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  • What's the correct way to do a "catch all" error check on an fstream output operation?

    - by Truncheon
    What's the correct way to check for a general error when sending data to an fstream? UPDATE: My main concern regards some things I've been hearing about a delay between output and any data being physically written to the hard disk. My assumption was that the command "save_file_obj << save_str" would only send data to some kind of buffer and that the following check "if (save_file_obj.bad())" would not be any use in determining if there was an OS or hardware problem. I just wanted to know what was the definitive "catch all" way to send a string to a file and check to make certain that it was written to the disk, before carrying out any following actions such as closing the program. I have the following code... int Saver::output() { save_file_handle.open(file_name.c_str()); if (save_file_handle.is_open()) { save_file_handle << save_str.c_str(); if (save_file_handle.bad()) { x_message("Error - failed to save file"); return 0; } save_file_handle.close(); if (save_file_handle.bad()) { x_message("Error - failed to save file"); return 0; } return 1; } else { x_message("Error - couldn't open save file"); return 0; } }

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  • Problem using Lazy<T> from within a generic abstract class

    - by James Black
    I have a generic class that all my DAO classes derive from, which is defined below. I also have a base class for all my entities, but that is not generic. The method GetIdOrSave is going to be a different type than how I defined SabaAbstractDAO, as I am trying to get the primary key to fulfill the foreign key relationships, so this function goes out to either get the primary key or save the entity and then get the primary key. The last code snippet has a solution on how it will work if I get rid of the generic part, so I think this can be solved by using variance, but I can't figure out how to write an interface that will compile. public abstract class SabaAbstractDAO<T> { ... public K GetIdOrSave<K>(K item, Lazy<SabaAbstractDAO<BaseModel>> lazyitemdao) where K : BaseModel { if (item != null && item.Id.IsNull()) { var itemdao = lazyitemdao.Value; item.Id = itemdao.retrieveID(item); if (item.Id.IsNull()) { return itemdao.SaveData(item); } } return item; } } I am getting this error, when I try to compile: Argument 2: cannot convert from 'System.Lazy<ORNL.HRD.LMS.Dao.SabaCourseDAO>' to 'System.Lazy<ORNL.HRD.LMS.Dao.SabaAbstractDAO<ORNL.HRD.LMS.Models.BaseModel>>' I am trying to call it this way: GetIdOrSave(input.OfferingTemplate, new Lazy<SabaCourseDAO>( () => { return new SabaCourseDAO() { Dao = Dao }; }) ); If I change the definition to this, it works. public K GetIdOrSave<K>(K item, Lazy<SabaCourseDAO> lazyitemdao) where K : BaseModel { So, how can I get this to compile using variance (if needed) and generics, so I can have a very general method that will only work with BaseModel and AbstractDAO<BaseModel>? I expect I should only need to make the change in the method and perhaps abstract class definition, the usage should be fine.

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  • Android - Temporal & Ancestral Navigation with ViewPager & Fragments

    - by rascuache
    I'm trying to work out the best way to implement the 'ancestral' and 'temporal' navigation (utilising the up button and back buttons), for a music player I'm working on. Currently, the user is presented with a viewpager, and can page between three main fragments (ArtistMain, AlbumMain and SongMain). Upon choosing an item inside that view, a fragment transaction occurs, and the viewpager goes out of view, replaced by a new fragment (AlbumSub, Songsub or player, depending on where the user came from). The user can then navigate deeper, until a song is chosen, and then they are taken to the 'player' screen. I guess the question is: How do I implement all of this conditional navigation? I'm fairly new to android and programming in general, and I just can't seem to come up with an efficient way to achieve this. At the moment, as each fragment is brought into view, the app is checking to see where the user just came from, and then determines where the user should be taken if back or home is called. This means I have a booleans like "fromArtistMain", "fromAlbumSub", and I'm checking for things like "fromSongSub && fromPlayer".. it's all turning into a bit of a mess. I've drawn a diagram (in paint, sorry!!), to depict the navigation I'm trying to achieve. The yellow represents the 'up' button press, the red is the 'back' button press, and blue is just normal navigation. The green arrows are meant to represent the view paging: Any advice is welcome. It might take something really simple that I've just overlooked. Thanks for your time.

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  • When to choose which machine learning classifier?

    - by LM
    Suppose I'm working on some classification problem. (Fraud detection and comment spam are two problems I'm working on right now, but I'm curious about any classification task in general.) How do I know which classifier I should use? (Decision tree, SVM, Bayesian, logistic regression, etc.) In which cases is one of them the "natural" first choice, and what are the principles for choosing that one? Examples of the type of answers I'm looking for (from Manning et al.'s "Introduction to Information Retrieval book": http://nlp.stanford.edu/IR-book/html/htmledition/choosing-what-kind-of-classifier-to-use-1.html): a. If your data is labeled, but you only have a limited amount, you should use a classifier with high bias (for example, Naive Bayes). [I'm guessing this is because a higher-bias classifier will have lower variance, which is good because of the small amount of data.] b. If you have a ton of data, then the classifier doesn't really matter so much, so you should probably just choose a classifier with good scalability. What are other guidelines? Even answers like "if you'll have to explain your model to some upper management person, then maybe you should use a decision tree, since the decision rules are fairly transparent" are good. I care less about implementation/library issues, though. Also, for a somewhat separate question, besides standard Bayesian classifiers, are there 'standard state-of-the-art' methods for comment spam detection (as opposed to email spam)? [Not sure if stackoverflow is the best place to ask this question, since it's more machine learning than actual programming -- if not, any suggestions for where else?]

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  • AI navigation around a 2d map - Avoiding obstacles.

    - by Curt Walker
    Hey there, I know my question seems pretty vague but I can't think of a better way to put it so I'll start off by explaining what I'm trying to do. I'm currently working on a project whereby I've been given a map and I'm coding a 'Critter' that should be able to navigate it's way around the map, the critter has various other functions but are not relevant to the current question. The whole program and solution is being written in C#. I can control the speed of the critter, and retrieve it's current location on the map by returning it's current X and Y position, I can also set it's direction when it collides with the terrain that blocks it. The only problem I have is that I can't think of a way to intelligently navigate my way around the map, so far I've been basing it around what direction the critter is facing when it collides with the terrain, and this is in no way a good way of moving around the map! I'm not a games programmer, and this is for a software assignment, so I have no clue on AI techniques. All I am after is a push in the right direction on how I could go about getting this critter to find it's way around any map given to me. Here's an image of the map and critters to give you an idea of what i'm talking about. Here's a link to an image of what the maps and critters look like. Map and Critter image I'm in no way looking for anyone to give me a full solution, just a push in the general direction on map navigation. Thanks in advance!

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  • How do I create a hyperlink in java?

    - by Justin984
    I'm going through the google app engine tutorials at https://developers.google.com/appengine/docs/java/gettingstarted/usingusers I'm very new to google app engine, java and web programming in general. So my question is, at the bottom of the page it says to add a link to allow the user to log out. So far I've got this: public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException { UserService userService = UserServiceFactory.getUserService(); User user = userService.getCurrentUser(); if(user != null){ resp.setContentType("text/plain"); resp.getWriter().println("Hello, " + user.getNickname()); String logoutLink = String.format("<a href=\"%s\">Click here to log out.</a>", userService.createLogoutURL(req.getRequestURI())); resp.getWriter().println(logoutLink); }else { resp.sendRedirect(userService.createLoginURL(req.getRequestURI())); } } However instead of a link, the full string is printed to the screen including the tags. When I look at the page source, I have no tags or any of the other stuff that goes with a webpage. I guess that makes sense considering I've done nothing to output any of that. Do I just do a bunch of resp.GetWriter().println() statements to output the rest of the webpage, or is there something else I don't know about? Thanks!

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  • Array of templated structs

    - by Jakub Mertlik
    I have structs templated by int derived from a Base struct. struct Base { int i; double d; }; template< int N > struct Derv : base { static const int mN = N; }; I need to make an array of Derv< N where N can vary for each struct in that array. I know C/C++ does not allow arrays of objects of different types, but is there a way around this? I was thinking of separating the type information somehow (hints like pointers to Base struct or usage of union spring to my mind, but with all of these I don't know how to store the type information of each array element for usage DURING COMPILE TIME). As you can see, the memory pattern of each Derv< N is the same. I need to access the type of each array element for template specialization later in my code. The general aim of this all is to have a compile-time dispatch mechanism without the need to do a runtime "type switch" somewhere in the code. Thank you.

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  • Unit testing that an event is raised in C#, using reflection

    - by Thomas
    I want to test that setting a certain property (or more generally, executing some code) raises a certain event on my object. In that respect my problem is similar to http://stackoverflow.com/questions/248989/unit-testing-that-an-event-is-raised-in-c, but I need a lot of these tests and I hate boilerplate. So I'm looking for a more general solution, using reflection. Ideally, I would like to do something like this: [TestMethod] public void TestWidth() { MyClass myObject = new MyClass(); AssertRaisesEvent(() => { myObject.Width = 42; }, myObject, "WidthChanged"); } For the implementation of the AssertRaisesEvent, I've come this far: private void AssertRaisesEvent(Action action, object obj, string eventName) { EventInfo eventInfo = obj.GetType().GetEvent(eventName); int raisedCount = 0; Action incrementer = () => { ++raisedCount; }; Delegate handler = /* what goes here? */; eventInfo.AddEventHandler(obj, handler); action.Invoke(); eventInfo.RemoveEventHandler(obj, handler); Assert.AreEqual(1, raisedCount); } As you can see, my problem lies in creating a Delegate of the appropriate type for this event. The delegate should do nothing except invoke incrementer. Because of all the syntactic syrup in C#, my notion of how delegates and events really work is a bit hazy. How to do this?

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  • Where is the Open Source alternative to WPF?

    - by Evan Plaice
    If we've learned anything from HTML/CSS it's that, declarative languages (like XML) work best to describe User Interfaces because: It's easy to build code preprocessors that can template the code effectively. The code is in a well defined well structured (ideally) format so it's easy to parse. The technology to effectively parse or crawl an XML based source file already exists. The UIs scripted code becomes much simpler and easier to understand. It simple enough that designers are able to design the interface themselves. Programmers suck at creating UIs so it should be made easy enough for designers. I recently took a look at the meat of a WPF application (ie. the XAML) and it looks surprisingly familiar to the declarative language style used in HTML. It's blindingly apparent to me that the current state of desktop UI development is largely fractionalized, otherwise there wouldn't be so much duplicated effort in the domain of user interfaces (IE. GTK, XUL, Qt, Winforms, WPF, etc). There are 45 GUI platforms for Python alone It's painfully obvious to me that there should be a general purpose, open source, standardized, platform independent, markup language for designing desktop GUIs. Much like what the W3C made HTML/CSS into. WPF, or more specifically XAML seems like a pretty likely step in the right direction. Why hasn't anyone in the Open Source community (AFAIK) even scratched the surface of this issue. Now that the 'browser wars' are over should we look forward to a future of 'desktop gui wars?' Note: This topic is relatively subjective in the attempt to be 'future-thinking.' I think that desktop GUI development in its current state sucks ((really)hard) and, even though WPF is still in it's infancy, it presents a likely solution to the problem. Has no one in the OS community looked into developing something similar because they don't see the value, or because it's not worth the effort?

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  • Plotting an Arc in Discrete Steps

    - by phobos51594
    Good afternoon, Background My question relates to the plotting of an arbitrary arc in space using discrete steps. It is unique, however, in that I am not drawing to a canvas in the typical sense. The firmware I am designing is for a gcode interpreter for a CNC mill that will translate commands into stepper motor movements. Now, I have already found a similar question on this very site, but the methodology suggested (Bresenham's Algorithm) appears to be incompatable for moving an object in space, as it only relies on the calculation of one octant of a circle which is then mirrored about the remaining axes of symmetry. Furthermore, the prescribed method of calculation an arc between two arbitrary angles relies on trigonometry (I am implementing on a microcontroller and would like to avoid costly trig functions, if possible) and simply not taking the steps that are out of the range. Finally, the algorithm only is designed to work in one rotational direction (e.g. counterclockwise). Question So, on to the actual question: Does anyone know of a general-purpose algorithm that can be used to "draw" an arbitrary arc in discrete steps while still giving respect to angular direction (CW / CCW)? The final implementation will be done in C, but the language for the purpose of the question is irrelevant. Thank you in advance. References S.O post on drawing a simple circle using Bresenham's Algorithm: "Drawing" an arc in discrete x-y steps Wiki page describing Bresenham's Algorithm for a circle http://en.wikipedia.org/wiki/Midpoint_circle_algorithm Gcode instructions to be implemented (see. G2 and G3) http://linuxcnc.org/docs/html/gcode.html

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  • Should I write more SQL to be more efficient, or less SQL to be less buggy?

    - by RenderIn
    I've been writing a lot of one-off SQL queries to return exactly what a certain page needs and no more. I could reuse existing queries and issue a number of SQL requests linear to the number of records on the page. As an example, I have a query to return People and a query to return Job Details for a person. To return a list of people with their job details I could query once for people and then once for each person to retrieve their job details. I've found that in most cases that solution returns things in a reasonable amount of time, but I don't know how well it will scale in my environment. Instead I've been writing queries to join people + job details, or people + salary history, etc. I'm looking at my models and I see how I could shave off maybe 30% of my code if I were to re-use existing queries. This is a big temptation. Is it a bad thing to go for reuse over efficiency in general or does it all come down to the specific situation? Should I first do it the easy way and then optimize later, or is it best to get the code knocked out while everything is fresh in my mind? Thoughts, experiences?

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  • SQLite dataypes lengths?

    - by XF
    I'm completely new to SQLite (actually 5 minutes ago), but I do know somewhat the Oracle and MySql backends. The question: I'm trying to know the lengths of each of the datatypes supported by SQLite, such as the differences between a bigint and a smallint. I've searched across the SQLite documentation (only talks about affinity, only matters it?), SO threads, google... and found nothing. My guess: I've just slightly revised the SQL92 specifications, which talk about datatypes and its relations but not about its lengths, which is quite obvious I assume. Yet I've come accross the Oracle and MySql datatypes specs, and the specified lengths are mostly identical for integers at least. Should I assume SQLite is using the same lengths? Aside question: Have I missed something about the SQLite docs? Or have I missed something about SQL in general? Asking this because I can't really understand why the SQLite docs don't specify something as basic as the datatypes lengths. It just doesn't make sense to me! Although I'm sure there is a simple command to discover the lengths.. but why not writing them to the docs? Thank you!

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  • Which source control paradigm and solution to embed in a custom editor application?

    - by Greg Harman
    I am building an application that manages a number of custom objects, which may be edited concurrently by multiple users (using different instances of the application). These objects have an underlying serialized representation, and my plan is to persist them (through my application UI) in an external source control system. Of course this implies that my application can check the current version of an object for updates, a merging interface for each object, etc. My question is what source control paradigm(s) and specific solution(s) to support and why. The way I (perhaps naively) see the source control world is three general paradigms: Single-repository, locked access (MS SourceSafe) Single-repository, concurrent access (CVS/SVN) Distributed (Mercurial, Git) I haven't heard of anyone using #1 for quite a number of years, so I am planning to disregard this case altogether (unless I get a compelling argument otherwise). However, I'm at a loss as to whether to support #2 or #3, and which specific implementations. I'm concerned that the use paradigms are subtly different enough that I can't adequately capture basic operations in a single UI. The last bit of information I should convey is that this application is intended to be deployed in a commercial setting, where a source control system may already be in use. I would prefer not to support more than one solution unless it's really a deal-breaker, so wide adoption in a corporate setting is a plus.

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  • Cannot clear the form after Submit using the Validation plugin in jQuery

    - by novellino
    Hello, I an quite new to jQuery and I have a problem while trying to create a form. I am using the Validation plugin for validate the email (one the form's field). When I click the Submit button I want to call my own function because I want to save the data in an XML file. This is my button: (as I understood the plugin uses "submit" for understand the button) <input type="submit" name="submit" class="submit" id="submit_btn" value="Send"/> and here is the script for the validation: <script type="text/javascript"> $(document).ready(function() { //this is my form $("#contactForm").validate(); /*save the valid data in the xml*/ $(".submit").click(function() { var email = $("input#email").val(); var subject = $("input#subject").val(); var message = $("textarea#message").val(); if (email == "" || !$("#contactForm").valid()) { return false; } var dataString = 'email='+ email + '&subject=' + subject + '&message=' + message; //alert("DATA: " +dataString); $.ajax({ type: "POST", url: "SaveData.jsp", data: dataString, success: function(data){} }); return false; }); }); </script> In general it works ok but I have two basic problems. When I click the button in the beginning having all the form empty, I get no message for the field required. Also when the data are valid and I am doing the submit, the form does not become clear after the submit. If I deleted this script code, these actions are working properly but I can not save the data! Does anyone know what is wrong? Thanks a lot!

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  • jQuery AJAX Loading Page Content Only After I Press Shift Key

    - by Cosmin
    My ajax + jquery loading page only after holding shift key and duplicate new empty window. If I press the loading button nothing hapen, only after I press shift key I get to load the page correctly... this is my ajax script: $(document).ready(function () { $(".getUsersA").click(function () { $.ajax({ beforeSend: function () { $(".gridD").html(spinner) }, url: 'lib/some_url.php', type: 'POST', data: ({ data1:'2013-09-01' }), success: function (results) {$(".gridD").html(results);} }); }); }); I have a second js file with just this line of code for spinner var spinner = "<img src='images/spinner.gif' border='0'>"; html code: <html> <head> <title>Title</title> <script type="text/javascript" src="js/jquery-1.10.2.js"></script> <script type="text/javascript" src="js/ajax.js"></script> <script type="text/javascript" src="js/general.js"></script> </head> <body> <h1>Putting it all tugether ... with jQuery</h1> <div class="thedivD"><a href="" class="buttonA getUsersA">Get Users</a></div> <h3>jQuery results</h3> <div class="gridD"></div> </body> </html>

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  • Content Management Systems for Adaptive Content [closed]

    - by andrewap
    Content management systems (CMS) allow us to easily maintain blogs, news sites, general websites, and so on. Many of them are designed to manage pages of content, and provide tools to organize and customize how that content is displayed on the web. However, as explained by Mark Boulton in his Adaptive Content Management article, and by Karen McGrane in her talk on Adapting Ourselves to Adaptive Content, we are increasingly delivering content not just to the web, but also to other platforms and channels. We need tools to manage pieces of content with meaningful metadata attached. Create once, publish everywhere. The main idea is to store content cleanly, without intertwining it with presentation markup specific to the web. Because pieces of content is compartmentalized semantically, it can easily adapt to fit in different platforms and channels. Hence, it's called adaptive content. Let's look at a quick example to compare: Say I manage news articles and events. To create a news article, I would tell the CMS the type of content I'm creating, and be asked to fill in a form with individual fields tailored to news articles (e.g. headline, subtitle, full text, short snippet, and images). — i.e. pieces of content With a traditional web publishing tool, I would probably have had to create a new page under News, and then type in and format the news article in a blank WYSIWYG text editor. — i.e. pages of content As you can see, the first design allows me to individually specify content in its smallest semantic unit. When I want to display or consume it, the system can easily provide the pieces I need. So here's my question: Is there a CMS that is designed specifically with adaptive content in mind, and that is decoupled with the presentation layer? Note: This is not a discussion about the best CMS, or which CMS I should use. I am asking whether a very specific type of tool — CMS designed for adaptive content — exists for developers to use.

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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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  • Is Git ready to be recommended to my boss?

    - by Mike Weller
    I want to recomment Git to my boss as a new source control system, since we're stuck in the 90s with VSS (ouch), but are the tools and 3rd party support good enough yet? Specifically I'm talking about GUI front-ends similar to TortoiseSVN, decent visual diff/merge support, as well as stuff like email commit notifications and general support from 3rd parties like IDEs and build systems. Even though this will be used by programmers, we really need this kind of stuff in our team. I don't want to leave everyone stuck with a new tool, and even a new source control paradigm (distributed), with nothing but a command-line app and some online tutorials. This would be a step backwards. So what do you think... is Git ready? What decent tools exist for Git and what third party development apps support it? EDIT: My original question was pretty vague so I'm updating it to specifically ask for a list of available tools and 3rd party support for Git. Maybe we can get a community wiki post with a list of stuff. I also do not consider 'use subversion' to be an adequate answer. There are other reasons to use a distributed source control system other than offline editing - private and cheap branches being one of them.

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  • Finding the Column Index for a Specific Value

    - by Btibert3
    Hi All, I am having a brain cramp. Below is a toy dataset: df <- data.frame( id = 1:6, v1 = c("a", "a", "c", NA, "g", "h"), v2 = c("z", "y", "a", NA, "a", "g"), stringsAsFactors=F) I have a specific value that I want to find across a set of defined columns and I want to identify the position it is located in. The fields I am searching are characters and the trick is that the value I am looking for might not exist. In addition, null strings are also present in the dataset. Assuming I knew how to do this, the variable position indicates the values I would like returned. > df id v1 v2 position 1 1 a z 1 2 2 a y 1 3 3 c a 2 4 4 <NA> <NA> 99 5 5 g a 2 6 6 h g 99 The general rule is that I want to find the position of value "a", and if it is not located or if v1 is missing, then I want 99 returned. In this instance, I am searching across v1 and v2, but in reality, I have 10 different variables. It is also worth noting that the value I am searching for can only exist once across the 10 variables. What is the best way to generate this recode? Many thanks in advance.

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  • Mixing JSP/HTML any new features or suggestions

    - by Maglebolia
    Hi all, I have a Web-Application, which is mainly JSP (file extension) and is including some HTML. It seems to me that the "general" way is "old" and not always well red by some IDE like Eclipse: Is there no other way to include jsp expression with "<% ... %". There is no need for a framework to resolve this, since we only have like 60 pages. I run through examples and see that we can seperate the code with blockquotes "< script < /script ". I'm really wondering which is the better method for understanding and easier reading of the code. Any formatting, syntax coloring, plugin or new code style suggestions would help. Here an example <%} %> <%if(condition) { %> <tr> <td class="label"><%=method()%></td> <td class="text"><%=method()%></td> </tr> <%} %> <tr>

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  • How to best future proof my application that needs to connect to Outlook?

    - by Troy
    I have a contact management application written in Delphi which has a “Sync with Outlook” feature that I developed 10 years ago. Now, I’m going back to add some features and fix some bugs. This sync feature uses the Outlook object model to get started, but it has an optional mode called “Use MAPI Enhancements” where it uses pure MAPI to speed up how it looks for changes, and it allows notes to be synced w/ RTF instead of just plain text. I'm wondering if supporting two parallel paths of execution is a good idea or not. If I went with all MAPI, I believe I'd avoid some security prompts, and I'd avoid situations where anti-virus has "script-blocking" features which block my app from connecting to Outlook. But I believe that on the down side, my 32-bit app would not be able to to connect with 64-bit Outlook 2010 using MAPI. And I wonder about the future of MAPI in general. If I stick with the Outlook object model, will my 32-bit app be able to connect to the Outlook object model (since it's out of process COM)? If so, this is a compelling reason to keep my Outlook object model execution path in place. But if not, and if my app needs to be compiled for x64, then why not just go with pure MAPI?

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  • Python, Ruby, and C#: Use cases?

    - by thaorius
    Hi everyone. For as long as I can remember, I've always had a "favorite" language, which I use for most projects, until, for some particular reason, there is no way/point on using it for project XYZ. At that point, I find myself rusty (and sometimes outdated) on other languages+libraries+toolchains. So I decided, I would just use some languages/libs/tools for some things, and some for other, effectively keeping them fresh (there would obviously be exceptions, I'm not looking for an arbitrary rule set, but some guidelines). I wanted an opinion on what would be your standard use cases (new projects) for Python, Ruby, and C# (Mono). At the moment, I have time like this:Languages: C#: Mid-Large Sized Projects (mainly server-side daemons) High Performance (I hardly ever need C's performance, but Python just doesn't cut it) Relatively Low Footprint (vs the JVM, for example) Ruby: Web Applications Python: General Use Scripts (automation, system config, etc) Small-Mid Sized Projects Prototyping Web Applications About Ruby, I have no idea what to use it for that I can't use Python for (specially considering Python is more easily found installed by default). And I like both languages (though I'm really new to Ruby), which makes things even worse. As for C#, I have not used a Windows powered computer in a few years, I don't make things for Windows computers, and I don't mind waiting for Mono to implement some new features. That being said, I haven't found many people on the internet using it for server-sided *nix programming (not web related). I would appreciate some insight on this too. Thanks for your time.

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  • Implementing a 1 to many relationship with SQLite

    - by Patrick
    I have the following schema implemented successfully in my application. The application connects desk unit channels to IO unit channels. The DeskUnits and IOUnits tables are basically just a list of desk/IO units and the number of channels on each. For example a desk could be 4 or 12 channel. CREATE TABLE DeskUnits (Name TEXT, NumChannels NUMERIC); CREATE TABLE IOUnits (Name TEXT, NumChannels NUMERIC); CREATE TABLE RoutingTable (DeskUnitName TEXT, DeskUnitChannel NUMERIC, IOUnitName TEXT, IOUnitChannel NUMERIC); The RoutingTable 'table' then connects each DeskUnit channel to an IOUnit channel. For example the DeskUnit called "Desk1" channel 1 may route to IOunit name "IOUnit1" channel 2, etc. So far I hope this is pretty straightforward and understandable. The problem is, however, this is a strictly 1 to 1 relationship. Any DeskUnit channel can route to only 1 IOUnit channel. Now, I need to implement a 1 to many relationship. Where any DeskUnit channel can connect to multiple IOUnit channels. I realise I may have to rearrange the tables completely, but I am not sure the best way to go about this. I am fairly new to SQLite and databases in general so any help would be appreciated. Thanks Patrick

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  • Where should I store shared resources between LocalSystem and regular user with UAC?

    - by rwired
    My application consists of two parts: A Windows Service running under the LocalSystem account and a client process running under the currently logged in regular user. I need to deploy the application across Windows versions from XP up to Win7. The client will retrieve files from the web and collect user data from the user. The service will construct files and data of it's own which the client needs to read. I'm trying to figure out the best place (registry or filesystem, or mix) to store all this. One file the client or service needs to be able to retrieve from the net is an update_patch executable which needs to run whenever an upgrade is available. I need to be sure the initial installer SETUP.EXE, and also the update_patch can figure out this ideal location and set a RegKey to be read later by both client and server telling them the magic location (The SETUP.EXE will run with elevated privileges since it needs to install the service) On my Win7 test system the service %APPDATA% points to: C:\Windows\system32\config\systemprofile\AppData\Roaming and the %APPDATA% of the client points to: C:\Users\(username)\AppData\Roaming Interestingly Google Chrome stores everything (App and Data) in C:\Users\(username)\AppData\Local\Google\Chrome Chrome runs pretty much in exactly the way I want my suite to run (able to silently update itself in the background) What I'm trying to avoid is nasty popups warning the user that the app wants to modify the system, and I want to avoid problems when VirtualStore doesn't exist because the user is running XP/2000/2003 or has UAC turned off. My target audience are non-tech-savvy general Windows users.

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  • Clearly defined Rails routing problem - undefined method for Nil:NilClass

    - by sscirrus
    Guys and girls, I have been working on this problem for a while but still no joy. This is my second question within this general area, because the last question was getting too long and this is now more well-defined. Summary of the Problem: I am loading a page for my customers and I get error: undefined method 'name' for Nil:NilClass My Code #Link on views/users/show.html.erb: <%= link_to "Customer Account", :action => "home", :controller => "customers", :id => @user.user_type_id %> #Regular Route: map.connect 'customers/home/:id', :controller => 'customers', :action => 'home' #Rake Routes, first entry: /customers/home/:id :controller=>:"customers", :action=>"home" #Customers Controller: def home render :layout => 'home' @customer = Customer.find(params[:id]) @user = @current_user_session.user flash[:error] = "Customer not found" and return unless @customer @jobs = @customer.jobs end #views/customers/home.html.erb: <%= @customer.name %> I have absolutely no idea why this seemingly clear sequence of events is resulting in a NilClass. Search the console for Customer.find(2) returns the correct customer. What is this noob missing? Thank you very much.

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