ms)[0m [0;1mINSERT INTO "addresses" ("city", "zip", "created_at", "street1", "updated_at", "street2", "state") VALUES(NULL, NULL, '2010-05-13 04:16:18', NULL, '2010-05-13 04:16:18', NULL, NULL)[0m Contact Create (0.0ms)[0m [0mINSERT INTO "contacts" ("company", "created_at", "title", "updated_at", "campaign_id", "address_id", "last_name", "phone", "fax", "company_id", "date_entered", "first_name", "email") VALUES(NULL, '2010-05-13 04:16:18', '', '2010-05-13 04:16:18', 2, 2, '', '', '', 5, '2010-05-12', 'abc', '')[0m

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  • How do I send an email with embedded images AND regular attachments in JavaMail?

    - by Chris
    Hi, I'd like to know how to build an SMTP multipart message in the correct order so that it will render correctly on the iPhone mail client (rendering correctly in GMail). I'm using Javamail to build up an email containing the following parts: A body part with content type "text/html; UTF-8" An embedded image attachment. A file attachment I am sending the mail via GMail SMTP (via SSL) and the mail is sent and rendered correctly using a GMail account, however, the mail does not render correctly on the iPhone mail client. On the iPhone mail client, the image is rendered before the "Before Image" text when it should be rendered afterwards. After the "Before Image" text there is an icon with a question mark (I assume it means it couldn't find the referenced CID). I'm not sure if this is a limitation of the iPhone mail client or a bug in my mail sending code (I strongly assume the latter). I think that perhaps the headers on my parts might by incorrect or perhaps I am providing the multiparts in the wrong order. I include the text of the received mail as output by gmail (which renders the file correc Message-ID: <[email protected]> Subject: =?UTF-8?Q?Test_from_=E3=82=AF=E3=83=AA=E3=82=B9?= MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_0_20870565.1274154021755" ------=_Part_0_20870565.1274154021755 Content-Type: application/octet-stream Content-Transfer-Encoding: base64 Content-ID: <20100518124021763_368238_0> iVBORw0K ----- TRIMMED FOR CONCISENESS 6p1VVy4alAAAAABJRU5ErkJggg== ------=_Part_0_20870565.1274154021755 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit <html><head><title>Employees Favourite Foods</title> <style> body { font: normal 8pt arial; } th { font: bold 8pt arial; white-space: nowrap; } td { font: normal 8pt arial; white-space: nowrap; } </style></head><body> Before Image<br><img src="cid:20100518124021763_368238_0"> After Image<br><table border="0"> <tr> <th colspan="4">Employees Favourite Foods</th> </tr> <tr> <th align="left">Name</th><th align="left">Age</th><th align="left">Tel.No</th><th align="left">Fav.Food</th> </tr> <tr style="background-color:#e0e0e0"> <td>Chris</td><td>34</td><td>555-123-4567</td><td>Pancakes</td> </tr> </table></body></html> ------=_Part_0_20870565.1274154021755 Content-Type: text/plain; charset=us-ascii; name=textfile.txt Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=textfile.txt This is a textfile with numbers counting from one to ten beneath this line: one two three four five six seven eight nine ten(no trailing carriage return) ------=_Part_0_20870565.1274154021755-- Even if you can't assist me with this, I would appreciate it if any members of the forum could forward me a (non-personal) mail that includes inline images (not external hyperlinked images though). I just need to find a working sample then I can move past this. Thanks, Chris.

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  • Order of parts in SMTP multipart messages

    - by Chris
    Hi, I'd like to know how to build an SMTP multipart message in the correct order so that it will render correctly on the iPhone mail client (rendering correctly in GMail). I'm using Javamail to build up an email containing the following parts: A body part with content type "text/html; UTF-8" An embedded image attachment. A file attachment I am sending the mail via GMail SMTP (via SSL) and the mail is sent and rendered correctly using a GMail account, however, the mail does not render correctly on the iPhone mail client. On the iPhone mail client, the image is rendered before the "Before Image" text when it should be rendered afterwards. After the "Before Image" text there is an icon with a question mark (I assume it means it couldn't find the referenced CID). I'm not sure if this is a limitation of the iPhone mail client or a bug in my mail sending code (I strongly assume the latter). I think that perhaps the headers on my parts might by incorrect or perhaps I am providing the multiparts in the wrong order. I include the text of the received mail as output by gmail (which renders the file correc Message-ID: <[email protected]> Subject: =?UTF-8?Q?Test_from_=E3=82=AF=E3=83=AA=E3=82=B9?= MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_0_20870565.1274154021755" ------=_Part_0_20870565.1274154021755 Content-Type: application/octet-stream Content-Transfer-Encoding: base64 Content-ID: <20100518124021763_368238_0> iVBORw0K ----- TRIMMED FOR CONCISENESS 6p1VVy4alAAAAABJRU5ErkJggg== ------=_Part_0_20870565.1274154021755 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit <html><head><title>Employees Favourite Foods</title> <style> body { font: normal 8pt arial; } th { font: bold 8pt arial; white-space: nowrap; } td { font: normal 8pt arial; white-space: nowrap; } </style></head><body> Before Image<br><img src="cid:20100518124021763_368238_0"> After Image<br><table border="0"> <tr> <th colspan="4">Employees Favourite Foods</th> </tr> <tr> <th align="left">Name</th><th align="left">Age</th><th align="left">Tel.No</th><th align="left">Fav.Food</th> </tr> <tr style="background-color:#e0e0e0"> <td>Chris</td><td>34</td><td>555-123-4567</td><td>Pancakes</td> </tr> </table></body></html> ------=_Part_0_20870565.1274154021755 Content-Type: text/plain; charset=us-ascii; name=textfile.txt Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=textfile.txt This is a textfile with numbers counting from one to ten beneath this line: one two three four five six seven eight nine ten(no trailing carriage return) ------=_Part_0_20870565.1274154021755-- Even if you can't assist me with this, I would appreciate it if any members of the forum could forward me a (non-personal) mail that includes inline images (not external hyperlinked images though). I just need to find a working sample then I can move past this. Thanks, Chris.

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  • How do I use accepts_nested_attributes_for?

    - by Angela
    Editing my question for conciseness and to update what I've done: How do I model having multiple Addresses for a Company and assign a single Address to a Contact, and be able to assign them when creating or editing a Contact? I want to use nested attributes to be able to add an address at the time of creating a new contact. That address exists as its own model because I may want the option to drop-down from existing addresses rather than entering from scratch. I can't seem to get it to work. I get a undefined method `build' for nil:NilClass error Here is my model for Contacts: class Contact < ActiveRecord::Base attr_accessible :first_name, :last_name, :title, :phone, :fax, :email, :company, :date_entered, :campaign_id, :company_name, :address_id, :address_attributes belongs_to :company belongs_to :address accepts_nested_attributes_for :address end Here is my model for Address: class Address < ActiveRecord::Base attr_accessible :street1, :street2, :city, :state, :zip has_many :contacts end I would like, when creating an new contact, access all the Addresses that belong to the other Contacts that belong to the Company. So here is how I represent Company: class Company < ActiveRecord::Base attr_accessible :name, :phone, :addresses has_many :contacts has_many :addresses, :through => :contacts end Here is how I am trying to create a field in the View for _form for Contact so that, when someone creates a new Contact, they pass the address to the Address model and associate that address to the Contact: <% f.fields_for :address, @contact.address do |builder| %> <p> <%= builder.label :street1, "Street 1" %> </br> <%= builder.text_field :street1 %> <p> <% end %> When I try to Edit, the field for Street 1 is blank. And I don't know how to display the value from show.html.erb. At the bottom is my error console -- can't seem to create values in the address table: My Contacts controller is as follows: def new @contact = Contact.new @contact.address.build # Iundefined method `build' for nil:NilClass @contact.date_entered = Date.today @campaigns = Campaign.find(:all, :order => "name") if params[:campaign_id].blank? else @campaign = Campaign.find(params[:campaign_id]) @contact.campaign_id = @campaign.id end if params[:company_id].blank? else @company = Company.find(params[:company_id]) @contact.company_name = @company.name end end def create @contact = Contact.new(params[:contact]) if @contact.save flash[:notice] = "Successfully created contact." redirect_to @contact else render :action => 'new' end end def edit @contact = Contact.find(params[:id]) @campaigns = Campaign.find(:all, :order => "name") end Here is a snippet of my error console: I am POSTING the attribute, but it is not CREATING in the Address table.... Processing ContactsController#create (for 127.0.0.1 at 2010-05-12 21:16:17) [POST] Parameters: {"commit"="Submit", "authenticity_token"="d8/gx0zy0Vgg6ghfcbAYL0YtGjYIUC2b1aG+dDKjuSs=", "contact"={"company_name"="Allyforce", "title"="", "campaign_id"="2", "address_attributes"={"street1"="abc"}, "fax"="", "phone"="", "last_name"="", "date_entered"="2010-05-12", "email"="", "first_name"="abc"}} Company Load (0.0ms)[0m [0mSELECT * FROM "companies" WHERE ("companies"."name" = 'Allyforce') LIMIT 1[0m Address Create (16.0ms)[0m [0;1mINSERT INTO "addresses" ("city", "zip", "created_at", "street1", "updated_at", "street2", "state") VALUES(NULL, NULL, '2010-05-13 04:16:18', NULL, '2010-05-13 04:16:18', NULL, NULL)[0m Contact Create (0.0ms)[0m [0mINSERT INTO "contacts" ("company", "created_at", "title", "updated_at", "campaign_id", "address_id", "last_name", "phone", "fax", "company_id", "date_entered", "first_name", "email") VALUES(NULL, '2010-05-13 04:16:18', '', '2010-05-13 04:16:18', 2, 2, '', '', '', 5, '2010-05-12', 'abc', '')[0m

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