Search Results

Search found 11897 results on 476 pages for 'dean rather'.

Page 375/476 | < Previous Page | 371 372 373 374 375 376 377 378 379 380 381 382  | Next Page >

  • Use of Syntactic Sugar / Built in Functionality

    - by Kyle Rozendo
    I was busy looking deeper into things like multi-threading and deadlocking etc. The book is aimed at both pseudo-code and C code and I was busy looking at implementations for things such as Mutex locks and Monitors. This brought to mind the following; in C# and in fact .NET we have a lot of syntactic sugar for doing things. For instance (.NET 3.5): lock(obj) { body } Is identical to: var temp = obj; Monitor.Enter(temp); try { body } finally { Monitor.Exit(temp); } There are other examples of course, such as the using() {} construct etc. My question is when is it more applicable to "go it alone" and literally code things oneself than to use the "syntactic sugar" in the language? Should one ever use their own ways rather than those of people who are more experienced in the language you're coding in? I recall having to not use a Process object in a using block to help with some multi-threaded issues and infinite looping before. I still feel dirty for not having the using construct in there. Thanks, Kyle

    Read the article

  • Loading page all content and scripts inside another

    - by Robin I Knight
    If you go to this page on our website: http://www.divethegap.com/scuba-diving-programmes-dive-the-gap/dahab-divemaster-training.html The buttons at the bottom that say 'Beginner' 'Open Water Diver' etc.... They take you to another page where you have a series of options and can book. We would like it so that rather than have to navigate to another page it loaded those options and all the scripts that make the calculations in a div on the first page. Depending on which button you press depends on which page it would load inside the div. IFrame does not work as it does not dynamically resize when the collapsible panels are opened. AJAX script at dynamic drive. http://www.dynamicdrive.com/dynamicindex17/ajaxcontent.htm does not work as none of the collapsible panels work, nor does the calculation script. How can this be done. To sum it up it would be like turning the buttons at the bottom of the page into tabs that would display the content from the pages those buttons currently link through to. Is this possible.

    Read the article

  • how do simple SQLAlchemy relationships work?

    - by Carson Myers
    I'm no database expert -- I just know the basics, really. I've picked up SQLAlchemy for a small project, and I'm using the declarative base configuration rather than the "normal" way. This way seems a lot simpler. However, while setting up my database schema, I realized I don't understand some database relationship concepts. If I had a many-to-one relationship before, for example, articles by authors (where each article could be written by only a single author), I would put an author_id field in my articles column. But SQLAlchemy has this ForeignKey object, and a relationship function with a backref kwarg, and I have no idea what any of it MEANS. I'm scared to find out what a many-to-many relationship with an intermediate table looks like (when I need additional data about each relationship). Can someone demystify this for me? Right now I'm setting up to allow openID auth for my application. So I've got this: from __init__ import Base from sqlalchemy.schema import Column from sqlalchemy.types import Integer, String class Users(Base): __tablename__ = 'users' id = Column(Integer, primary_key=True) username = Column(String, unique=True) email = Column(String) password = Column(String) salt = Column(String) class OpenID(Base): __tablename__ = 'openid' url = Column(String, primary_key=True) user_id = #? I think the ? should be replaced by Column(Integer, ForeignKey('users.id')), but I'm not sure -- and do I need to put openids = relationship("OpenID", backref="users") in the Users class? Why? What does it do? What is a backref?

    Read the article

  • Different EF Property DataType than Storage Layer Possible?

    - by dj_kyron
    Hi, I am putting together a WCF Data Service for PatientEntities using Entity Framework. My solution needs to address these requirements: Property DateOfBirth of entity Patient is stored in SQL Server as string. It would be ideal if the entity class did not also use the "string" type but rather a DateTime type. (I would expect this to be possible since we're abstracting away from the storage layer). Where could a conversion mechanism be put in place that would convert to and from DateTime/string so that the entity and SQL Server are in sync?. I cannot change the storage layer's structure, so I have to work around it. WCF Data Services (Read-only, so no need for saving changes) need to be used since clients will be able to use LINQ expressions to consume the service. They can generate results based on any given query scenario they need and not be constrained by a single method such as GetPatient(int ID). I've tried to use DTOs, but run into problem of mapping the ObjectContext to a DTO, I don't think that is theoretically possible...or too complicated if it is. I've tried to use Self Tracking Entities but they require the metadata from the .edmx file if I'm correct, and this isn't allowing a different property data type. I also want to add customizations to my Entity getter methods so that a property "MRN" of type "string" needs to have .Replace("MR~", string.Empty) performed before it is returned. I can add this to the getter methods but the problem with that is Entity Framework will overwrite that next time it refreshes the entity classes. Is there a permanent place I can put these? Should I use POCO instead? How would that work with WCF Data Services? Where would the service grab the metadata?

    Read the article

  • Suggestions for a Cron like scheduler in Python?

    - by jamesh
    I'm looking for a library in Python which will provide at and cron like functionality. I'd quite like have a pure Python solution, rather than relying on tools installed on the box; this way I run on machines with no cron. For those unfamiliar with cron: you can schedule tasks based upon an expression like: 0 2 * * 7 /usr/bin/run-backup # run the backups at 0200 on Every Sunday 0 9-17/2 * * 1-5 /usr/bin/purge-temps # run the purge temps command, every 2 hours between 9am and 5pm on Mondays to Fridays. The cron time expression syntax is less important, but I would like to have something with this sort of flexibility. If there isn't something that does this for me out-the-box, any suggestions for the building blocks to make something like this would be gratefully received. Edit I'm not interested in launching processes, just "jobs" also written in Python - python functions. By necessity I think this would be a different thread, but not in a different process. To this end, I'm looking for the expressivity of the cron time expression, but in Python. Cron has been around for years, but I'm trying to be as portable as possible. I cannot rely on its presence.

    Read the article

  • Java/XML: Good "Stream-based" Alternative to JAXB?

    - by Jan
    Hello Experts, JAXB makes working with XML so much easier, but I have currently a big problem, that the documents I have to process are too large for an in memory unmarshalling that JAXB does. The data can be up to 4GB per document. The datastructure I will have to process is very simple and flat: With a root element and millions of “elements”… <root> <element> <sub>foo</sub> </element> <element> <sub>foo</sub> </element> </root> May questions are: Does JAXB maybe somehow support unmarshalling in a “streambased” way, that does not require to build the whole objecttree in memory but rather gives me some kind of “Iterator” to the elements, element by element? (Maybe I just missed that somehow…) If not what are your proposals for an good alternative with a a. “flat learningcurve, ideally very similar to JAXB b. AND VERY IMPORTANT: Ideally with the possibility / tool for the generation of the unarshaller code from an XSD file OR annotated Java Class 3.(I have searched SO and those to library that ended up on my “watchlist” (without comparing them closer) were Apache XML Beans and Xstream… What other libraries are maybe even better for the purpose and what are the disadvantages, adavangaes… Thank you very much!!! Jan

    Read the article

  • Selecting a whole database over an individual table to output to file

    - by Daniel Wrigley
    :::::::: EDIT :::::::: New code for people to have a look at, one question I have with this is where do I set were the *.gz file is saved? $backupFile = $dbname . date("Y-m-d-H-i-s") . '.gz'; $command = "mysqldump --opt -h $dbhost -u $dbuser -p $dbpass $dbname | gzip > $backupFile"; system($command); Also why the hell can you not reply yo your own post with answering it? :( :::::::: EDIT :::::::: Ok Im having trouble finding out how to select a full database for backup as an *.sql file rather than only an individual table. On the localhost I have several databases with one named "foo" and it is that which I want to backup and not any of the individual tables inside the database "foo". The code to connect to the database; //Database Information $dbhost = "localhost"; $dbname = "foo"; $dbuser = "bar"; $dbpass = "rulz"; //Connect to database mysql_connect ($dbhost, $dbuser, $dbpass) or die("Could not connect: ".mysql_error()); mysql_select_db($dbname) or die(mysql_error()); The code to backup the database; // Grab the time to know when this post was submitted $time = date('Y-m-d-H-i-s'); $tableName = 'foo'; $backupFile = '/sql/backup/'. $time .'.sql'; $query = "SELECT * INTO OUTFILE '". $backupFile ."' FROM ". $tableName .""; $result = mysql_query($query)or die("Database query died: " . mysql_error()); My brain is hurting near to the end of the day so no doubts i've missed something out very obvious. Thanks in advance to anyone helping me out.

    Read the article

  • how would you like computer science classes to be taught?

    - by aaa
    hello I am a graduate student now, and hopefully someday I will teach. my interests are C++, Python, embedded languages, and scientific computing. Meanwhile I daydream about how I would teach. I was not quite happy with my undergraduate university as I found many computer science classes lacking. so I would like to ask you, if you were a student, how would you like your computer science classes to be taught? I understand it is a very subjective question, but nevertheless I think it's important to know what people want. Some specific points I am interested in: should computer languages be taught explicitly, or should students be required to pick up language on their own? what is better for learning, tests, projects, some sort of take-home exam? how do you think classtime should be used? theory, introduction, explanations, etc.? do you think the group projects are important? how much about computer architecture do you want to learn in computer science class, not necessarily assembler class. should particular operating system/editor be mandated or encouraged? Thanks thank you for your comments. Question has been closed because it is a discussion question rather than Q&A. If you know appropriate website for discussions of such sort with low noise ratio, please let me know.

    Read the article

  • How much effort do you have to put in to get gains from using SSE?

    - by John
    Case One Say you have a little class: class Point3D { private: float x,y,z; public: operator+=() ...etc }; Point3D &Point3D::operator+=(Point3D &other) { this->x += other.x; this->y += other.y; this->z += other.z; } A naive use of SSE would simply replace these function bodies with using a few intrinsics. But would we expect this to make much difference? MMX used to involve costly state cahnges IIRC, does SSE or are they just like other instructions? And even if there's no direct "use SSE" overhead, would moving the values into SSE registers and back out again really make it any faster? Case Two Instead, you're working with a less OO-based code base. Rather than an array/vector of Point3D objects, you simply have a big array of floats: float coordinateData[NUM_POINTS*3]; void add(int i,int j) //yes it's unsafe, no overlap check... example only { for (int x=0;x<3;++x) { coordinateData[i*3+x] += coordinateData[j*3+x]; } } What about use of SSE here? Any better? In conclusion Is trying to optimise single vector operations using SSE actually worthwhile, or is it really only valuable when doing bulk operations?

    Read the article

  • MSI Installer start auto-repair when service starts

    - by Josh Clark
    I have a WiX based MSI that installs a service and some shortcuts (and lots of other files that don't). The shortcut is created as described in the WiX docs with a registry key under HKCU as the key file. This is an all users install, but to get past ICE38, this registry key has to be under the current user. When the service starts (it runs under the SYSTEM account) it notices that that registry key isn't valid (at least of that user) and runs the install again to "repair". In the Event Log I get MsiInstaller Events 1001 and 1004 showing that "The resource 'HKEY_CURRENT_USER\SOFTWARE\MyInstaller\Foo' does not exist." This isn't surprising since the SYSTEM user wouldn't have this key. I turned on system wide MSI logging and the auto-repair created its log file in the C:\Windows\Temp folder rather than a specific user's TEMP folder which seems to imply the current user was SYSTEM (plus the log file shows the "Calling process" to be my service). Is there something I can do to disable the auto-repair functionality? Am I doing something wrong or breaking some MSI rule? Any hints on where to look next?

    Read the article

  • PendingIntents in Notifications

    - by Mariano Kamp
    I would like to show a notification that displays the progress of an ongoing operation. That works well for me. But at the same time the remote view should contain cancel button to stop the ongoing operation. The usual content intent should still do something else, i.e. not cancel the ongoing operation. It seems though that I can only have one intent. I have to specify a contentIntent that is launched when clicking on the notification: If I don't specify that I get something along those lines: E/ActivityManager( 62): Activity Manager Crash E/ActivityManager( 62): java.lang.IllegalArgumentException: contentIntent required ... For the "cancel" button I set another intent: Intent cancelSyncIntent = new Intent("com.xyz.CANCEL_SYNC"); contentView.setOnClickPendingIntent(R.id.cancel_sync, PendingIntent.getBroadcast(context, 0, cancelSyncIntent, 0)); But this never works. I always get the content intent when the button is clicked. It looks like I cannot use buttons in remote views of notifications?! I could probably display a text: "<< Press to cancel operation ", but that seems rather heavy handed.

    Read the article

  • Null reference exceptions in .net

    - by Carlo
    Hello, we're having this big problem with our application. It's a rather large application with several modules, and thousands and thousands lines of code. A lot of parts of the application are designed to exist only with a reference to another object, for example a Person object can never exists without a House object, so if you at any point in the app say: bool check = App.Person.House == null; check should always be false (by design), so, to keep using that example, while creating modules, testing, debugging, App.Person.House is never null, but once we shipped the application to our client, they started getting a bunch of NullReferenceException with the objects that by design, should never have a null reference. They tell us the bug, we try to reproduce it here, but 90% of the times we can't, because here it works fine. The app is being developed with C# and WPF, and by design, it only runs on Windows XP SP 3, and the .net framework v3.5, so we KNOW the user has the same operative system, service pack, and .net framework version as we do here, but they still get this weird NullReferenceExceptions that we can't reproduce. So, I'm just wondering if anyone has seen this before and how you fixed it, we have the app running here at least 8 hours a day in 5 different computers, and we never see those exceptions, this only happens to the client for some reason. ANY thought, any clue, any solution that could get us closer to fixing this problem will be greatly appreciated. Thanks!

    Read the article

  • How can I provide users with the functionality of the DBUnit DatabaseOperation methods from a web in

    - by reckoner
    I am currently updating a java-based web application which allows database developers to create stored procedure regression test suites for database testing. Currently, for test setup, execution and clean-up stages, the user is provided with text boxes where they are able to enter SQL code which is executed by the isql command. I would like to extend the application to use DB Unit’s DatabaseOperation methods to provide more ways to setup the state of the database than just SQL statements. The main reason for using Db Unit rather than just SQL statements is to be able to create and store xml and xls DataSets on a server where they can be associated with their test cases and used for data setup. My question is: How can I provide users with the functionality of the DBUnit DatabaseOperation methods from a web interface? I have considered: Creating a simple programming language and a parser to read some simple syntax involving the DB Unit method names which accept a parameter being the file location to an xml or xls DataSet. I was thinking of allowing the user to register the files they need with the web app which would catalogue them and provide each file with an identifier which could passed as a parameter to the methods in this simple programming language. Creating an XML DTD which provides the user with the ability to specify operations and parameters. If I went this approach, how can I execute the methods and their parameters that I parse from the XML document? Creating a table in the database which stores the method and a FK relation to a catalogued DataSet file, however I don’t think this would be good solution due to the fact that data entry would be tedious. Thanks for your help.

    Read the article

  • Choosing between .NET Service Bus Queues vs Azure Queue Service

    - by ChrisV
    Just a quick question regarding an Azure application. If I have a number of Web and Worker roles that need to communicate, documentation says to use the Azure Queue Service. However, I've just read that the new .NET Service Bus now also offers queues. These look to be more powerful as they appear to offer a much more detailed API. Whilst the .NSB looks more interesting it has a couple of issues that make me wary of using it in distributed application. (for example, Queue Expiration... if I cannot guarantee that a queue will be renewed on time I may lose it all!). Has anyone had any experience using either of these two technologies and could give any advice on when to choose one over the other. I suspect that whilst the service bus looks more powerful, as my use case is really just enabling Web/Worker roles to communicate between each other, that the Azure Queue Service is what I'm after. But I'm just really looking for confirmation of that before progamming myself in to a corner :-) Thanks in advance. UPDATE Have read up about the two systems over the break. It defo looks like .NET service bus is more specifically designed for integrating systems rather than providing a general purpose reliable messaging system. Azure Queues are distributed and so reliable and scalable in a way that .NSB queues are not and so more suitable for code hosted within Azure itself. Thanks for the responses.

    Read the article

  • Assigning console.log to another object (Safari issue)

    - by Trevor Burnham
    I wanted to keep my logging statements as short as possible while preventing console from being accessed when it doesn't exist; I came up with the following solution: var _ = {}; if (console) { _.log = console.debug; } else { _.log = function() { } } To me, this seems quite elegant, and it works great in Firefox 3.6 (including preserving the line numbers that make console.debug more useful than console.log). But it doesn't work in Safari 4. (Haven't tested in other browsers yet.) If I follow the above with console.debug('A') _.log('B'); the first statement works fine in both browsers, but the second generates a "TypeError: Type Error" in Safari. Is this just a difference between how Firebug and the Safari Web Developer Tools implement console? If so, it is VERY annoying on Apple's part. (I get the same results in both browsers if I bind the console function to a prototype and then instantiate, rather than binding it directly to the object.) I could, of course, just call console.debug from an anonymous function assigned to _.log, but then I'd lose my line numbers. Any other ideas?

    Read the article

  • Using a php://memory wrapper causes errors...

    - by HorusKol
    I'm trying to extend the PHP mailer class from Worx by adding a method which allows me to add attachments using string data rather than path to the file. I came up with something like this: public function addAttachmentString($string, $name='', $encoding = 'base64', $type = 'application/octet-stream') { $path = 'php://memory/' . md5(microtime()); $file = fopen($path, 'w'); fwrite($file, $string); fclose($file); $this->AddAttachment($path, $name, $encoding, $type); } However, all I get is a PHP warning: PHP Warning: fopen() [<a href='function.fopen'>function.fopen</a>]: Invalid php:// URL specified There aren't any decent examples with the original documentation, but I've found a couple around the internet (including one here on SO), and my usage appears correct according to them. Has anyone had any success with using this? My alternative is to create a temporary file and clean up - but that will mean having to write to disc, and this function will be used as part of a large batch process and I want to avoid slow disc operations (old server) where possible. This is only a short file but has different information for each person the script emails.

    Read the article

  • High Runtime for Dictionary.Add for a large amount of items

    - by aaginor
    Hi folks, I have a C#-Application that stores data from a TextFile in a Dictionary-Object. The amount of data to be stored can be rather large, so it takes a lot of time inserting the entries. With many items in the Dictionary it gets even worse, because of the resizing of internal array, that stores the data for the Dictionary. So I initialized the Dictionary with the amount of items that will be added, but this has no impact on speed. Here is my function: private Dictionary<IdPair, Edge> AddEdgesToExistingNodes(HashSet<NodeConnection> connections) { Dictionary<IdPair, Edge> resultSet = new Dictionary<IdPair, Edge>(connections.Count); foreach (NodeConnection con in connections) { ... resultSet.Add(nodeIdPair, newEdge); } return resultSet; } In my tests, I insert ~300k items. I checked the running time with ANTS Performance Profiler and found, that the Average time for resultSet.Add(...) doesn't change when I initialize the Dictionary with the needed size. It is the same as when I initialize the Dictionary with new Dictionary(); (about 0.256 ms on average for each Add). This is definitely caused by the amount of data in the Dictionary (ALTHOUGH I initialized it with the desired size). For the first 20k items, the average time for Add is 0.03 ms for each item. Any idea, how to make the add-operation faster? Thanks in advance, Frank

    Read the article

  • Can a C# method chain be "too long"?

    - by ccornet
    Not in terms of readability, naturally, since you can always arrange the separate methods into separate lines. Rather, is it dangerous, for any reason, to chain an excessively large number of methods together? I use method chaining primarily to save space on declaring individual one-use variables, and traditionally using return methods instead of methods that modify the caller. Except for string methods, those I kinda chain mercilessly. In any case, I worry sometimes about the impact of using exceptionally long method chains all in one line. Let's say I need to update the value of one item based on someone's username. Unfortunately, the shortest method to retrieve the correct user looks something like the following. SPWeb web = GetWorkflowWeb(); SPList list2 = web.Lists["Wars"]; SPListItem item2 = list2.GetItemById(3); SPListItem item3 = item2.GetItemFromLookup("Armies", "Allied Army"); SPUser user2 = item2.GetSPUser("Commander"); SPUser user3 = user2.GetAssociate("Spouse"); string username2 = user3.Name; item1["Contact"] = username2; Everything with a 2 or 3 lasts for only one call, so I might condense it as the following (which also lets me get rid of a would-be-superfluous 1): SPWeb web = GetWorkflowWeb(); item["Contact"] = web.Lists["Armies"] .GetItemById(3) .GetItemFromLookup("Armies", "Allied Army") .GetSPUser("Commander") .GetAssociate("Spouse") .Name; Admittedly, it looks a lot longer when it is all in one line and when you have int.Parse(ddlArmy.SelectedValue.CutBefore(";#", false)) instead of 3. Nevertheless, this is one of the average lengths of these chains, and I can easily foresee some of exceptionally longer counts. Excluding readability, is there anything I should be worried about for these 10+ method chains? Or is there no harm in using really really long method chains?

    Read the article

  • How do I get a ComboBox SelectionChanged event to fire from a nested ListBoxItem?

    - by Stephen McCusker
    This is a rather complex problem that has me really confused right now. Any help would be greatly appreciated. The Setup: ListBox of Type A UserControls -ListBoxItem of Type A UserControl --ListBox of Type B UserControls ---ListBoxItem of Type B UserControl ----ListBox of Type C UserControls -----ListBoxItem of Type C UserControl (contains the ComboBox) In other words, the Type A control has a ListBox of Type B controls that has a ListBox of Type C controls. All of the controls are hierarchical in nature. Type A contains the data that's needed to load the Type B controls and the Type B contains the data that's needed to load the Type C controls. The Type C control has a standard ComboBox in it for changing the values of the present items. In addition to the above structure, I have drag and dropping tied to the PreviewMouseLeftButtonDown event on both the Type A and Type B UserControl levels to handle reordering/deleting/etc commands in the GUI. All of this is working as intended. The Problem: When I attempt to change the value in the ComboBox, the SelectionChanged event never fires on the Type C "level" unless I'm careful enough to click on the borders/spacing in between any Type A or B controls. This happens when my ComboBox popout menu overlaps on either a Type A or B control located below itself. The selection events for Type A or B are firing instead of the Type C events, so the ComboBox is never changing its value reliably. In the debugger, the code for handling the drag and drop is triggering on the next ListBoxItem that's located underneath the ComboBox. Thoughts: Is there a way I can make my ComboBox popup take prevalence over the items behind it while double-nested in a ListBox (ie, ignore anything behind it while it's open)? Is there some way to reroute the incorrectly firing SelectionChanged events down to the ComboBox that's supposed to be triggering them?

    Read the article

  • Voting on Hacker News stories programmatically?

    - by igorgue
    I decided to write an app like: http://michaelgrinich.com/hackernews/ but for Android devices, my idea will use a web application backend (because I rather code in Python and for the web than completely in Java for Android devices). What I have right now implemented is something like this: $ curl -i http://localhost:8080/stories.json?page=1\&stories=1 HTTP/1.0 200 OK Date: Sun, 25 Apr 2010 07:59:37 GMT Server: WSGIServer/0.1 Python/2.6.5 Content-Length: 296 Content-Type: application/json [{"title": "Don\u2019t talk to aliens, warns Stephen Hawking", "url": "http://www.timesonline.co.uk/tol/news/science/space/article7107207.ece?", "unix_time": 1272175177, "comments": 15, "score": 38, "user": "chaostheory", "position": 1, "human_time": "Sun Apr 25 01:59:37 2010", "id": "1292241"}] The next step (and final I think) is voting, my design is doing something like this: $ curl -i http://localhost:8080/stories/1?vote=up -u username:password Will vote up and: $ curl -i http://localhost:8080/stories/1?vote=down -u username:password Down. I have no idea how to do it though... I was planning to use Twill but the login link is always different, e.g.: http://news.ycombinator.com/x?fnid=7u89ccHKln Later the Android app will consume this API. Any experience with programmatically browsing Hacker News?

    Read the article

  • Python/MySQL fails under Windows

    - by AP257
    I'm trying to get Python 2.6 to communicate with MySQL Server 5.1, under Windows XP, but I keep getting a strange error, "SystemError: NULL object passed to Py_BuildValue": >>> import MySQLdb as mysql >>> db = mysql.connect(user = "root", passwd="whatever", db="mysql", host="localh ost") >>> cu = db.cursor() >>> cu.execute("show tables") Traceback (most recent call last): File "<stdin>", line 1, in <module> File "C:\dirr\lib\site-packages\MySQLdb\cursors.py", line 173, in execu te self.errorhandler(self, exc, value) File "C:\ dirr\lib\site-packages\MySQLdb\connections.py", line 36, in de faulterrorhandler raise errorclass, errorvalue SystemError: NULL object passed to Py_BuildValue I thought it might be a character set problem, but I've tried setting and setting MySQL as UTF-8, and it hasn't made a difference. I guess there must be a problem with python-mysql. Can anyone help? UPDATE OK, python-mysql under windows is a bit of a nightmare, particularly with Python 2.6 it seems. Rather than installing python-mysql with pip, use this installer instead. That fixed it.

    Read the article

  • Is it possible to use SqlGeography with Linq to Sql?

    - by cofiem
    I've been having quite a few problems trying to use Microsoft.SqlServer.Types.SqlGeography. I know full well that support for this in Ling to Sql is not great. I've tried numerous ways, beginning with what would the expected way (Database type of geography, CLR type of SqlGeography). This produces the NotSupportedException, which is widely discussed via blogs. I've then gone down the path of treating the geography column as a varbinary(max), as geography is a UDT stored as binary. This seems to work fine (with some binary reading and writing extension methods). However, I'm now running into a rather obscure issue, which does not seem to have happened to many other people. System.InvalidCastException: Unable to cast object of type 'Microsoft.SqlServer.Types.SqlGeography' to type 'System.Byte[]'. This error is thrown from an ObjectMaterializer when iterating through a query. It seems to only occur when the tables containing geography columns are included in a query implicitly (ie. using the EntityRef<> properties to do joins). System.Data.Linq.SqlClient.ObjectReaderCompiler.ObjectReader`2.MoveNext() My question: If I'm retrieving the geography column as varbinary(max), I might expect the reverse error: can't cast byte[] to SqlGeography. That I would understand. This I don't. I do have some properies on the partial LINQ to SQL classes that hide the binary conversion... could those be the issue? Any help appreciated, and I know there's probably not enough information.

    Read the article

  • What's the boost way to create a functor that binds out an argument

    - by Mordachai
    I have need for a function pointer that takes two arguments and returns a string. I would like to pass an adapter that wraps a function that takes one argument, and returns the string (i.e. discard one of the arguments). I can trivially build my own adapter, that takes the 2 arguments, calls the wrapped function passing just the one argument through. But I'd much rather have a simple way to create an adapter on the fly, if there is an easy way to do so in C++/boost? Here's some details to make this a bit more concrete: typedef boost::function<CString (int,int)> TooltipTextFn; class MyCtrl { public: MyCtrl(TooltipTextFn callback = boost::bind(&MyCtrl::GetCellText, this, _1, _2)) : m_callback(callback) { } // QUESTION: how to trivially wrapper GetRowText to conform to TooltipTextFn by just discarding _2 ?! void UseRowText() { m_callback = boost::bind(&MyCtrl::GetRowText, this, _1, ??); } private: CString GetCellText(int row, int column); CString GetRowText(int row); TooltipTextFn m_callback; } Obviously, I can supply a member that adapts GetRowText to take two arguments and only passes the first to GetRowText() itself. But is there already a boost binder / adapter that lets me do that?

    Read the article

  • Destructors not called when native (C++) exception propagates to CLR component

    - by Phil Nash
    We have a large body of native C++ code, compliled into DLLs. Then we have a couple of dlls containing C++/CLI proxy code to wrap the C++ interfaces. On top of that we have C# code calling into the C++/CLI wrappers. Standard stuff, so far. But we have a lot of cases where native C++ exceptions are allowed to propagate to the .Net world and we rely on .Net's ability to wrap these as System.Exception objects and for the most part this works fine. However we have been finding that destructors of objects in scope at the point of the throw are not being invoked when the exception propagates! After some research we found that this is a fairly well known issue. However the solutions/ workarounds seem less consistent. We did find that if the native code is compiled with /EHa instead of /EHsc the issue disappears (at least in our test case it did). However we would much prefer to use /EHsc as we translate SEH exceptions to C++ exceptions ourselves and we would rather allow the compiler more scope for optimisation. Are there any other workarounds for this issue - other than wrapping every call across the native-managed boundary in a (native) try-catch-throw (in addition to the C++/CLI layer)?

    Read the article

  • Wait on multiple condition variables on Linux without unnecessary sleeps?

    - by Joseph Garvin
    I'm writing a latency sensitive app that in effect wants to wait on multiple condition variables at once. I've read before of several ways to get this functionality on Linux (apparently this is builtin on Windows), but none of them seem suitable for my app. The methods I know of are: Have one thread wait on each of the condition variables you want to wait on, which when woken will signal a single condition variable which you wait on instead. Cycling through multiple condition variables with a timed wait. Writing dummy bytes to files or pipes instead, and polling on those. #1 & #2 are unsuitable because they cause unnecessary sleeping. With #1, you have to wait for the dummy thread to wake up, then signal the real thread, then for the real thread to wake up, instead of the real thread just waking up to begin with -- the extra scheduler quantum spent on this actually matters for my app, and I'd prefer not to have to use a full fledged RTOS. #2 is even worse, you potentially spend N * timeout time asleep, or your timeout will be 0 in which case you never sleep (endlessly burning CPU and starving other threads is also bad). For #3, pipes are problematic because if the thread being 'signaled' is busy or even crashes (I'm in fact dealing with separate process rather than threads -- the mutexes and conditions would be stored in shared memory), then the writing thread will be stuck because the pipe's buffer will be full, as will any other clients. Files are problematic because you'd be growing it endlessly the longer the app ran. Is there a better way to do this? Curious for answers appropriate for Solaris as well.

    Read the article

< Previous Page | 371 372 373 374 375 376 377 378 379 380 381 382  | Next Page >