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• Drop target - where do I register the COleDropTarget variable if the view class doesn't have OnCreat

  - by Harvey

  The MSDN site says: From your view class's function that handles the WM_CREATE message (typically OnCreate), call the new member variable's Register member function. Revoke will be called automatically for you when your view is destroyed. But I don't have an OnCreate function in the ChildView class. I do have OnCreate in the CMainFrame class. Can I register it there? What are the ramifications? PLEASE NOTE: I have it working for dropping files but I want to drop the text as a file, not at a cursor location like a text cut and paste, but rather I want the application to make a buffer to hold it, and I will treat it like a file. TIA, Harvey

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• designing an API wrapper for Twitter, Facebook, Youtube etc...

  - by John Stewart

  I am looking at some pointers on how to design a wrapper for these social networking sites. Ideally what I want to do is create a black box where I am able to create an interface for other libraries to call certain functions to interact with these social networking sites. I am planning on using oAuth for most of these sites, I already have this layer designed in PHP. The other layer that I need for these social sites is the ability to push and pull content. For example, the ability to pull feeds for users from each of these networks and then should I cache them on my end? how would I cache all twitter, facebook etc activity feed and be able to account for resync etc? The networks that I am looking at are: Twitter Youtube Facebook LinkedIN Vimeo Flickr I am looking for ideas on how to tackle this in php? Any suggestions, opensource systems that I can learn from?

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• How can I include platform-specific native libraries in the .JAR file using Eclipse?

  - by Martin Wiboe

  Hello all, I am just starting to learn JNI. I have been following a simple example, and I have created a Java app that calls a Hello World method in a native library. I'd like to target Win32 and Linux x86. My library resides in a DLL, and I can call it just fine using LoadLibrary when the DLL is added to the root of my Eclipse project. However, I can't figure out how to get Eclipse to export a runnable JAR that includes the DLL and the .SO file for Linux. So my question is basically; how would you go about creating a project in Eclipse and include several versions of the same native library? Thank you, Martin

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• Extending Ruby, calling a function from C

  - by ThePower

  Hi, I'm writing an app that calls ruby code from c. I am having a little difficulty and wondered if anyone could point me in the rite direction. I currently have in my C. #include ruby.h main() { ruby_init(); rb_require("myRubyFile"); rb_funcall(rb_module_new(), rb_intern("RubyFunction"), 0, NULL); } My ruby file is in the same directory as my c file and is called myRubyFile.rb and contains a definition of the function RubyFunction(). This is a cut down of what I actually want to do, just making it more readable for others. I just require some feedback as to whether this is the correct method to call ruby code from my c file. Regards

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• Accessing HTTP status code while using WCF client for accessing RESTful services

  - by Hemant

  Thanks to this answer, I am now able to successfully call a JSON RESTful service using a WCF client. But that service uses HTTP status codes to notify the result. I am not sure how I can access those status codes since I just receive an exception on client side while calling the service. Even the exception doesn't have HTTP status code property. It is just buried in the exception message itself. So the question is, how to check/access the HTTP status code of response when the service is called.

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• Javascript - how to change elements content inside a page when using iframes, using dom, not jquery

  - by Erez

  Hello all, I have this iframe and as u can see it call a js function with the onload trigger. <iframe name="top" id="top" width="99%" height="20%" src="top.htm" frameborder="0" scrolling="no" onload="log_in()"></iframe> What i need to do is to effect the element inside "top.htm" (change innerHTML and stuff like that) from that function. But the problem is that the funnction does not recognize the elements of the "top.htm" page, only the ones in index.htm (the page with the iframes). p.s. i have to use DOM and i have to use iframes. Any one knows how to do that? 10x :-)

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• How to avoid Cartesian product in an INNER JOIN query?

  - by flhe

  I have 6 tables, let's call them a,b,c,d,e,f. Now I want to search all the colums (except the ID columns) of all tables for a certain word, let's say 'Joe'. What I did was, I made INNER JOINS over all the tables and then used LIKE to search the columns. INNER JOIN ... ON INNER JOIN ... ON.......etc. WHERE a.firstname ~* 'Joe' OR a.lastname ~* 'Joe' OR b.favorite_food ~* 'Joe' OR c.job ~* 'Joe'.......etc. The results are correct, I get all the colums I was looking for. But I also get some kind of cartesian product, I get 2 or more lines with almost the same results. How can i avoid this? I want so have each line only once, since the results should appear on a web search.

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• Mobile iPhone - Multiple buttons in a row

  - by Thomas

  Hello all: I'm an iPhone developer, but new to web development. I've done some basic HTML websites and made one in iWeb as well. I'm trying to branch out to actual mobile development now, so I checked out Dashcode. Anyway, I'm trying to put a Call Button, Mail Button, and Map Button in horizontal alignment. I realize that I can add a Column Layout and have two buttons in a row, but that's the most I've gotten. Any ideas? Thanks! Thomas

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• How do I solve this error, "error while trying to deserialize parameter"

  - by Paul Rowland

  I have a web service that is working fine in one environment but not in another. The web service gets document meta data from SharePoint, it running on a server where I cant debug but with logging I confirmed that the method enters and exits successfully. What could be the reason for the errors? The error message is, The formatter threw an exception while trying to deserialize the message: There was an error while trying to deserialize parameter http://CompanyName.com.au/ProjectName:GetDocumentMetaDataResponse. The InnerException message was 'Error in line 1 position 388. 'Element' 'CustomFields' from namespace 'http://CompanyName.com.au/ProjectName' is not expected. Expecting element 'Id'.'. Please see InnerException for more details. The InnerException was System.ServiceModel.Dispatcher.NetDispatcherFaultException was caught Message="The formatter threw an exception while trying to deserialize the message: There was an error while trying to deserialize parameter http://CompanyName.com.au/ProjectName:GetDocumentMetaDataResponse. The InnerException message was 'Error in line 1 position 388. 'Element' 'CustomFields' from namespace 'http://CompanyName.com.au/ProjectName' is not expected. Expecting element 'Id'.'. Please see InnerException for more details." Source="mscorlib" Action="http://schemas.microsoft.com/net/2005/12/windowscommunicationfoundation/dispatcher/fault" StackTrace: Server stack trace: at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.DeserializeParameterPart(XmlDictionaryReader reader, PartInfo part, Boolean isRequest) at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.DeserializeParameter(XmlDictionaryReader reader, PartInfo part, Boolean isRequest) at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.DeserializeParameters(XmlDictionaryReader reader, PartInfo[] parts, Object[] parameters, Boolean isRequest) at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.DeserializeBody(XmlDictionaryReader reader, MessageVersion version, String action, MessageDescription messageDescription, Object[] parameters, Boolean isRequest) at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeBodyContents(Message message, Object[] parameters, Boolean isRequest) at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeReply(Message message, Object[] parameters) at System.ServiceModel.Dispatcher.ProxyOperationRuntime.AfterReply(ProxyRpc& rpc) at System.ServiceModel.Channels.ServiceChannel.HandleReply(ProxyOperationRuntime operation, ProxyRpc& rpc) at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs) at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation) at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message) Exception rethrown at [0]: at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) at CompanyName.ProjectName.External.Sharepoint.WebServiceProxies.SharepointProjectNameSiteService.ProjectNameSiteSoap.GetDocumentMetaData(GetDocumentMetaDataRequest request) at CompanyName.ProjectName.External.Sharepoint.WebServiceProxies.SharepointProjectNameSiteService.ProjectNameSiteSoapClient.CompanyName.ProjectName.External.Sharepoint.WebServiceProxies.SharepointProjectNameSiteService.ProjectNameSiteSoap.GetDocumentMetaData(GetDocumentMetaDataRequest request) in D:\Source\TFSRoot\ProjectName\trunk\CodeBase\External\CompanyName.ProjectName.External.Sharepoint.WebServiceProxies\Service References\SharepointProjectNameSiteService\Reference.cs:line 2141 at CompanyName.ProjectName.External.Sharepoint.WebServiceProxies.SharepointProjectNameSiteService.ProjectNameSiteSoapClient.GetDocumentMetaData(ListSummaryDto listSummary, FileCriteriaDto criteria, List`1 customFields) in D:\Source\TFSRoot\ProjectName\trunk\CodeBase\External\CompanyName.ProjectName.External.Sharepoint.WebServiceProxies\Service References\SharepointProjectNameSiteService\Reference.cs:line 2150 at CompanyName.ProjectName.Services.Shared.SharepointAdapter.GetDocumentMetaData(ListSummaryDto listSummary, FileCriteriaDto criteria, List`1 customFields) in D:\Source\TFSRoot\ProjectName\trunk\CodeBase\Services\CompanyName.ProjectName.Services\Shared\SharepointAdapter.cs:line 260 at CompanyName.ProjectName.Services.Project.ProjectDocumentService.SetSharepointDocumentData(List`1 sourceDocuments) in D:\Source\TFSRoot\ProjectName\trunk\CodeBase\Services\CompanyName.ProjectName.Services\Project\ProjectDocumentService.cs:line 1963 at CompanyName.ProjectName.Services.Project.ProjectDocumentService.GetProjectConversionDocumentsImplementation(Int32 projectId) in D:\Source\TFSRoot\ProjectName\trunk\CodeBase\Services\CompanyName.ProjectName.Services\Project\ProjectDocumentService.cs:line 3212 InnerException: System.Runtime.Serialization.SerializationException Message="Error in line 1 position 388. 'Element' 'CustomFields' from namespace 'http://CompanyName.com.au/ProjectName' is not expected. Expecting element 'Id'." Source="System.Runtime.Serialization" StackTrace: at System.Runtime.Serialization.XmlObjectSerializerReadContext.ThrowRequiredMemberMissingException(XmlReaderDelegator xmlReader, Int32 memberIndex, Int32 requiredIndex, XmlDictionaryString[] memberNames) at System.Runtime.Serialization.XmlObjectSerializerReadContext.GetMemberIndexWithRequiredMembers(XmlReaderDelegator xmlReader, XmlDictionaryString[] memberNames, XmlDictionaryString[] memberNamespaces, Int32 memberIndex, Int32 requiredIndex, ExtensionDataObject extensionData) at ReadFileMetaDataDtoFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString[] , XmlDictionaryString[] ) at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context) at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader) at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, DataContract& dataContract) at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 id, RuntimeTypeHandle declaredTypeHandle, String name, String ns) at ReadArrayOfFileMetaDataDtoFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString , XmlDictionaryString , CollectionDataContract ) at System.Runtime.Serialization.CollectionDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context) at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader) at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, DataContract& dataContract) at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 id, RuntimeTypeHandle declaredTypeHandle, String name, String ns) at ReadMetaDataSearchResultsDtoFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString[] , XmlDictionaryString[] ) at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context) at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader) at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, DataContract& dataContract) at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 id, RuntimeTypeHandle declaredTypeHandle, String name, String ns) at ReadGetDocumentMetaDataResponseBodyFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString[] , XmlDictionaryString[] ) at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context) at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader) at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, DataContract& dataContract) at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Type declaredType, DataContract dataContract, String name, String ns) at System.Runtime.Serialization.DataContractSerializer.InternalReadObject(XmlReaderDelegator xmlReader, Boolean verifyObjectName) at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName) at System.Runtime.Serialization.DataContractSerializer.ReadObject(XmlDictionaryReader reader, Boolean verifyObjectName) at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.DeserializeParameterPart(XmlDictionaryReader reader, PartInfo part, Boolean isRequest) InnerException:

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• [PHP] Difference between normal and magic setters and getters

  - by Saif Bechan

  I am using a magic getter/setter class for my session variables, but I don't see any difference between normal setters and getters. The code: class session { public function __set($name, $value) { $_SESSION[$name] = $value; } public function __unset($name) { unset($_SESSION[$name]); } public function __get($name) { if(isset($_SESSION[$name])) { return $_SESSION[$name]; } } } Now the first thing I noticed is that I have to call $session->_unset('var_name') to remove the variable, nothing 'magical' about that. Secondly when I try to use $session->some_var this does not work. I can only get the session variable using $_SESSION['some_var']. I have looked at the PHP manual but the functions look the same as mine. Am I doing something wrong, or is there not really anything magic about these functions.

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• How to set a control ID in ListView Template dynamically?

  - by citronas

  A have a ListView that is rendered with multiple items. Now I want to toggle some HTML attributes with JQuery. Therefore it would be best to have access to these elements via an unique ID. But trying to create a "dynamic" and therefore unique ID by <tr runat="server" ID='<%# this.GetUniqueID() %>'> </tr> results in an error that tells me that the ID needs to be simple and cannot be set by a call to a method. I know that I can dynamically create controls in the code-behind and set the ID there. But in this case, I'd rather like to let the content be rendered by the ListView itself. That brings me to the conclusion that the idea of setting a dynically ID in the Template is totally wrong. How can I achieve the desired behaviour?

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• Nasty deep nested loop in Rails

  - by CalebHC

  I have this nested loop that goes 4 levels deep to find all the image widgets and calculate their sizes. This seems really inefficient and nasty! I have thought of putting the organization_id in the widget model so I could just call something like organization.widgets.(named_scope), but I feel like that's a bad short cut. Is there a better way? Thanks class Organization < ActiveRecord::Base ... def get_image_widget_total total_size = 0 self.trips.each do |t| t.phases.each do |phase| phase.pages.each do |page| page.widgets.each do |widget| if widget.widget_type == Widget::IMAGE total_size += widget.image_file_size end end end end end return total_size end ... end

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• Silverlight -> WCF -> Database -> problem

  - by Billy

  Hi there, I have some silverlight code that calls a WCF service which then uses the Entity Framework to access the database and return records. Everything runs fine but ... when I replace the Entity Framework code with classic ADO.NET code I get an error: The remote server returned an error: NotFound When I call the ADO.NET code directly with a unit test it returns records fine so it's not a problem with the ADO.NEt code I used fiddler and it seems to say that the service cannot be found with a "500" error. i don't think it's anything to do with the service as the only thing I change is the technology to access the database. Anyone know what i'm missing here?

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• PHP pecl/memcached extension slow when setting option for consistent hashing

  - by HarryF

  Using the newer PHP pecl/memcached extension. Calls to Memcached::setOption() like; $m = new Memcached(); $m->setOption(Memcached::OPT_DISTRIBUTION, Memcached::DISTRIBUTION_CONSISTENT); are costing between 150 to 500ms - just in making the call to setOption() and as we're not using persistent connections but rather doing this on every request, it hurts. Delving deeper, setting Memcached::OPT_DISTRIBUTION to Memcached::DISTRIBUTION_CONSISTENT ends up calling update_continuum() in libmemcached which appears to be fairly intensive, although we're only passing a list of 15 memcached servers in, so somewhat surprising to see it take between 150 to 500ms to rebuild the continuum data structure. Could it be setting this option is only suitable for persistent connections, where it's called only once while making the initial connection? Or is this a bug libmemcached? Using the newer pecl/memcached extension 1.0.1 with libmemcached 0.38 Thanks.

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• Mibble MIB Parser - extracting comments from the mib.

  - by this.matt

  I am using the Mibble MIB Parser to extract all simple data types from an MIB file. I've been successful until my attempt to extract comment text. Take the following module as an example: invBookList OBJECT-TYPE SYNTAX INTEGER { mobydick(1), -- call me ishmael paradiselost(2), -- aComment 1984(3), -- aComment solaris(4) -- aComment } MAX-ACCESS read-only STATUS current DESCRIPTION "A few Books for an example." ::= { invMasterList 43 } According to Mibble's API, the OBJECT-TYPE can be accessed by extracting an SnmpObjectType and then calling the appropriate getter method. Which I have done, and can successfully extract all of the text except the comments in the INTEGER syntax. I have tried calling getSyntax().getComment() on the SnmpObjectType, but always returns null. getSyntax() will extract the INTEGER syntax, e.g.: mobydick(1),paradiselist(2),1984(3),solaris(4) but unfortunately strips out the comments. Any one out there have experience with Mibble Parser who knows how to extract the comments? Many Thanks.

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• Matching n parentheses in perl regex

  - by coding_hero

  Hi, I've got some data that I'm parsing in Perl, and will be adding more and more differently formatted data in the near future. What I would like to do is write an easy-to-use function, that I could pass a string and a regex to, and it would return anything in parentheses. It would work something like this (pseudocode): sub parse { $data = shift; $regex = shift; $data =~ eval ("m/$regex/") foreach $x ($1...$n) { push (@ra, $x); } return \@ra; } Then, I could call it like this: @subs = parse ($data, '^"([0-9]+)",([^:]*):(\W+):([A-Z]{3}[0-9]{5}),ID=([0-9]+)'); As you can see, there's a couple of issues with this code. I don't know if the eval would work, the 'foreach' definitely wouldn't work, and without knowing how many parentheses there are, I don't know how many times to loop. This is too complicated for split, so if there's another function or possibility that I'm overlooking, let me know. Thanks for your help!

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• jQuery.ajax checking if there is already another xhr

  - by digitalFresh

  I have a page when, if the user is near the bottom of the page, loads the next page. I just recently switched it to jQuery, and now use the jQuery.ajax() function to get the data. However, now i cannot check if the xhr is already loading, making the page load multiple xhrs when the user near the bottom. My listener is: $(document).scroll(function () { if(/* scrollbar is near bottom */) loadxhr(dat++); //function that calls jQuery.ajax() } }); Basically, can you track the readyState of the call in a global scope?

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• How to trigger saved password autofill in browsers?

  - by Aleksander Kmetec

  I have a web application written in pure JavaScript (no pre-generated HTML except for the document which loads all the JS files). This app contains a login form which is created dynamically when the document.ready event event is triggered. I trick the browser into displaying the "Remember password?" dialog by posting the login form into a hidden iframe before logging in using ajax (in Firefox the password appears on the saved password list, so this part obviously works) but saved passwords never get filled in after the login screen is loaded again at a later time. The same thing happens in Firefox and Safari. Is there something I can do or some function I can call to trigger autofill? UPDATE: autofill works in Safari on initial page load, but not when user logs out and the login form is recreated without a page reload. In Firefox it never works.

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• How to read special characters from stdin in Python?

  - by erickrf

  I'm having trouble reading special characters from stdin. Here are my attempts: import os dir = raw_input("Dir name: ") Dir name: c:/á os.chdir(dir) WindowsError: [Error 2] The system cannot find the file specified: 'c:/\x81\xe1' Ok, so I tried to get the default system encoding and recode the string from stdin: import locale encoding = locale.getdefaultlocale()[1] print encoding cp1252 unicode(dir, encoding) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "c:\Python26\lib\encodings\cp1252.py", line 15, in decode return codecs.charmap_decode(input,errors,decoding_table) UnicodeDecodeError: 'charmap' codec can't decode byte 0x81 in position 3: character maps to <undefined> Now, I don't know how to solve this. Nor can I understand - why is there a problem when I try to access a directory with a name written in the system default encoding itself??

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• php array in url from json

  - by mcgrailm

  Here is what I want to do: I have some json like this var foo = { format:"json", type:"test", id:"26443" }; and I awant to put that in a url like this 'http://example.com/a:3:{s:6:"format";s:4:"json";s:4:"type";s:5:"test";s:2:"id";s:5:"26443";}' which I will then put into ajax call but everything I have tried results in error 501 BAD URI could someone tell me how to do this I've tried this function js_array_to_php_array(a) { var a_php = ""; var total = 3; for (var key in a){ total; a_php = a_php + "s:" + String(key).length + ":\"" + String(key) + "\";s:" + String(a[key]).length + ":\"" + String(a[key]) + "\";"; } a_php = "a:" + total +":{" + a_php + "}"; return a_php; } which I found out on the web but had to mod to get to run but still no luck

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• word frequency problem

  - by davit-datuashvili

  hi in programming pearls i have meet following problem question is this:print words in decreasing frequency or as i understand probllem is this suppose there is given string array let call it s words i have taken randomly it does not matter String s[]={"cat","cat","dog","fox","cat","fox","dog","cat","fox}; and we see that string cat occurs 4 times fox 3 times and dog 2 times so result will be such cat fox dog i have following code in java mport java.util.*; public class string { public static void main(String[] args){ String s[]={"fox","cat","cat","fox","dog","cat","fox","dog","cat"}; Arrays.sort(s); int counts; int count[]=new int[s.length]; for (int i=0;i } } or i have sorted array and create count array where i write number of each word in array problem is that somehow index of integer array element and string array element is not same how to do such that print words according tu maximum elements of integer array? please help me

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• C# 4: conflicting overloaded methods with optional parameters

  - by Thomas

  I have two overloaded methods, one with an optional parameter. void foo(string a) { } void foo(string a, int b = 0) { } now I call: foo("abc"); interestingly the first overload is called. why not the second overload with optional value set to zero? To be honest, I would have expect the compiler to bring an error, at least a warning to avoid unintentional execution of the wrong method. What's the reason for this behaviour? Why did the C# team define it that way? Thanks for your opinions!

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• "Filtering" Cells in a UITableView. Multiple Views? Subviews?

  - by Bryan Veloso

  (First question related to iPhone development, so apologies for sounding off-track.) I'm creating a view that has a few things; a UITabBarController controlling 3 UITableViews. Two of these TableViews are filtered versions of the 3rd. All of them will be making a JSON call (still working on that) to retrieve a list of objects. So, because these views are related in some way, would there be a more "sane" way to display this data? With say, subviews? Or would I have to just create 1 view for each that returns the desired data and be done with it? If it helps at all, I have full control over the API I'm talking with, so changes to that that help with this don't really matter to me too much. Thanks in advance!

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• How do i use findAll method with a class in Doctrine?

  - by terrani

  Hi, I am a little bit confused with Doctrine class. I created a class and its base class in Doctrine. The class's name is User. so..I created an object of class User. $oUser = new User(); when I try to use findAll method, it does not work. I found the following code on the doctrine documentation. Doctrine_Core::getTable('User')-findAll(); I don't understand why i need to call getTable to use findAll method when I have User class. Am I missing something?

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• Using WeakReference to resolve issue with .NET unregistered event handlers causing memory leaks.

  - by Eric

  The problem: Registered event handlers create a reference from the event to the event handler's instance. If that instance fails to unregister the event handler (via Dispose, presumably), then the instance memory will not be freed by the garbage collector. Example: class Foo { public event Action AnEvent; public void DoEvent() { if (AnEvent != null) AnEvent(); } } class Bar { public Bar(Foo l) { l.AnEvent += l_AnEvent; } void l_AnEvent() { } } If I instantiate a Foo, and pass this to a new Bar constructor, then let go of the Bar object, it will not be freed by the garbage collector because of the AnEvent registration. I consider this a memory leak, and seems just like my old C++ days. I can, of course, make Bar IDisposable, unregister the event in the Dispose() method, and make sure to call Dispose() on instances of it, but why should I have to do this? I first question why events are implemented with strong references? Why not use weak references? An event is used to abstractly notify an object of changes in another object. It seems to me that if the event handler's instance is no longer in use (i.e., there are no non-event references to the object), then any events that it is registered with should automatically be unregistered. What am I missing? I have looked at WeakEventManager. Wow, what a pain. Not only is it very difficult to use, but its documentation is inadequate (see http://msdn.microsoft.com/en-us/library/system.windows.weakeventmanager.aspx -- noticing the "Notes to Inheritors" section that has 6 vaguely described bullets). I have seen other discussions in various places, but nothing I felt I could use. I propose a simpler solution based on WeakReference, as described here. My question is: Does this not meet the requirements with significantly less complexity? To use the solution, the above code is modified as follows: class Foo { public WeakReferenceEvent AnEvent = new WeakReferenceEvent(); internal void DoEvent() { AnEvent.Invoke(); } } class Bar { public Bar(Foo l) { l.AnEvent += l_AnEvent; } void l_AnEvent() { } } Notice two things: 1. The Foo class is modified in two ways: The event is replaced with an instance of WeakReferenceEvent, shown below; and the invocation of the event is changed. 2. The Bar class is UNCHANGED. No need to subclass WeakEventManager, implement IWeakEventListener, etc. OK, so on to the implementation of WeakReferenceEvent. This is shown here. Note that it uses the generic WeakReference that I borrowed from here: http://damieng.com/blog/2006/08/01/implementingweakreferencet I had to add Equals() and GetHashCode() to his class, which I include below for reference. class WeakReferenceEvent { public static WeakReferenceEvent operator +(WeakReferenceEvent wre, Action handler) { wre._delegates.Add(new WeakReference<Action>(handler)); return wre; } public static WeakReferenceEvent operator -(WeakReferenceEvent wre, Action handler) { foreach (var del in wre._delegates) if (del.Target == handler) { wre._delegates.Remove(del); return wre; } return wre; } HashSet<WeakReference<Action>> _delegates = new HashSet<WeakReference<Action>>(); internal void Invoke() { HashSet<WeakReference<Action>> toRemove = null; foreach (var del in _delegates) { if (del.IsAlive) del.Target(); else { if (toRemove == null) toRemove = new HashSet<WeakReference<Action>>(); toRemove.Add(del); } } if (toRemove != null) foreach (var del in toRemove) _delegates.Remove(del); } } public class WeakReference<T> : IDisposable { private GCHandle handle; private bool trackResurrection; public WeakReference(T target) : this(target, false) { } public WeakReference(T target, bool trackResurrection) { this.trackResurrection = trackResurrection; this.Target = target; } ~WeakReference() { Dispose(); } public void Dispose() { handle.Free(); GC.SuppressFinalize(this); } public virtual bool IsAlive { get { return (handle.Target != null); } } public virtual bool TrackResurrection { get { return this.trackResurrection; } } public virtual T Target { get { object o = handle.Target; if ((o == null) || (!(o is T))) return default(T); else return (T)o; } set { handle = GCHandle.Alloc(value, this.trackResurrection ? GCHandleType.WeakTrackResurrection : GCHandleType.Weak); } } public override bool Equals(object obj) { var other = obj as WeakReference<T>; return other != null && Target.Equals(other.Target); } public override int GetHashCode() { return Target.GetHashCode(); } } It's functionality is trivial. I override operator + and - to get the += and -= syntactic sugar matching events. These create WeakReferences to the Action delegate. This allows the garbage collector to free the event target object (Bar in this example) when nobody else is holding on to it. In the Invoke() method, simply run through the weak references and call their Target Action. If any dead (i.e., garbage collected) references are found, remove them from the list. Of course, this only works with delegates of type Action. I tried making this generic, but ran into the missing where T : delegate in C#! As an alternative, simply modify class WeakReferenceEvent to be a WeakReferenceEvent, and replace the Action with Action. Fix the compiler errors and you have a class that can be used like so: class Foo { public WeakReferenceEvent<int> AnEvent = new WeakReferenceEvent<int>(); internal void DoEvent() { AnEvent.Invoke(5); } } Hopefully this will help someone else when they run into the mystery .NET event memory leak!

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