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• Converting Generic Type into reference type after checking its type using GetType(). How ?

  - by Shantanu Gupta

  i am trying to call a function that is defined in a class RFIDeas_Wrapper(dll being used). But when i checked for type of reader and after that i used it to call function it shows me error Cannot convert type T to RFIDeas_Wrapper. EDIT private List<string> GetTagCollection<T>(T Reader) { TagCollection = new List<string>(); if (Reader.GetType() == typeof(RFIDeas_Wrapper)) { ((RFIDeas_Wrapper)Reader).OpenDevice(); // here Reader is of type RFIDeas_Wrapper //, but i m not able to convert Reader into its datatype. string Tag_Id = ((RFIDeas_Wrapper)Reader).TagID(); //Adds Valid Tag Ids into the collection if(Tag_Id!="0") TagCollection.Add(Tag_Id); } else if (Reader.GetType() == typeof(AlienReader)) TagCollection = ((AlienReader)Reader).TagCollection; return TagCollection; } ((RFIDeas_Wrapper)Reader).OpenDevice(); , ((AlienReader)Reader).TagCollection; I want this line to be executed without any issue. As Reader will always be of the type i m specifying. How to make compiler understand the same thing.

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• Cannot access Class methods from previous windows form - C#

  - by George

  I am writing an app, still, where I need to test some devices every minute for 30 minutes. It made sense to use a timer set to kick off every 60 secs and do whats required in the event handler. However, I need the app to wait for the 30 mins until I have finished with the timer since the following code alters the state of the devices I am trying to monitor. I obviously don't want to use any form of loop to do this. I thought of using another windows form, since I also display the progress, which will simply kick off the timer and wait until its complete. The problem I am having with this is that I use a device Class and cant seem to get access to the methods in the device class from the 2nd (3rd actually - see below) windows form. I have an initial windows form where I get input from the user, then call the 2nd windows form where it work out which tests need to be done and which device classes need to be used, and then I want to call the 3rd windows form to handle the timer. I will have up to 6-7 device classes and so wanted to only instantiate them when actually requiring them, from the 2nd form. Should I have put this logic into the 1st windows form (program class ??) ? Would I not still have the problem of not being able to access device class methods from there too ? Anyway, perhaps someone knows of a better way to do the checks every minute without the rest of the code executing (and changing the status of the devices) or how I should be accessing the methods in the app ?? Well that's the problem, I cant get that part of it to work correctly. Here is the definition for the calling form including the device class - namespace NdtStart { public partial class fclsNDTCalib : Form { NDTClass NDT = new NDTClass(); public fclsNDTCalib() (new fclsNDTTicker(NDT)).ShowDialog(); Here is the class def for the called form - namespace NdtStart { public partial class fclsNDTTicker : Form { public fclsNDTTicker() I tried lots but couldn't get the arguments to work.

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• Attach Console to Service

  - by MemphiZ

  I currently have a WCF Service Library which will be started through a Console Application acting as ServiceHost. The ServiceHost starts the service and then waits with Console.ReadLine() for the "quit" command. If i do "Console.WriteLine();" in the service this will be printed to the ServiceHosts Console of course. The Service prints some information when the clients connect for example. Is it possible to have the ServiceHost converted to a real Windows Service (to start up when the machine boots without console window) and attach or detach a command prompt (cmd.exe) or another Console Application to it when needed? For example if I want so see which clients connect from now on? Thanks in advance!

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• Pass Linq Expression to a function

  - by Kushan Hasithe Fernando

  I want to pass a property list of a class to a function. with in the function based on property list I'm going to generate a query. As exactly same functionality in Linq Select method. Here I'm gonna implement this for Ingress Database. As an example, in front end I wanna run a select as this, My Entity Class is like this public class Customer { [System.Data.Linq.Mapping.ColumnAttribute(Name="Id",IsPrimaryKey=true)] public string Id { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Name")] public string Name { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Address")] public string Address { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Email")] public string Email { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Mobile")] public string Mobile { get; set; } } I wanna call a Select function like this, var result = dataAccessService.Select<Customer>(C=>C.Name,C.Address); then,using result I can get the Name and Address properties' values. I think my Select function should looks like this, ( *I think this should done using Linq Expression. But im not sure what are the input parameter and return type. * ) Class DataAccessService { // I'm not sure about this return type and input types, generic types. public TResult Select<TSource,TResult>(Expression<Func<TSource,TResult>> selector) { // Here using the property list, // I can get the ColumnAttribute name value and I can generate a select query. } } This is a attempt to create a functionality like in Linq. But im not an expert in Linq Expressions. There is a project call DbLinq from MIT, but its a big project and still i couldn't grab anything helpful from that. Can someone please help me to start this, or can someone link me some useful resources to read about this.

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• Address family not supported by protocol exception

  - by srg

  I'm trying to send a couple of values from an android application to a web service which I've setup. I'm using Http Post to send them but when I run the application I get the error- request time failed java.net.SocketException: Address family not supported by protocol. I get this while debugging with both the emulator as well as a device connected by wifi. I've already added the internet permission using: <uses-permission android:name="android.permission.INTERNET" /> This is the code i'm using to send the values void insertData(String name, String number) throws Exception { String url = "http://192.168.0.12:8000/testapp/default/call/run/insertdbdata/"; HttpClient client = new DefaultHttpClient(); HttpPost post = new HttpPost(url); try { List<NameValuePair> params = new ArrayList<NameValuePair>(2); params.add(new BasicNameValuePair("a", name)); params.add(new BasicNameValuePair("b", number)); post.setEntity(new UrlEncodedFormEntity(params)); HttpResponse response = client.execute(post); }catch(Exception e){ e.printStackTrace(); } Also I know that my web service work fine because when I send the values from an html page it works fine - <form name="form1" action="http://192.168.0.12:8000/testapp/default/call/run/insertdbdata/" method="post"> <input type="text" name="a"/> <input type="text" name="b"/> <input type="submit"/> I've seen questions of similar problems but haven't really found a solution. Thanks

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• Objective-C subclass and base class casting

  - by ryanjm.mp

  I'm going to create a base class that implements very similar functions for all of the subclasses. This was answered in a different question. But what I need to know now is if/how I can cast various functions (in the base class) to return the subclass object. This is both for a given function but also a function call in it. (I'm working with CoreData by the way) As a function within the base class (this is from a class that is going to become my subclass) +(Structure *)fetchStructureByID:(NSNumber *)structureID inContext:(NSManagedObjectContext *)managedObjectContext {...} And as a function call within a given function: Structure *newStructure = [Structure fetchStructureByID:[currentDictionary objectForKey:@"myId"]]; inContext:managedObjectContext]; Structure is one of my subclasses, so I need to rewrite both of these so that they are "generic" and can be applied to other subclasses (whoever is calling the function). How do I do that? Update: I just realized that in the second part there are actually two issues. You can't change [Structure fetch...] to [self fetch...] because it is a class method, not an instance method. How do I get around that too?

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• Stop an executing recursive javascript function

  - by DA

  Using jQuery, I've build an image/slide rotator. The basic setup is (in pseudocode): function setupUpSlide(SlideToStartWith){ var thisSlide = SlideToStartWith; ...set things up... fadeInSlide(thisSlide) } function fadeInSlide(thisSlide){ ...fade in this slide... fadeOutSlide(thisSlide) } function fadeOutSlide(thisSlide){ ...fade out this slide... setupUpSlide(nextSlide) } I call the first function and pass in a particular slide index, and then it does its thing calling chain of functions which then, in turn, calls the first function again passing in the next index. This then repeats infinitely (resetting the index when it gets to the last item). This works just fine. What I want to do now is allow someone to over-ride the slide show by being able to click on a particular slide number. Therefore, if slide #8 is showing and I click #3, I want the recursion to stop and then call the initial function passing in slide #3, which then, in turn, will start the process again. But I'm not sure how to go about that. How does one properly 'break' a recursive script. Should I create some sort of global 'watch' variable that if at any time is 'true' will return: false and allow the new function to execute?

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• Is it important to dispose SolidBrush and Pen?

  - by Joe

  I recently came across this VerticalLabel control on CodeProject. I notice that the OnPaint method creates but doesn't dispose Pen and SolidBrush objects. Does this matter, and if so how can I demonstrate whatever problems it can cause? EDIT This isn't a question about the IDisposable pattern in general. I understand that callers should normally call Dispose on any class that implements IDisposable. What I want to know is what problems (if any) can be expected when GDI+ object are not disposed as in the above example. It's clear that, in the linked example, OnPaint may be called many times before the garbage collector kicks in, so there's the potential to run out of handles. However I suspect that GDI+ internally reuses handles in some circumstances (for example if you use a pen of a specific color from the Pens class, it is cached and reused). What I'm trying to understand is whether code like that in the linked example will be able to get away with neglecting to call Dispose. And if not, to see a sample that demonstrated what problems it can cause. I should add that I have very often (including the OnPaint documentation on MSDN) seen WinForms code samples that fail to dispose GDI+ objects.

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• MySQL db Audit Trail Trigger

  - by Natkeeran

  I need to track changes (audit trail) in certain tables in a MySql Db. I am trying to implement the solution suggested here. I have an AuditLog Table with the following columns: AuditLogID, TableName, RowPK, FieldName, OldValue, NewValue, TimeStamp. The mysql stored procedure is the following (this executes fine, and creates the procedure): The call to the procedure such as: CALL addLogTrigger('ProductTypes', 'ProductTypeID'); executes, but does not create any triggers (see the image). SHOW TRIGGERS returns empty set. Please let me know what could be the issue, or an alternate way to implement this. DROP PROCEDURE IF EXISTS addLogTrigger; DELIMITER $ CREATE PROCEDURE addLogTrigger(IN tableName VARCHAR(255), IN pkField VARCHAR(255)) BEGIN SELECT CONCAT( 'DELIMITER $\n', 'CREATE TRIGGER ', tableName, '_AU AFTER UPDATE ON ', tableName, ' FOR EACH ROW BEGIN ', GROUP_CONCAT( CONCAT( 'IF NOT( OLD.', column_name, ' <=> NEW.', column_name, ') THEN INSERT INTO AuditLog (', 'TableName, ', 'RowPK, ', 'FieldName, ', 'OldValue, ', 'NewValue' ') VALUES ( ''', table_name, ''', NEW.', pkField, ', ''', column_name, ''', OLD.', column_name, ', NEW.', column_name, '); END IF;' ) SEPARATOR ' ' ), ' END;$' ) FROM information_schema.columns WHERE table_schema = database() AND table_name = tableName; END$ DELIMITER ;

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• Creating a simple command line interface (CLI) using a python server (TCP sock) and few scripts

  - by VN44CA

  I have a Linux box and I want to be able to telnet into it (port 77557) and run few required commands without having to access to the whole Linux box. So, I have a server listening on that port, and echos the entered command on the screen. (for now) Telnet 192.168.1.100 77557 Trying 192.168.1.100... Connected to 192.168.1.100. Escape character is '^]'. hello<br /> You typed: "hello"<br /> NOW: I want to create lot of commands that each take some args and have error codes. Anyone has done this before? It would be great if I can have the server upon initialization go through each directory and execute the init.py file and in turn, the init.py file of each command call into a main template lib API (e.g. RegisterMe()) and register themselves with the server as function call backs. At least this is how I would do it in C/C++. But I want the best Pythonic way of doing this. /cmd/ /cmd/myreboot/ /cmd/myreboot/ini.py (note underscore don't show for some reason) /cmd/mylist/ /cmd/mylist/init.py ... etc IN: /cmd/myreboot/_ini_.py: from myMainCommand import RegisterMe RegisterMe(name="reboot",args=Arglist, usage="Use this to reboot the box", desc="blabla") So, repeating this creates a list of commands and when you enter the command in the telnet session, then the server goes through the list, matches the command and passed the args to that command and the command does the job and print the success or failure to stdout. Thx

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• What OOP pattern to use when only adding new methods, not data?

  - by Jonathon Reinhart

  Hello eveyone... In my app, I have deal with several different "parameters", which derive from IParameter interface, and also ParamBase abstract base class. I currently have two different parameter types, call them FooParameter and BarParameter, which both derive from ParamBase. Obviously, I can treat them both as IParameters when I need to deal with them generically, or detect their specific type when I need to handle their specific functionality. My question lies in specific FooParameters. I currently have a few specific ones with their own classes which derive from FooParameter, we'll call them FP12, FP13, FP14, etc. These all have certain characteristics, which make me treat them differently in the UI. (Most have names associated with the individual bits, or ranges of bits). Note that these specific, derived FP's have no additional data associated with them, only properties (which refer to the same data in different ways) or methods. Now, I'd like to keep all of these parameters in a Dictionary<String, IParameter> for easy generic access. The problem is, if I want to refer to a specific one with the special GUI functions, I can't write: FP12 fp12 = (FP12)paramList["FP12"] because you can't downcast to a derived type (rightfully so). But in my case, I didn't add any data, so the cast would theoretically work. What type of programming model should I be using instead? Thanks!

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• Correct Delphi compiler switches to stop in the user's code, not my component's

  - by Jeremy Mullin

  I'm modifying our VCL components so the end user's application links to our dcu files, instead of building our source code each time. We have everything working, but I want the debugger to stop on the user's code when an exception is raised. At first it would stop in our dcu and open the CPU window. I was able to prevent that by removing debug info from the dcu files. But now it still doesn't stop in the users code (like DevExpress libraries and others do). The following screencast is a short example. The first time I cause an exception in the DevExpress code, and the debugger correctly stops in my button event. The second time I cause an exception in my components, but the debugger doesn't have my button event on the call stack, and doesn't show me where the problem was. Any ideas why? http://screencast.com/t/NjhlOTRk Currently building the DCU's with these options: -$W+ -$D- -h -w -q Update: The TDataSet methods in between my component and the button event seem to cause this behavior. If I instead call a direct method of my table, I get the expected behavior. I'm guessing there isn't anything I can do about this, but I'm still curious why it happens.

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• Inereritance of clousure objects and overriding of methods

  - by bobikk

  I need to extend a class, which is encapsulated in a closure. This base class is following: var PageController = (function(){ // private static variable var _current_view; return function(request, new_view) { ... // priveleged public function, which has access to the _current_view this.execute = function() { alert("PageController::execute"); } } })();` Inheritance is realised using the following function: function extend(subClass, superClass){ var F = function(){ }; F.prototype = superClass.prototype; subClass.prototype = new F(); subClass.prototype.constructor = subClass; subClass.superclass = superClass.prototype; StartController.cache = ''; if (superClass.prototype.constructor == Object.prototype.constructor) { superClass.prototype.constructor = superClass; } } I subclass the PageController: var StartController = function(request){ // calling the constructor of the super class StartController.superclass.constructor.call(this, request, 'start-view'); } // extending the objects extend(StartController, PageController); // overriding the PageController::execute StartController.prototype.execute = function() { alert('StartController::execute'); } Inheritance is working. I can call every PageController's method from StartController's instance. However, method overriding doesn't work: var startCont = new StartController(); startCont.execute(); alerts "PageController::execute". How should I override this method?

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• Why is this linq extension method hit the database twice?

  - by Pure.Krome

  Hi folks, I have an extension method called ToListIfNotNullOrEmpty(), which is hitting the DB twice, instead of once. The first time it returns one result, the second time it returns all the correct results. I'm pretty sure the first time it hits the database, is when the .Any() method is getting called. here's the code. public static IList<T> ToListIfNotNullOrEmpty<T>(this IEnumerable<T> value) { if (value.IsNullOrEmpty()) { return null; } if (value is IList<T>) { return (value as IList<T>); } return new List<T>(value); } public static bool IsNullOrEmpty<T>(this IEnumerable<T> value) { if (value != null) { return !value.Any(); } return true; } I'm hoping to refactor it so that, before the .Any() method is called, it actually enumerates through the entire list. If i do the following, only one DB call is made, because the list is already enumerated. var pewPew = (from x in whatever select x) .ToList() // This enumerates. .ToListIsNotNullOrEmpty(); // This checks the enumerated result. I sorta don't really want to call ToList() then my extension method. Any ideas, folks?

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• django test client trouble

  - by Anton Koval'

  I've got a problem... we're writing project using django, and i'm trying to use django.test.client with nose test-framework for tests. Our code is like this: from simplejson import loads from urlparse import urljoin from django.test.client import Client TEST_URL = "http://smakly.localhost:9090/" def test_register(): cln = Client() ref_data = {"email": "[email protected]", "name": "???????", "website": "http://hot.bear.com", "xhr": "true"} print urljoin(TEST_URL, "/accounts/register/") response = loads(cln.post(urljoin(TEST_URL, "/accounts/register/"), ref_data)) print response["message"] and in nose output I catch: Traceback (most recent call last): File "/home/psih/work/svn/smakly/eggs/nose-0.11.1-py2.6.egg/nose/case.py", line 183, in runTest self.test(*self.arg) File "/home/psih/work/svn/smakly/src/smakly.tests/smakly/tests/frontend/test_profile.py", line 25, in test_register response = loads(cln.post(urljoin(TEST_URL, "/accounts/register/"), ref_data)) File "/home/psih/work/svn/smakly/parts/django/django/test/client.py", line 313, in post response = self.request(**r) File "/home/psih/work/svn/smakly/parts/django/django/test/client.py", line 225, in request response = self.handler(environ) File "/home/psih/work/svn/smakly/parts/django/django/test/client.py", line 69, in __call__ response = self.get_response(request) File "/home/psih/work/svn/smakly/parts/django/django/core/handlers/base.py", line 78, in get_response urlconf = getattr(request, "urlconf", settings.ROOT_URLCONF) File "/home/psih/work/svn/smakly/parts/django/django/utils/functional.py", line 273, in __getattr__ return getattr(self._wrapped, name) AttributeError: 'Settings' object has no attribute 'ROOT_URLCONF' My settings.py file does have this attribute. If I get the data from the server with standard urllib2.urllopen().read() it works in the proper way. Any ideas how I can solve this case?

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• Subclassing ViewPager Breaks Animation

  - by Ryan Thomas

  In my Android application I have an activity which uses a view pager to display 4+ pages (Fragments). I implemented buttons on each screen that move between pages by calling: pager.setCurrentItem(position, true); The view pager and fragments are all working as I desired. I then began looking for a solution to disable user swiping between pages so that the transition between pages in handled by the buttons only. The solution I found was mentioned in a few stackoverflow articles as well as This Blog that suggest subclassing the view pager to intercept touch events to disable swiping. I followed those examples by subclassing the view pager class as follows: public class ViewPager extends android.support.v4.view.ViewPager { private boolean enabled; public ViewPager(Context context, AttributeSet attrs) { super(context, attrs); this.enabled = true; } @Override public boolean onTouchEvent(MotionEvent event) { if (this.enabled) { return super.onTouchEvent(event); } return false; } @Override public boolean onInterceptTouchEvent(MotionEvent event) { if (this.enabled) { return super.onInterceptTouchEvent(event); } return false; } public void setSwipingEnabled(boolean enabled) { this.enabled = enabled; } } Using the subclassed view pager and calling setSwipingEnabled(false) works as was desired. The user can no longer move between pages with swipe gestures and I can still move between pages via button clicks by calling setCurrentItem(int position, boolean smoothScroll). However using the subclass breaks the animation between pages. When I call setCurrentItem(position, true) with android.support.v4.view.ViewPager I get very clean scrolling animations between pages. When I make the same call using the subclass the screen has a very brief 'flash' and then automatically draws the new page. I would like to know how to fix the animation while retaining the ability to disable user swiping between pages. I greatly appreciate any help with this. Let me know if you need any additional information. So far I have tested using a Samsung device running 2.3.5 and an AVD emulator targeting Android 2.3.3.

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• PHP: how to access variables inside a function that have been declared outside of it?

  - by Chris

  Please, I am very new and have not been confronted with OOP and all this related stuff, which I guess may be related to this issue (public, private, ...). So, any help and suggestions are very appreciated! :) At the very beginning of each page I include a file that starts the SESSION etc, lets call it session.php. In this file session.php, I include a file that contains a function, let's call it function1.php, because I need the function to be available in session.php. However, later in the main page I also include function2.php which needs to access variables set in session.php, so I additionally tried to include session.php in function2.php. The problem is that an error occurs as function1 will be declared multiple times... Fatal error: Cannot redeclare function1() (previously declared in ... So, what would be a more elegant and clean(er) solution for this? How could you solve it? Basically, I'd need to access variables inside a function that have been included in the main page before... Thank you very much in advance!

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• OnConnect event not firing when using TClientSocket inside a TThread on non-blocking mode

  - by mathematician1975

  I am trying to make use of Borlands TClientSocket component in non-blocking mode inside a multithreaded C++ Windows application. I am creating multiple threads (classes derived from TThread), each of which creates its own TClientSocket object. I then assign member functions of the thread class to act as event handlers for the OnConnect, OnDisconnect and OnSocketError events of the socket. The problem I am having here is that whenever I call the TClientSocket::Open() function from within the TThread::Execute() function, the OnConnect event never fires. However, When I call the Open() function from the VCL thread prior to the TThread::Execute() function getting called, all of the events fire and I can use the thread-socket combination as I would like. Now I have not read anything in documentation that says that TClientSocket should not be used in non-blocking mode when used inside a thread, but it appears to me that there is perhaps something wrong conceptually in the way I am trying to use this class. Borland documentation is quite poor on the subject and these components have now been deprecated so reliable information is hard to come by. Despite being deprecated I have to use them as there is no alternative in the Builder 6 package I have. Can anyone please advise me if there is a right/wrong way to use TThread and a non-blocking TClientSocket in combination. I have never had problems using it as part of the VCL thread and never had problems using TServerSocket before and I really cannot understand why some events are not firing.

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• std::string insert method has ambiguous overloads?

  - by sdg

  Environment: VS2005 C++ using STLPort 5.1.4. Compiling the following code snippet: std::string copied = "asdf"; char ch = 's'; copied.insert(0,1,ch); I receive an error: Error 1 error C2668: 'stlpx_std::basic_string<_CharT,_Traits,_Alloc>::insert' : ambiguous call to overloaded function It appears that the problem is the insert method call on the string object. The two defined overloads are void insert ( iterator p, size_t n, char c ); string& insert ( size_t pos1, size_t n, char c ); But given that STLPort uses a simple char* as its iterator, the literal zero in the insert method in my code is ambiguous. So while I can easily overcome the problem by hinting such as copied.insert(size_t(0),1,ch); My question is: is this overloading and possible ambiguity intentional in the specification? Or more likely an unintended side-effect of the specific STLPort implementation? (Note that the Microsoft-supplied STL does not have this problem as it has a class for the iterator, instead of a naked pointer)

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• ControlCollection extension method optimazation

  - by Johan Leino

  Hi, got question regarding an extension method that I have written that looks like this: public static IEnumerable<T> FindControlsOfType<T>(this ControlCollection instance) where T : class { T control; foreach (Control ctrl in instance) { if ((control = ctrl as T) != null) { yield return control; } foreach (T child in FindControlsOfType<T>(ctrl.Controls)) { yield return child; } } } public static IEnumerable<T> FindControlsOfType<T>(this ControlCollection instance, Func<T, bool> match) where T : class { return FindControlsOfType<T>(instance).Where(match); } The idea here is to find all controls that match a specifc criteria (hence the Func<..) in the controls collection. My question is: Does the second method (that has the Func) first call the first method to find all the controls of type T and then performs the where condition or does the "runtime" optimize the call to perform the where condition on the "whole" enumeration (if you get what I mean). secondly, are there any other optimizations that I can do to the code to perform better. An example can look like this: var checkbox = this.Controls.FindControlsOfType<MyCustomCheckBox>( ctrl => ctrl.CustomProperty == "Test" ) .FirstOrDefault();

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• C++: calling non-member functions with the same syntax of member ones

  - by peoro

  One thing I'd like to do in C++ is to call non-member functions with the same syntax you call member functions: class A { }; void f( A & this ) { /* ... */ } // ... A a; a.f(); // this is the same as f(a); Of course this could only work as long as f is not virtual (since it cannot appear in A's virtual table. f doesn't need to access A's non-public members. f doesn't conflict with a function declared in A (A::f). I'd like such a syntax because in my opinion it would be quite comfortable and would push good habits: calling str.strip() on a std::string (where strip is a function defined by the user) would sound a lot better than calling strip( str );. most of the times (always?) classes provide some member functions which don't require to be member (ie: are not virtual and don't use non-public members). This breaks encapsulation, but is the most practical thing to do (due to point 1). My question here is: what do you think of such feature? Do you think it would be something nice, or something that would introduce more issues than the ones it aims to solve? Could it make sense to propose such a feature to the next standard (the one after C++0x)? Of course this is just a brief description of this idea; it is not complete; we'd probably need to explicitly mark a function with a special keyword to let it work like this and many other stuff.

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• Sweave can't see a vector if run from a function ?

  - by PaulHurleyuk

  I have a function that sets a vector to a string, copies a Sweave document with a new name and then runs that Sweave. Inside the Sweave document I want to use the vector I set in the function, but it doesn't seem to see it. (Edit: I changed this function to use tempdir(() as suggested by Dirk) I created a sweave file test_sweave.rnw; % \documentclass[a4paper]{article} \usepackage[OT1]{fontenc} \usepackage{Sweave} \begin{document} \title{Test Sweave Document} \author{gb02413} \maketitle <<>>= ls() Sys.time() print(paste("The chosen study was ",chstud,sep="")) @ \end{document} and I have this function; onOK <- function(){ chstud<-"test" message(paste("Chosen Study is ",chstud,sep="")) newfile<-paste(chstud,"_report",sep="") mypath<-paste(tempdir(),"\\",sep="") setwd(mypath) message(paste("Copying test_sweave.Rnw to ",paste(mypath,newfile,".Rnw",sep=""),sep="")) file.copy("c:\\local\\test_sweave.Rnw", paste(mypath,newfile,".Rnw",sep=""), overwrite=TRUE) Sweave(paste(mypath,newfile,".Rnw",sep="")) require(tools) texi2dvi(file = paste(mypath,newfile,".tex",sep=""), pdf = TRUE) } If I run the code from the function directly, the resulting file has this output for ls(); > ls() [1] "chstud" "mypath" "newfile" "onOK" However If I call onOK() I get this output; > ls() [1] "onOK" and the print(...chstud...)) function generates an error. I suspect this is an environment problem, but I assumed because the call to Sweave occurs within the onOK function, it would be in the same enviroment, and would see all the objects created within the function. How can I get the Sweave process to see the chstud vector ? Thanks Paul.

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• Event type property lost in IE-8

  - by Channel72

  I've noticed a strange Javascript error which only seems to happen on Internet Explorer 8. Basically, on IE-8 if you have an event handler function which captures the event object in a closure, the event "type" property seems to become invalidated from within the closure. Here's a simple code snippet which reproduces the error: <html> <head> <script type = "text/javascript"> function handleClickEvent(ev) { ev = (ev || window.event); alert(ev.type); window.setTimeout(function() { alert(ev.type); // Causes error on IE-8 }, 20); } function foo() { var query = document.getElementById("query"); query.onclick = handleClickEvent; } </script> </head> <body> <input id = "query" type = "submit"> <script type = "text/javascript"> foo(); </script> </body> </html> So basically, what happens here is that within the handleClickEvent function, we have the event object ev. We call alert(ev.type) and we see the event type is "click". So far, so good. But then when we capture the event object in a closure, and then call alert(ev.type) again from within the closure, now all of a sudden Internet Explorer 8 errors, saying "Member not found" because of the expression ev.type. It seems as though the type property of the event object is mysteriously gone after we capture the event object in a closure. I tested this code snippet on Firefox, Safari and Chrome, and none of them report an error condition. But in IE-8, the event object seems to become somehow invalidated after it's captured in the closure. Question: Why is this happening in IE-8, and is there any workaround?

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• How should we setup up complex situations for tests?

  - by ShaneC

  I'm currently working on what I would call integration tests. I want to verify that if a WCF service is called it will do what I expect. Let's take a very simple scenario. Assume we have a contract object that we can put on hold or take off hold. Now writing the put on hold test is quite simple. You create a contract instance and execute the code that puts it on code. The question I have comes when we want to test the taking off hold service call. The problem is that putting a contract on hold can be actually quite complicated leading to various objects all be modified. So usually I would use the Builder pattern and do something like this.. var onHoldContract = new ContractBuilder().PutOnHold().Build(); The problem I have with this is now I have to pretty much replicate a large part of my put on hold service. Now when I change what putting something on hold means I have two places I have to modify. The other option that immediately jumps out at me is to just use the put on hold service as part of my test setup but now I'm coupling my test to the success of another piece of code which is something I don't like to do since it can lead to failures in one spot breaking unrelated tests elsewhere (if put on hold failed for example). Any other options I'm missing out here? or opinions on which method is preferable and why?

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• Few Basic Questions in Overriding

  - by Dahlia

  I have few problems with my basic and would be thankful if someone can clear this. What does it mean when I say base *b = new derived; Why would one go for this? We very well separately can create objects for class base and class derived and then call the functions accordingly. I know that this base *b = new derived; is called as Object Slicing but why and when would one go for this? I know why it is not advisable to convert the base class object to derived class object (because base class is not aware of the derived class members and methods). I even read in other StackOverflow threads that if this is gonna be the case then we have to change/re-visit our design. I understand all that, however, I am just curious, Is there any way to do this? class base { public: void f(){cout << "In Base";} }; class derived:public base { public: void f(){cout << "In Derived";} }; int _tmain(int argc, _TCHAR* argv[]) { base b1, b2; derived d1, d2; b2 = d1; d2 = reinterpret_cast<derived*>(b1); //gives error C2440 b1.f(); // Prints In Base d1.f(); // Prints In Derived b2.f(); // Prints In Base d1.base::f(); //Prints In Base d2.f(); getch(); return 0; } In case of my above example, is there any way I could call the base class f() using derived class object? I used d1.base()::f() I just want to know if there any way without using scope resolution operator? Thanks a lot for your time in helping me out!

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