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  • Controls added in the designer are null during Page_Load

    - by mwright
    All of the names below are generic and not the actual names used. I have a custom UserControl with a Panel that contains a a couple Labels, both .aspx controls. .aspx: <asp:Panel runat="server"> <asp:Label ID="label1" runat="server"> </asp:Label> </asp:Panel> <asp:Panel runat="server"> <asp:Label ID="label2" runat="server"> </asp:Label> </asp:Panel> Codebehind: private readonly Object object; protected void Page_Load(object sender, EventArgs e) { // These are the lines that are failing // label1 and label2 are null label1.Text = object.Value1; label2.Text = object.Value2; } public ObjectRow(Object objectToDisplay) { object = objectToDisplay; } On another page, in the code behind, I create a new instance of the custom user control. protected void Page_Load(object sender, EventArgs e) { CustomControl control = new CustomControl(object); } The user control takes the parameter and attempts to set the labels based off of the object passed in. The labels that it tries to assign the values to are however, null. Is this an ASP.net lifecycle issue that I'm not understanding? My understanding based on the Microsoft ASP.net lifecycle page was that page controls were available after the Page_Initialization. What is the proper way to do this? Is there a better way?

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  • Throwing exception vs returning null value with switch statement

    - by Greg
    So I have function that formats a date to coerce to given enum DateType{CURRENT, START, END} what would be the best way to handling return value with cases that use switch statement public static String format(Date date, DateType datetype) { ..validation checks switch(datetype){ case CURRENT:{ return getFormattedDate(date, "yyyy-MM-dd hh:mm:ss"); } ... default:throw new ("Something strange happend"); } } OR throw excpetion at the end public static String format(Date date, DateType datetype) { ..validation checks switch(datetype){ case CURRENT:{ return getFormattedDate(date, "yyyy-MM-dd hh:mm:ss"); } ... } //It will never reach here, just to make compiler happy throw new IllegalArgumentException("Something strange happend"); } OR return null public static String format(Date date, DateType datetype) { ..validation checks switch(datetype){ case CURRENT:{ return getFormattedDate(date, "yyyy-MM-dd hh:mm:ss"); } ... } return null; } What would be the best practice here ? Also all the enum values will be handled in the case statement

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  • Is using the Class instance as a Map key a best practice?

    - by Pangea
    I have read somewhere that using the class instances as below is not a good idea as they might cause memory leaks. Can someone tell me if if that is a valid statement? Or are they any problems using it this way? Map<Class<?>,String> classToInstance=new HashMap(); classToInstanceMap.put(String.class,"Test obj");

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  • Interface for classes that have nothing in common

    - by Tomek Tarczynski
    Lets say I want to make few classes to determine behaviour of agents. The good practice would be to make some common interface for them, such interface (simplified) could look like this: interface IModel { void UpdateBehaviour(); } All , or at least most, of such model would have some parameters, but parameters from one model might have nothing in common with parameters of other model. I would like to have some common way of loading parameters. Question What is the best way to do that? Is it maybe just adding method void LoadParameters(object parameters) to the IModel? Or creating empty interface IParameters and add method void LoadParameters(IParameters parameters)? That are two ideas I came up with, but I don't like either of them.

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  • Strategy for unsubscribing event handlers

    - by stiank81
    In my WPF application I have a View that is given a ViewModel, and when given this View it adds event handlers to the ViewModel's PropertyChanged event. When some action occur in the GUI I remove the View and add another View to the holding container - where this new one is bound to the same ViewModel. After this has happened the old View still keeps handling PropertyChanged events in the ViewModel. I'm assuming this happens because the View hasn't been collected by the Garbage Collector yet, and therefore is alive? Well - I need it to stop. My assumption is that I need to manually detach the event handler from the ViewModel? Is there a best-practice on how to handle this?

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  • controlling if exceptions are swallowed by a static boolean

    - by sandis
    So we are a few guys developing this product that is communicating with a really unstable server. It often returns very strange and corrupt data. During testing we want the resulting crashes to be loud, so we discover them. But every other day we need to demonstrate our product for a potential customer. To the customer the errors will go undiscovered if we just swallow them. I am thinking about implementing something like this around all server communication to quickly switch between swallowing exceptions and crashing: try { apiCall(); } catch (Exception e) { if(!SWALLOW_EXCEPTION) { throw e; } } Is this an awesome idea, or can it be done in a better way?

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  • When should you use intermediate variables for expressions?

    - by froadie
    There are times that one writes code such as this: callSomeMethod(someClass.someClassMethod()); And other times when one would write the same code like this: int result = someClass.someClassMethod(); callSomeMethod(result); This is just a basic example to illustrate the point. My question isn't if you should use an intermediate variable or not, as that depends on the code and can sometimes be a good design decision and sometimes a terrible one. The question is - when would you choose one method over the other? What factors would you consider when deciding whether to use an intermediate step? (I'd assume length and understandability of the fully inlined code would have something to do with it...)

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  • Where should I exclude and select information BL or DL?

    - by MRFerocius
    Hi guys; I have another conceptual question. Suppose I have a Data Layer and a Bussines Layer. I have on my data base for example Customers and those customers has an assigned Vendor: Customers(customerID, customerName, customerAddress, vendorID) Vendors(vendorID, vendorName, vendorAddress) Now suppose my Vendor logs into my web application and wants to see all his customers: a) Should I use my Datalayer method and there find his customers on the query? b) Should the data layer return all the customers and on the Buissnes Layer filter that vendor ones? Is B even a good approach because is the one I want to use.... Is it correct? Thanks in advance!!!

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  • How to avoid injecting dependencies into an object so that it can pass them on?

    - by Pheter
    I am interested in applying dependency injection to my current project, which makes use of the MVC pattern. My controllers will call the models and therefore will need to inject the dependencies into the models. To do this, the controller must have the dependencies (such as a database object) in the first place. The controller doesn't need to make use of some of these dependencies (such as the database object), so I feel that it shouldn't be given this dependency. However, it has to have these dependencies if it is to inject them into the model objects. How can I avoid having dependencies injected into an object just so that it can pass them on? Doing so feels wrong and can result in many dependencies being injected into an object. Edit: I am using PHP.

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  • Is it good practice to call module functions directly in VB.NET?

    - by froadie
    I have a Util module in my VB.NET program that has project-wide methods such as logging and property parsing. The general practice where I work seems to be to call these methods directly without prefixing them with Util. When I was new to VB, it took me a while to figure out where these methods/functions were coming from. As I use my own Util methods now, I can't help thinking that it's a lot clearer and more understandable to add Util. before each method call (you know immediately that it's user-defined but not within the current class, and where to find it), and is hardly even longer. What's the general practice when calling procedures/functions of VB modules? Should we prefix them with the module name or not?

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  • Creating/Maintaining a large project-agnostic code library

    - by bufferz
    In order to reduce repetition and streamline testing/debugging, I'm trying to find the best way to develop a group of libraries that many projects can utilize. I'd like to keep individual executable relatively small, and have shared libraries for math, database, collections, graphics, etc. that were previously scattered among several projects and in many cases duplicated (bad!). This library is to be in an SVN repo and several programmers will be working on it. This library will be in constant development along with the executables that utilize it. For example, I want a code file in ProjectA to look something like the following: using MyCompany.Math.2D; //static 2D math methods using MyCompany.Math.3D; //static #D math methods using MyCompany.Comms.SQL; //static methods for doing simple SQLDB I/O using MyCompany.Graphics.BitmapOperations; //static methods that play with bitmaps So in my ProjectA solution file in VisualStudio, in order to develop/debug the MyCompany library I have to add several projects (Math, Comms, Graphics). Things get pretty cluttered and Solution files get out of date quickly between programmer SVN commits. I'm just looking for a high level approach to maintaining a large, shared code base in an SCN repository. I am fully willing to radically redesign my approach. I'm looking for that warm fuzzy feeling you get when you're design approach is spot on and development is fluid and natural. And ideas? Thanks!!

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  • Design Question on when to save

    - by Ben
    Hi, I was just after peoples opinion on when the best time to save an object (or collection of objects) is. I appreciate that it can be completely dependent on the situation that you are in but here is my situation. I have a collection of objects "MyCollection" in a grid. You can open each object "MyObject" in an editor dialogue by double clicking on the grid. Selecting "Cancel" on the dialogue will back out any changes you have made, but should selecting "ok" commit those changes back to the database, or should they commit the changes on that object back to the collection and have a save method that iterates through the collection and saves all changed objects? If i have an object "MyParentObject", that contains a collection of childen "MyChildObjectCollection", none of the changes made to each "MyChildObject" would be commited to the database until the "MyParentObject" was saved - this makes sense. However in my current situation, none of the objects in the collection are linked, therefore should the "Ok" on the dialogue commit the changes to the database? Appreciate any opinions on this. Thanks

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  • What's the most unsound program you've had to maintain?

    - by Robert Rossney
    I periodically am called upon to do maintenance work on a system that was built by a real rocket surgeon. There's so much wrong with it that it's hard to know where to start. No, wait, I'll start at the beginning: in the early days of the project, the designer was told that the system would need to scale, and he'd read that a source of scalability problems was traffic between the application and database servers, so he made sure to minimize this traffic. How? By putting all of the application logic in SQL Server stored procedures. Seriously. The great bulk of the application functions by the HTML front end formulating XML messages. When the middle tier receives an XML message, it uses the document element's tag name as the name of the stored procedure it should call, and calls the SP, passing it the entire XML message as a parameter. It takes the XML message that the SP returns and returns it directly back to the front end. There is no other logic in the application tier. (There was some code in the middle tier to validate the incoming XML messages against a library of schemas. But I removed it, after ascertaining that 1) only a small handful of messages had corresponding schemas, 2) the messages didn't actually conform to these schemas, and 3) after validating the messages, if any errors were encountered, the method discarded them. "This fuse box is a real time-saver - it comes from the factory with pennies pre-installed!") I've seen software that does the wrong thing before. Lots of it. I've written quite a bit. But I've never seen anything like the steely-eyed determination to do the wrong thing, at every possible turn, that's embodied in the design and programming of this system. Well, at least he went with what he knew, right? Um. Apparently, what he knew was Access. And he didn't really understand Access. Or databases. Here's a common pattern in this code: SELECT @TestCodeID FROM TestCode WHERE TestCode = @TestCode SELECT @CountryID FROM Country WHERE CountryAbbr = @CountryAbbr SELECT Invoice.*, TestCode.*, Country.* FROM Invoice JOIN TestCode ON Invoice.TestCodeID = TestCode.ID JOIN Country ON Invoice.CountryID = Country.ID WHERE Invoice.TestCodeID = @TestCodeID AND Invoice.CountryID = @CountryID Okay, fine. You don't trust the query optimizer either. But how about this? (Originally, I was going to post this in What's the best comment in source code you have ever encountered? but I realized that there was so much more to write about than just this one comment, and things just got out of hand.) At the end of many of the utility stored procedures, you'll see code that looks like the following: -- Fix NULLs SET @TargetValue = ISNULL(@TargetValue, -9999) Yes, that code is doing exactly what you can't allow yourself to believe it's doing lest you be driven mad. If the variable contains a NULL, he's alerting the caller by changing its value to -9999. Here's how this number is commonly used: -- Get target value EXEC ap_GetTargetValue @Param1, @Param2, OUTPUT @TargetValue -- Check target value for NULL value IF @TargetValue = -9999 ... Really. For another dimension of this system, see the article on thedailywtf.com entitled I Think I'll Call Them "Transactions". I'm not making any of this up. I swear. I'm often reminded, when I work on this system, of Wolfgang Pauli's famous response to a student: "That isn't right. It isn't even wrong." This can't really be the very worst program ever. It's definitely the worst one I've worked

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  • Procedures before checking in to source control?

    - by Mongus Pong
    I am starting to get a reputation at work as the "guy who breaks the builds". The problem is not that I am writing dodgy code, but when it comes to checking my fixes back into source control, it all goes wrong. I am regularly doing stupid things like : forgetting to add new files accidentally checking in code for a half fixed bug along with another bug fix forgetting to save the files in VS before checking them in I need to develop some habits / tools to stop this. What do you regularly do to ensure the code you check in is correct and is what needs to go in? Edit I forgot to mention that things can get pretty chaotic in this place. I quite often have two or three things that Im working on in the same code base at any one time. When I check in I will only really want to check in one of those things.

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  • do I need to use partial?

    - by wiso
    I've a general function, for example (only a simplified example): def do_operation(operation, a, b, name): print name do_something_more(a,b,name, operation(a,b)) def operation_x(a,b): return a**2 + b def operation_y(a,b): return a**10 - b/2. and some data: data = {"first": {"name": "first summation", "a": 10, "b": 20, "operation": operation_x}, "second": {"name": "second summation", "a": 20, "b": 50, "operation": operation_y}, "third": {"name": "third summation", "a": 20, "b": 50, "operation": operation_x}, # <-- operation_x again } now I can do: what_to_do = ("first", "third") # this comes from command line for sum_id in what_to_do: do_operation(data["operation"], data["a"], data["b"], data["name"]) or maybe it's better if I use functools.partial? from functools import partial do_operation_one = do_operation(name=data["first"]["name"], operation=data["first"]["operation"], a=data["first"]["a"], b=data["first"]["b"]) do_operation_two = do_operation(name=data["second"]["name"], operation=data["second"]["operation"] a=data["second"]["a"], b=data["second"]["b"]) do_operation_three = do_operation(name=data["third"]["name"], operation=data["third"]["operation"] a=data["third"]["a"], b=data["third"]["b"]) do_dictionary = { "first": do_operation_one, "second": do_operation_two, "third": do_operation_three } for what in what_to_do: do_dictionary[what]()

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  • Should I distinguish OpenIDs based on protocol prefix or not? http vs https

    - by Joannes Vermorel
    I have implemented a straightforward OpenID support for my ASP.NET app with DotNetOpenAuth. Yet I recently realized that the implementation was treating http://johndoe.example.com/ as a distinct user compared to https://johndoe.example.com. This lead to quite a few confused users. I am unsure what to do at this point. Is this a bug or a feature? Indeed, I can consider this behavior as a feature: if the user specifies the HTTPS, the user might not want the system to accept HTTP auth in the first place. On the other hand: if the user specifies HTTPS out of sheer cluelessness (the casual web visitor is clueless concerning the purpose of the "S" part), then rejecting it's authentication attempt is confusing. What is considered as the best practice?

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  • c# Attribute Question

    - by Petoj
    Well i need some help here i don't know how to solve this problem. the function of the attribute is to determine if the function can be run... So what i need is the following: The consumer of the attribute should be able to determine if it can be executed. The owner of the attribute should be able to tell the consumer that now it can/can't be executed (like a event). It must have a simple syntax. This is what i have so far but it only implements point 1, 3. [AttributeUsage(AttributeTargets.Method, AllowMultiple = false)] public class ExecuteMethodAttribute : Attribute { private Func<object, bool> canExecute; public Func<object, bool> CanExecute { get { return canExecute; } } public ExecuteMethodAttribute() { } public ExecuteMethodAttribute(Func<object, bool> canExecute) { this.canExecute = canExecute; } }

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  • Proper way in MVVM to drive visual states.

    - by firoso
    Given a content presenter that can display one of 4 different application pages, and I want to fade/otherwise animate a transition between pages based on view model state. Ideally I'd like to have these all defined within a DataTemplate, and then trigger transitions based on an enum from the view model, so that when some enum representing state changes, the transitions trigger to the appropriate page. Is there a known best practice to handle things like this? Immediately coming to mind is the possibiltiy to use Enter and Exit actions on data triggers to play storyboards, but this definately doesn't use the parts and states model, so I'd like to shy away from that. I've also tried using the DataStateSwitchBehavior from the codeplex Expression project, but found it to be incompatable with the latest builds of WPF 4.0/Blend 4 RC's SDK. Does anyone have any ideas on how to handle this elegantly? I'm using the MVVM-Light framework. Also I'd like to point out that as long as this resides on a DataTemplate in a Resource Dictionary, code-behind is not an option without refactoring.

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  • REST doesn't work with Sever-Client-Client setup

    - by drozzy
    I am having a problem with my current RESTful api design. What I have is a REST api which is consumed by Django web-server, which renders the HTML templates. REST api > Django webserver > HTML The problem I am encountering is that I have to reconstruct all the URLS like mysite.com/main/cities/<id>/streets/ into equivalent rest api urls on my web-server layer: api.com/cities/<id>/streets/ Thus I have a lot of mapping back and forth, but as far as I know REST says that the client (in this case my web-server) should NOT need to know how to re-construct the urls. Can REST be used for such a setup and how? Or is it only viable for Server-Client architecture. Thanks

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  • Where to store 3rd party libraries?

    - by zerkms
    I have asp.net mvc 2 application. Now I'm reimplementing it for working with Ninject. All is fine except one thing: where should I store Ninject.dll?? I've created lib directory inside my appdir and made reference to lib/Ninject.dll. But may be there are some general conventions on how to act in such cases?

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