Search Results

Search found 21343 results on 854 pages for 'pass by reference'.

Page 689/854 | < Previous Page | 685 686 687 688 689 690 691 692 693 694 695 696  | Next Page >

  • Swipe left/right to push next/previous details view

    - by Youssef
    I am working on a ios application, using storyboard. I have a simple table view with rows. Each row has a "key" string to identify it. When the user clicks on a row I push the next view "DetailsViewController" and pass the "key" as a parameter in the prepareForSegue method. The data in the second view will change based on the "key" passed. In the "DetailsViewController" I want to add a swipe gesture, when the user swipes right, I want to push the next details view. It will be as if he clicked on the next row in the table view. So to rephrase, the user has 2 ways of switching between items: he can click the item in the table view and the details view will show, he can then go back and select another item. Or he can click on a row, and in the details view he can swipe left and right to see the previous/next item. i added the uigesture recognizer: UISwipeGestureRecognizer *recognizer; recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipe:)]; [recognizer setDirection:UISwipeGestureRecognizerDirectionRight]; [[self view] addGestureRecognizer:recognizer]; - (void) handleSwipe:(UISwipeGestureRecognizer *) sender { //I want to go to the next item in the tableview } I hope I was clear. Thank you.

    Read the article

  • C++ Multiple inheritance with interfaces?

    - by umanga
    Greetings all, I come from Java background and I am having difficulty with multiple inheritance. I have an interface called IView which has init() method.I want to derive a new class called PlaneViewer implementing above interface and extend another class. (QWidget). My implementation is as: IViwer.h (only Header file , no CPP file) : #ifndef IVIEWER_H_ #define IVIEWER_H_ class IViewer { public: //IViewer(); ///virtual //~IViewer(); virtual void init()=0; }; #endif /* IVIEWER_H_ */ My derived class. PlaneViewer.h #ifndef PLANEVIEWER_H #define PLANEVIEWER_H #include <QtGui/QWidget> #include "ui_planeviewer.h" #include "IViewer.h" class PlaneViewer : public QWidget , public IViewer { Q_OBJECT public: PlaneViewer(QWidget *parent = 0); ~PlaneViewer(); void init(); //do I have to define here also ? private: Ui::PlaneViewerClass ui; }; #endif // PLANEVIEWER_H PlaneViewer.cpp #include "planeviewer.h" PlaneViewer::PlaneViewer(QWidget *parent) : QWidget(parent) { ui.setupUi(this); } PlaneViewer::~PlaneViewer() { } void PlaneViewer::init(){ } My questions are: Is it necessary to declare method init() in PlaneViewer interface also , because it is already defined in IView? 2.I cannot complie above code ,give error : PlaneViewer]+0x28): undefined reference to `typeinfo for IViewer' collect2: ld returned 1 exit status Do I have to have implementation for IView in CPP file?

    Read the article

  • Alpha blending colors in .NET Compact Framwork 2.0

    - by Adam Haile
    In the Full .NET framework you can use the Color.FromArgb() method to create a new color with alpha blending, like this: Color blended = Color.FromArgb(alpha, color); or Color blended = Color.FromArgb(alpha, red, green , blue); However in the Compact Framework (2.0 specifically), neither of those prototypes are valid, you only get: Color.FromArgb(int red, int green, int blue); and Color.FromArgb(int val); The first one, obviously, doesn't even let you enter an alpha value, but the documentation for the latter shows that "val" is a 32bit ARGB value (as 0xAARRGGBB as opposed to the standard 24bit 0xRRGGBB), so it would make sense that you could just build the ARGB value and pass it to the function. I tried this with the following: private Color FromARGB(byte alpha, byte red, byte green, byte blue) { int val = (alpha << 24) | (red << 16) | (green << 8) | blue; return Color.FromArgb(val); } But no matter what I do, the alpha blending never works, the resulting color always as full opacity, even when setting the alpha value to 0. Has anyone gotten this to work on Compact Framework?

    Read the article

  • Lazarus Pascal - DB Connection - clarification

    - by itsols
    The following code is from the docs here: Program ConnectDB var AConnection : TSQLConnection; Procedure CreateConnection; begin AConnection := TIBConnection.Create(nil); AConnection.Hostname := 'localhost'; AConnection.DatabaseName := '/opt/firebird/examples/employee.fdb'; AConnection.UserName := 'sysdba'; AConnection.Password := 'masterkey'; end; begin CreateConnection; AConnection.Open; if Aconnection.Connected then writeln('Succesful connect!') else writeln('This is not possible, because if the connection failed, ' + 'an exception should be raised, so this code would not ' + 'be executed'); AConnection.Close; AConnection.Free; end. The main body of the code makes sense to me BUT I don't get where TSQLConnection came from. I cannot use CTRL + Space to autocomplete it either, which means my program has no reference to it. I'm trying to connect to Postgres by the way. Can someone please state what TSQLConnection is? Thanks!

    Read the article

  • error with std::ostringsteam and std::string

    - by pyCthon
    Hi i want to save many different csv files from a function with a naming convention based on a different double value. I do this with a for loop and pass a string value to save each .csv file differently. Below is an example of what I'm trying to do the desired result would be 1.1_file.csv 1.2_file.csv but instead i get 1.1_file.csv 1.11.2_file.csv Here is a working sample code, what can i do to fix this #include <sstream> #include <iomanip> #include <cmath> #include <iostream> #include <vector> int main(){ std::string file = "_file.csv"; std::string s; std::ostringstream os; double x; for(int i = 0; i < 10; i++){ x = 0.1 + 0.1 *i; os << std::fixed << std::setprecision(1); os << x; s = os.str(); std::cout<<s+file<<std::endl; s.clear(); } return 0; }

    Read the article

  • Image resizing - sometimes very poor quality?!

    - by eWolf
    I'm resizing some images to the screen resolution of the user; if the aspect ratio is wrong, the image should be cut. My code looks like this: protected void ConvertToBitmap(string filename) { var origImg = System.Drawing.Image.FromFile(filename); var widthDivisor = (double)origImg.Width / (double)System.Windows.Forms.Screen.PrimaryScreen.Bounds.Width; var heightDivisor = (double)origImg.Height / (double)System.Windows.Forms.Screen.PrimaryScreen.Bounds.Height; int newWidth, newHeight; if (widthDivisor < heightDivisor) { newWidth = (int)((double)origImg.Width / widthDivisor); newHeight = (int)((double)origImg.Height / widthDivisor); } else { newWidth = (int)((double)origImg.Width / heightDivisor); newHeight = (int)((double)origImg.Height / heightDivisor); } var newImg = origImg.GetThumbnailImage(newWidth, newHeight, null, IntPtr.Zero); newImg.Save(this.GetBitmapPath(filename), System.Drawing.Imaging.ImageFormat.Bmp); } In most cases, this works fine. But for some images, the result has an extremely poor quality. It looks like the would have been resized to something very small (thumbnail size) and enlarged again.. But the resolution of the image is correct. What can I do? Example orig image: Example resized image: Note: I have a WPF application but I use the WinForms function for resizing because it's easier and because I already need a reference to System.Windows.Forms for a tray icon.

    Read the article

  • Using XPath on String in Android (JAVA)

    - by Rav
    I am looking for some examples of using xpath in Android? Or if anyone can share their experiences. I have been struggeling to make tail or head of this problem :-( I have a string that contains a standard xml file. I believe I need to convert that into an xml document. I have found this code which I think will do the trick: public static Document stringToDom(String xmlSource) throws SAXException, ParserConfigurationException, IOException { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = factory.newDocumentBuilder(); return builder.parse(new InputSource(new StringReader(xmlSource))); } Next steps Assuming the code above is OK, I need to apply xpath to get values from cat: "/animal/mammal/feline/cat" I look at the dev doc here: http://developer.android.com/reference/javax/xml/xpath/XPath.html and also look online, but I am not sure where to start! I have tried to use the following code: XPathFactory xPathFactory = XPathFactory.newInstance(); // To get an instance of the XPathFactory object itself. XPath xPath = xPathFactory.newXPath(); // Create an instance of XPath from the factory class. String expression = "SomeXPathExpression"; XPathExpression xPathExpression = xPath.compile(expression); // Compile the expression to get a XPathExpression object. Object result = xPathExpression.evaluate(xmlDocument); // Evaluate the expression against the XML Document to get the result. But I get "Cannot be resolved". Eclipse doesn't seem to be able to fix this import. I tried manually entering: javax.xml.xpath.XPath But this did not work. Does anyone know any good source code that I can utilise, for Android platform? 1.5

    Read the article

  • wpf & validation application block > message localization > messageTemplateResource Name&Type

    - by Shaboboo
    I'm trying to write validation rules for my data objects in a WPF application. I'm writing them in the configuration file, and so far they are working fine. I'm stumped on how to localize the messages using messageTemplateResourceName and messageTemplateResourceType. What I know is that the strings can be writen in a resource file, given a name and referenced by that name. I get the idea, but i haven't been able to make this work. <ruleset name="Rule Set"> <properties> <property name="StringValue"> <validator lowerBound="0" lowerBoundType="Ignore" upperBound="25" upperBoundType="Inclusive" negated="false" messageTemplate="" messageTemplateResourceName="msg1" messageTemplateResourceType="Resources" tag="" type="Microsoft.Practices.EnterpriseLibrary.Validation.Validators.StringLengthValidator, Microsoft.Practices.EnterpriseLibrary.Validation" name="String Length Validator" /> </property> </properties> </ruleset> Where is the resource file and what value do I pass to messageTemplateResourceType? I have tried writing the messages in the shell project's resource file but no sucess trying to retrieve the value. I only get the default built-in message. I've tried messageTemplateResourceType="typeof(Resources)" messageTemplateResourceType="Resources" messageTemplateResourceType="Resources.resx" messageTemplateResourceType="typeof(Shell)" messageTemplateResourceType="Shell" messageTemplateResourceType="Shell, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" I've also tried adding a new resource file in the shell project, and adding a resource file to the data object's library. I'm all out of ideas Does anyone have any suggestions? I'm not even married to the idea of resource files, so if there are other ways to localize these messages I'd love to know! thanks

    Read the article

  • ViewModel Views relation/link/syncroniztion

    - by mehran
    Third try to describing problem: Try 1: Sunchronizing view model and view Try2: WPF ViewModel not active presenter Try3: I have some class for view models: public class Node : INotifyPropertyChanged { Guid NodeId { get; set; } public string Name { get; set; } } public class Connection: INotifyPropertyChanged { public Node StartNode { get; set; } public Node EndNode { get; set; } } public class SettingsPackModel { public List<Node> Nodes { get; private set; } public List<Connection> Connections { get; private set; } } I also have some templates to displays these models: <DataTemplate DataType="{x:Type vm:Node}">…</DataTemplate> <DataTemplate DataType="{x:Type vm:Connection}"> <my:ConnectionElment StartNodeElment="???" EndNodeElment="???"> </my:ConnectionElment> <DataTemplate> But the problem is that DataTemplate for Connection need reference ot two element of type UIElement , how can I pass these two, how can I fill ??? in above expression?

    Read the article

  • Are MEF's ComposableParts contracts instance-based?

    - by Dave
    I didn't really know how to phrase the title of my questions, so my apologies in advance. I read through parts of the MEF documentation to try to find the answer to my question, but couldn't find it. I'm using ImportMany to allow MEF to create multiple instances of a specific plugin. That plugin Imports several parts, and within calls to a specific instance, it wants these Imports to be singletons. However, what I don't want is for all instances of this plugin to use the same singleton. For example, let's say my application ImportManys Blender appliances. Every time I ask for one, I want a different Blender. However, each Blender Imports a ControlPanel. I want each Blender to have its own ControlPanel. To make things a little more interesting, each Blender can load BlendPrograms, which are also contained within their own assemblies, and MEF takes care of this loading. A BlendProgram might need to access the ControlPanel to get the speed, but I want to ensure that it is accessing the correct ControlPanel (i.e. the one that is associated with the Blender that is associated with the program!) This diagram might clear things up a little bit: As the note shows, I believe that the confusion could come from an inherently-poor design. The BlendProgram shouldn't touch the ControlPanel directly, and instead perhaps the BlendProgram should get the speed via the Blender, which will then delegate the request to its ControlPanel. If this is the case, then I assume the BlendProgram needs to have a reference to a specific Blender. In order to do this, is the right way to leverage MEF and use an ImportingConstructor for BlendProgram, i.e. [ImportingConstructor] public class BlendProgram : IBlendProgram { public BlendProgram( Blender blender) {} } And if this is the case, how do I know that MEF will use the intended Blender plugin?

    Read the article

  • C# class design - expose variables for reading but not setting

    - by James Brauman
    I have a a polygon class which stores a list of Microsoft.Xna.Framework.Vector2 as the vertices of the polygon. Once the polygon is created, I'd like other classes to be able to read the position of the vertices, but not change them. I am currently exposing the vertices through this field: /// <summary> /// Gets the vertices stored for this polygon. /// </summary> public List<Vector2> Vertices { get { return _vertices; } } List<Vector2> _vertices; However you can change any vertex using code like: Polygon1.Vertices[0] = new Vector2(0, 0); or Polygon1.Vertices[0].X = 0; How can I limit other classes to be able to only read the properties of these vertices, and not be able to set a new one to my List? The only thing I can think of is to pass a copy to classes that request it. Note that Vector2 is a struct that is part of the XNA framework and I cannot change it. Thanks.

    Read the article

  • How to link pnglite library in c?

    - by zaplec
    Hi, I installed from kubuntu's package management this handy pnglite library. It contains just one header file "pnglite.h" and one object file "pnglite.o". I have found out where those files are, but I don't know how to link them. I'm using netbeans, but don't know how to link them in there. Also I don't understand how to link them at console. I have a little test program that I would like to test, but I get the error message "undefined reference to function: XXXXXXX". Both netbeans and at console I'm using gcc. That header file is in /usr/include directory, object file is in /usr/lib directory and my test program is under my programming directory at my home directory. Should I put that header and object into the same directory as where my source is? Or is there a way to link them from their current locations? I know that it should be possible to link them from where they are at the moment and I would like to know and understand how to do that. Any help will be appreciated :)

    Read the article

  • How does a client find the port number of a server?

    - by Jonathan
    Hello all, I am currently learning about basic networking in java. I have been playing around with the server and client relationship between two of my computers. However, I cannot figure out how distributed programs (say, a videogame), can not only find the 'host' computer, but also the port number on which the server is running in order to create a Socket between the two computers. The only way I really see to create a Socket is with an already known IP Address, and with a known port number. How do you search a LAN network for another computer (host) searching for clients? How do you determine what port the server is located on without 'pinging' all available ports for a response (which, I understand, is bad form... Something about 'server attack'...)? In such a situation as a video game, there can be any number of computers on the same network, and any number of them might be attempting to host, or otherwise running the application. Any other important information, or perhaps reference to a more detailed tutorial than the one I am using, regarding making connections on so very little information on the client side would be appreciated. Many thanks, Jonathan

    Read the article

  • C# Process Binary File, Multi-Thread Processing

    - by washtik
    I have the following code that processes a binary file. I want to split the processing workload by using threads and assigning each line of the binary file to threads in the ThreadPool. Processing time for each line is only small but when dealing with files that might contain hundreds of lines, it makes sense to split the workload. My question is regarding the BinaryReader and thread safety. First of all, is what I am doing below acceptable. I have a feeling it would be better to pass only the binary for each line to the PROCESS_Binary_Return_lineData method. Please note the code below is conceptual. I looking for a but of guidance on this as my knowledge of multi-threading is in its infancy. Perhaps there is a better way to achieve the same result, i.e. split processing of each binary line. var dic = new Dictionary<DateTime, Data>(); var resetEvent = new ManualResetEvent(false); using (var b = new BinaryReader(File.Open(Constants.dataFile, FileMode.Open, FileAccess.Read, FileShare.Read))) { var lByte = b.BaseStream.Length; var toProcess = 0; while (lByte >= DATALENGTH) { b.BaseStream.Position = lByte; lByte = lByte - AB_DATALENGTH; ThreadPool.QueueUserWorkItem(delegate { Interlocked.Increment(ref toProcess); var lineData = PROCESS_Binary_Return_lineData(b); lock(dic) { if (!dic.ContainsKey(lineData.DateTime)) { dic.Add(lineData.DateTime, lineData); } } if (Interlocked.Decrement(ref toProcess) == 0) resetEvent.Set(); }, null); } } resetEvent.WaitOne();

    Read the article

  • How to customize the process employed by WCF when serializing contract method arguments?

    - by mark
    Dear ladies and sirs. I would like to formulate a contrived scenario, which nevertheless has firm actual basis. Imagine a collection type COuter, which is a wrapper around an instance of another collection type CInner. Both implement IList (never mind the T). Furthermore, a COuter instance is buried inside some object graph, the root of which (let us refer to it as R) is returned from a WCF service method. My question is how can I customize the WCF serialization process, so that when R is returned, the request to serialize the COuter instance will be routed through my code, which will extract CInner and pass it to the serializer instead. Thus the receiving end still gets R, only no COuter instance is found in the object graph. I hoped that http://stackoverflow.com/questions/2220516/how-does-wcf-serialize-the-method-call will contain the answer, unfortunately the article mentioned there (http://msdn.microsoft.com/en-us/magazine/cc163569.aspx) only barely mentions that advanced serialization scenarios are possible using IDataContractSurrogate interface, but no details are given. I am, on the other hand, would really like to see a working example. Thank you very much in advance.

    Read the article

  • ASP.Net MVC: Showing the same data using different layouts...

    - by vdh_ant
    Hi guys I'm wanting to create a page that allows the users to select how they would like to view their data - i.e. summary (which supports grouping), grid (which supports grouping), table (which supports grouping), map, time line, xml, json etc. Now each layout would probably have different use a different view model, which inherit from a common base class/view model. The reason being that each layout needs the object structure that it deals with to be different (some need hierarchical others a flatter structure). Each layout would call the same repository method and each layout would support the same functionality, i.e. searching and filtering (hence these controls would be shared between layouts). The main exception to this would be sorting which only grid and table views would need to support. Now my question is given this what do people think is the best approach. Using DisplayFor to handle the rendering of the different types? Also how do I work this with the actions... I would imagine that I would use the one action, and pass in the layout types, but then how does this support the grouping required for the summary, grid and table views. Do i treat each grouping as just a layout type Also how would this work from a URL point of view - what do people think is the template to support this layout functionality Cheers Anthony

    Read the article

  • Passing PHP variables trough functions?

    - by Mateus Nunes
    I'm facing some troubles to pass php variables value trough functions,every time i try to use a variable inside one of my functions its value becomes nil,let me be more specific.I have the following code in my php file: $myvar = $Session['username']; function updateuserinformation(){ if(trim($_FILES["fileUpload"]["tmp_name"]) != ""){ $images = $_FILES["fileUpload"]["tmp_name"]; $new_images = "thumbnails_".$_FILES["fileUpload"]["name"]; copy($_FILES["fileUpload"]["tmp_name"],"Photos/".$_FILES["fileUpload"]["name"]); $width=200; //*** Fix Width & Heigh (Autu caculate) ***// $size=GetimageSize($images); $height=round($width*$size[1]/$size[0]); $images_orig = ImageCreateFromJPEG($images); $photoX = ImagesX($images_orig); $photoY = ImagesY($images_orig); $images_fin = ImageCreateTrueColor($width, $height); ImageCopyResampled($images_fin, $images_orig, 0, 0, 0, 0, $width+1, $height+1, $photoX, $photoY); ImageJPEG($images_fin,"Photos/".$new_images); ImageDestroy($images_orig); ImageDestroy($images_fin); print $data["foo"]; echo"$myvar"; mysql_query("UPDATE users SET userpictureaddress = 'http://www.litsdevelopment.com/litsapplication/userimages/MATEUS' WHERE username = 'Mateus' "); } } I trying to use the $myvar value in my function but every time i run the code it just doesn't work,i've already tried global,globals,arrays and session for nothing worked.Of corse i'm making a little mistake in some part of it,but anyone know what is the correct way to do this?

    Read the article

  • setting default value of superglobal

    - by Prasoon Saurav
    I have been working on a Timesheet Management website. I have my home page as index.php //index.php <?php session_start(); if($_SESSION['logged']=='set') { $x=$_SESSION['username']; echo '<div align="right">'; echo 'Welcome ' .$x.'<br/>'; echo'<a href="logout.php" class="links">&nbsp;<b><u>Logout</u></b></a>' ; } else if($_SESSION['logged']='unset') { echo'<form id="searchform" method="post" action="processing.php"> <div> <div align="right"> Username&nbsp;<input type="text" name="username" id="s" size="15" value="" /> &nbsp;Password&nbsp;<input type="password" name="pass" id="s" size="15" value="" /> <input type="submit" name="submit" value="submit" /> </div> <br /> </div> </form> '; } ?> The problem I am facing is that during the first run of this script I get an error Notice: Undefined index: logged in C:\wamp\www\ps\index.php but after refreshing the page the error vanishes. How can I correct this problem? logged is a variable which helps determine whether the user is logged in or not. When the user is logged in $_SESSION['logged'] is set, otherwise unset. I want the default value of $_SESSION['logged'] to be unset prior to the execution of the script. How can I solve this problem?

    Read the article

  • WPF - How to stop an ItemsControl psuedo-grid's columns from dancing/jumping around during layout

    - by Drew Noakes
    Several other questions on SO have come to the same conclusion I have -- using an ItemsControl with a DataTemplate for each item constructed to position items such that they resemble a grid is much simpler (especially to format) than using a ListView. The code resembles: <StackPanel Grid.IsSharedSizeScope="True"> <!-- Header --> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" SharedSizeGroup="Column1" /> <ColumnDefinition Width="Auto" SharedSizeGroup="Column2" /> </Grid.ColumnDefinitions> <TextBlock Grid.Column="0" Text="Column Header 1" /> <TextBlock Grid.Column="1" Text="Column Header 2" /> </Grid> <!-- Items --> <ItemsControl ItemsSource="{Binding Path=Values, Mode=OneWay}"> <ItemsControl.ItemTemplate> <DataTemplate> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" SharedSizeGroup="Column1" /> <ColumnDefinition Width="Auto" SharedSizeGroup="Column2" /> </Grid.ColumnDefinitions> <TextBlock Grid.Column="0" Text="{Binding ColumnProperty1}" /> <TextBlock Grid.Column="1" Text="{Binding ColumnProperty2}" /> </Grid> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> </StackPanel> The problem I'm seeing is that whenever I swap the object to which the ItemsSource is bound (it's an ObservableCollection that I replace the reference to, rather than clear and re-add), the entire 'grid' dances about for a few seconds. Presumably it is making a few layout passes to get all the Auto-width columns to match up. This is very distracting for my users and I'd like to get it sorted out. Has anyone else seen this?

    Read the article

  • How to manipulate *huge* amounts of data

    - by Alejandro
    Hi there! I'm having the following problem. I need to store huge amounts of information (~32 GB) and be able to manipulate it as fast as possible. I'm wondering what's the best way to do it (combinations of programming language + OS + whatever you think its important). The structure of the information I'm using is a 4D array (NxNxNxN) of double-precission floats (8 bytes). Right now my solution is to slice the 4D array into 2D arrays and store them in separate files in the HDD of my computer. This is really slow and the manipulation of the data is unbearable, so this is no solution at all! I'm thinking on moving into a Supercomputing facility in my country and store all the information in the RAM, but I'm not sure how to implement an application to take advantage of it (I'm not a professional programmer, so any book/reference will help me a lot). An alternative solution I'm thinking on is to buy a dedicated server with lots of RAM, but I don't know for sure if that will solve the problem. So right now my ignorance doesn't let me choose the best way to proceed. What would you do if you were in this situation? I'm open to any idea. Thanks in advance!

    Read the article

  • How to bundle extension methods requiring configuration in a library

    - by Greg
    Hi, I would like to develop a library that I can re-use to add various methods involved in navigating/searching through a graph (nodes/relationships, or if you like vertexs/edges). The generic requirements would be: There are existing classes in the main project that already implement the equivalent of the graph class (which contains the lists of nodes / relationships), node class and relationship class (which links nodes together) - the main project likely already has persistence mechanisms for the info (e.g. these classes might be built using Entity Framework for persistance) Methods would need to be added to each of these 3 classes: (a) graph class - methods like "search all nodes", (b) node class - methods such as "find all children to depth i", c) relationship class - methods like "return relationship type", "get parent node", "get child node". I assume there would be a need to inform the library with the extending methods the class names for the graph/node/relationships table (as different project might use different names). To some extent it would need to be like how a generics collection works (where you pass the classes to the collection so it knows what they are). Need to be a way to inform the library of which node property to use for equality checks perhaps (e.g. if it were a graph of webpages the equality field to use might be the URI path) I'm assuming that using abstract base classes wouldn't really work as this would tie usage down to have to use the same persistence approach, and same class names etc. Whereas really I want to be able to, for a project that has "graph-like" characteristics, the ability to add graph searching/walking methods to it.

    Read the article

  • Why does Microsoft advise against readonly fields with mutable values?

    - by Weeble
    In the Design Guidelines for Developing Class Libraries, Microsoft say: Do not assign instances of mutable types to read-only fields. The objects created using a mutable type can be modified after they are created. For example, arrays and most collections are mutable types while Int32, Uri, and String are immutable types. For fields that hold a mutable reference type, the read-only modifier prevents the field value from being overwritten but does not protect the mutable type from modification. This simply restates the behaviour of readonly without explaining why it's bad to use readonly. The implication appears to be that many people do not understand what "readonly" does and will wrongly expect readonly fields to be deeply immutable. In effect it advises using "readonly" as code documentation indicating deep immutability - despite the fact that the compiler has no way to enforce this - and disallows its use for its normal function: to ensure that the value of the field doesn't change after the object has been constructed. I feel uneasy with this recommendation to use "readonly" to indicate something other than its normal meaning understood by the compiler. I feel that it encourages people to misunderstand the meaning of "readonly", and furthermore to expect it to mean something that the author of the code might not intend. I feel that it precludes using it in places it could be useful - e.g. to show that some relationship between two mutable objects remains unchanged for the lifetime of one of those objects. The notion of assuming that readers do not understand the meaning of "readonly" also appears to be in contradiction to other advice from Microsoft, such as FxCop's "Do not initialize unnecessarily" rule, which assumes readers of your code to be experts in the language and should know that (for example) bool fields are automatically initialised to false, and stops you from providing the redundancy that shows "yes, this has been consciously set to false; I didn't just forget to initialize it". So, first and foremost, why do Microsoft advise against use of readonly for references to mutable types? I'd also be interested to know: Do you follow this Design Guideline in all your code? What do you expect when you see "readonly" in a piece of code you didn't write?

    Read the article

  • How to use the LINQ where expression?

    - by NullReference
    I'm implementing the service \ repository pattern in a new project. I've got a base interface that looks like this. Everything works great until I need to use the GetMany method. I'm just not sure how to pass a LINQ expression into the GetMany method. For example how would I simply sort a list of objects of type name? nameRepository.GetMany( ? ) public interface IRepository<T> where T : class { void Add(T entity); void Update(T entity); void Delete(T entity); void Delete(Expression<Func<T, bool>> where); T GetById(long Id); T GetById(string Id); T Get(Expression<Func<T, bool>> where); IEnumerable<T> GetAll(); IEnumerable<T> GetMany(Expression<Func<T, bool>> where); } public virtual IEnumerable<T> GetMany(Expression<Func<T, bool>> where) { return dbset.Where(where).ToList(); }

    Read the article

  • Flash Without a SWF File?

    - by PeterAllenWebb
    Is there any way to embed Flash completely in HTML, without reference to an external SWF file? I ask because I would like to send an HTML file as an email attachment that the recipient will open in a browser and fill out as a form. The last step is that they will copy the result to their clipboard, paste it into a new message, and email it back. I cannot reliably copy to the clipboard with JavaScript because of the security issues, but there are simple Flash apps to add that capability. I know I could just display the response text (which will be Base64 encoded) to the recipient and have them copy/paste, but it would be nice to provide this small convenience to them. Also, so you are aware, the text is often too large to include in an email using mailto. Yes. This needs to be done via email. The users have slow, occasional satellite email access and no other data connection to the interwebs. To make things worse, I cannot make them install anything. It is a difficult situation.

    Read the article

  • Do complex JOINs cause high coupling and maintenance problems ?

    - by ashkan.kh.nazary
    Our project has ~40 tables with complex relations.A colleague believes in using long join queries which enforces me to learn about tables outside of my module but I think I should not concern about tables not directly related to my module and use data access functions (written by those responsible for other modules) when I need data from them. Let me clarify: I am responsible for the ContactVendor module which enables the customers to contact the vendor and start a conversation about some specific product. Products module has it's own complex tables and relations with functions that encapsulate details (for example i18n, activation, product availability etc ...). Now I need to show the product title of some product related to some conversation between the vendor and customers. I may either write a long query that retrieves the product info along with conversation stuff in one shot (which enforces me to learn about Product tables) OR I may pass the relevant product_id to the get_product_info(int) function. First approach is obviously demanding and introduces many bad practices and things I normally consider fault in programming. The problem with the second approach seems to be the countless mini queries these access functions cause and performance loss is a concern when a loop tries to fetch product titles for 100 products using functions that each perform a separate query. So I'm stuck between "don't code to the implementation, code to interface" and performance. What is the right way of doing things ? UPDATE: I'm specially concerned about possible future modifications to those tables outside of my module. What if the Products module decided to change the way they are doing things? or for some reason modify the schema? It means some other modules would break or malfunction until the change is integrated to them. The usual ripple effect problem.

    Read the article

< Previous Page | 685 686 687 688 689 690 691 692 693 694 695 696  | Next Page >