Search Results

Search found 89926 results on 3598 pages for 'abstract data type'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 28/3598 | < Previous Page | 24 25 26 27 28 29 30 31 32 33 34 35  | Next Page >

  • Object of type "X" cannot be converted to object of type "X"

    - by Benjol
    (Can't believe this hasn't already been asked, but I can't find a dup) In Visual Studio with lots of projects, when I first open the solution, I sometimes get the warning Object of type "X" cannot be converted to object of type "X". Generally rebuilding seems to make it go away, but does anyone know what this is caused by, and how to avoid it? UPDATE I read somewhere that deleting all your resx files and rebuilding can help. I unthinkingly tried this. Not a good idea...

    Read the article

  • How to find out if an object is of <type> or a decendant of <type>

    - by Vaccano
    I have the following code: foreach (var control in this.Controls) { } I want to do something like control.Hide() in there. But the items in the this.Controls collection are not of type Control (they are Object). I can't seem to remember the safe way to cast this to call hide if it is really of type Control and do nothing otherwise. (I am a transplanted delphi programmer and I keep thinking something like control is Control.)

    Read the article

  • Creating a Type object corresponding to a generic type

    - by Alexey Romanov
    In Java, how can I construct a Type object for Map<String, String>? System.out.println(Map<String, String>.class); doesn't compile. One workaround I can think of is private Map<String, String> dummy() { throw new Error(); } Type mapStringString = Class.forName("ThisClass").getMethod("dummy", null).getGenericReturnType(); Is this the correct way?

    Read the article

  • changing restriction on simple type in extended complex type

    - by rotary_engine
    I am trying to create a schema that has 2 address types. The first AdressType requires an element Line 1 to have a value at least 10 characters. The second type OtherAdressType derives from this with the same elements, but does not require a value for Line 1. I've tried different ways but always get schema errors, this error is: Invalid particle derivation by restriction - 'Derived element '{namespace}:Line1' is not a valid restriction of base element '{namespace}:Line1' according to Elt:Elt -- NameAndTypeOK.'. If I add a type xs:string to OtherAdressType:Line1 then I get other errors. <xs:complexType name="AdressType"> <xs:sequence> <xs:element name="Line1" minOccurs="1" maxOccurs="1"> <xs:simpleType> <xs:restriction base="xs:string"> <xs:minLength value="10" /> </xs:restriction> </xs:simpleType> </xs:element> <xs:element name="Line2" type="xs:string" minOccurs="1" maxOccurs="1" /> </xs:sequence> </xs:complexType> <xs:complexType name="OtherAdressType"> <xs:complexContent> <xs:restriction base="AdressType"> <xs:sequence> <xs:element name="Line1" nillable="true"> <xs:simpleType> <xs:restriction base="xs:string"> <xs:minLength value="0" /> </xs:restriction> </xs:simpleType> </xs:element> <xs:element name="Line2" type="xs:string" minOccurs="1" maxOccurs="1" /> </xs:sequence> </xs:restriction> </xs:complexContent> </xs:complexType>

    Read the article

  • Info on type family instances

    - by yairchu
    Intro: While checking out snoyman's "persistent" library I found myself wanting ghci's (or another tool) assistance in figuring out stuff. ghci's :info doesn't seem to work as nicely with type-families and data-families as it does with "plain" types: > :info Maybe data Maybe a = Nothing | Just a -- Defined in Data.Maybe ... > :info Persist.Key Potato -- "Key Potato" defined in example below data family Persist.Key val -- Defined in Database.Persist ... (no info on the structure/identity of the actual instance) One can always look for the instance in the source code, but sometimes it could be hard to find it and it may be hidden in template-haskell generated code etc. Code example: {-# LANGUAGE FlexibleInstances, GeneralizedNewtypeDeriving, MultiParamTypeClasses, TypeFamilies, QuasiQuotes #-} import qualified Database.Persist as Persist import Database.Persist.Sqlite as PSqlite PSqlite.persistSqlite [$persist| Potato name String isTasty Bool luckyNumber Int UniqueId name |] What's going on in the code example above is that Template-Haskell is generating code for us here. All the extensions above except for QuasiQuotes are required because the generated code uses them. I found out what Persist.Key Potato is by doing: -- test.hs: test = PSqlite.persistSqlite [$persist| ... -- ghci: > :l test.hs > import Language.Haskell.TH > import Data.List > runQ test >>= putStrLn . unlines . filter (isInfixOf "Key Potato") . lines . pprint where newtype Database.Persist.Key Potato = PotatoId Int64 type PotatoId = Database.Persist.Key Potato Question: Is there an easier way to get information on instances of type families and data families, using ghci or any other tool?

    Read the article

  • How can I make an "abstract" enum in a .NET class library?

    - by Lazlo
    I'm making a server library in which the packet association is done by enum. public enum ServerOperationCode : byte { LoginResponse = 0x00, SelectionResponse = 0x01, BlahBlahResponse = 0x02 } public enum ClientOperationCode : byte { LoginRequest = 0x00, SelectionRequest = 0x01, BlahBlahRequest = 0x02 } That works fine when you're working in your own project - you can compare which enum member is returned (i.e. if (packet.OperationCode == ClientOperationCode.LoginRequest)). However, since this is a class library, the user will have to define its own enum. Therefore, I have two enums to add as "abstract" - ServerOperationCode and ClientOperationCode. I know it's not possible to implement abstract enums in C#. How would I go doing this?

    Read the article

  • How do I ensure my abstract class's function can only operate on extenders of the same type as the c

    - by incrediman
    For example, let's say this is my abstract class: abstract class A{ int x; int y; void foo(A fooMe); } ...and B and C are two classes which extend A. What I want is for B to only be able to call foo() on other Bs, and for C to only be able to call foo() on other Cs. But I want this to be out of the hands of the programmer who's extending my A class - that is, I want a way to ensure this functionality within As code alone. What can I do? (If possible) I'd like to avoid any hack or generics solution that's too messy - I still want foo to be able to be called like this, for example: B b=new B(); B bb=new B(); bb.foo(b);

    Read the article

  • Nested/Sub data types in haskell

    - by Tom Carstens
    So what would be nice is if you could do something like the following (not necessarily with this format, just the general idea): data Minor = MinorA | MinorB data Major = Minor | MajorB isMinor :: Major -> Bool isMinor Minor = True isMinor _ = False So isMinor MinorA would report True (instead of an error.) At the moment you might do something like: data Major = MinorA | MinorB | MajorB isMinor :: Major -> Bool isMinor MinorA = True isMinor MinorB = True isMinor _ = False It's not terrible or anything, but it doesn't expand nicely (as in if Minor when up to MinorZ this would be terribly clunky). To avoid that problem you can wrap Minor: data Minor = MinorA | MinorB data Major = MajorA Minor | MajorB isMinor :: Major -> Bool isMinor (MajorA _) = True isMinor _ = False But now you have to make sure to wrap your Minors to use them as a Major... again not terrible; just doesn't really express the semantics I'd like very well (i.e. Major can be any Minor or MajorB). The first (legal) example is "Major can be MinorA..." but doesn't have any knowledge of Minor and the second is "Major can be MajorA that takes a Minor..." p.s. No, this isn't really about anything concrete.

    Read the article

  • Display a input type=file over another input type=file

    - by Kevin Sedgley
    WARNING: Lengthy description coming up! I have written an uploader based upon APC progress uploader for PHP. This works fine and dandy, but the script as a whole (apc etc) is intended to be used only for those with Javascript. To achieve this, I have searched for any input type=file, and replaced these with an absolutely positioned form that appears over the original area where the old file input area was. The reasons for this are so the new uploader can submit to a hidden in page IFrame has to be in a seperate <form> in order to submit to the APC reciever to display the progress upload bar. allows it to be used within any form with an input type=file throughout the site I have used JQuery to do this, with the following code: Original HTML form code: <div><input type="file" name="media" id="media" /></div> Find position of div block code: // get the parent div, and properties thereof parentDiv = $(this).closest('div'); w = $(parentDiv).width(); h = $(parentDiv).height(); loc = $(parentDiv).offset(); Locate new block over old block: $('#_sender').appendTo('body').css({left:loc.left,top:loc.top,position:'absolute',zIndex:400,height:h,width:w}).show(); This works fine, and shows over the old block OK. The problem: When other elements in the DOM before or above it change (in this case a "tree view" selector is pushing the old block down) the new upload form gets moved over other elements. Is there a JQuery (or JS) method for changing this upon DOM change? Some kind of .onchange for the page?! Or an .onmove for the original block? Thanks in advance you lovely people Before DOM change: . After: .

    Read the article

  • Get type of the parameter from list of objects, templates, C++

    - by CrocodileDundee
    This question follows to my previous question Get type of the parameter, templates, C++ There is the following data structure: Object1.h template <class T> class Object1 { private: T a1; T a2; public: T getA1() {return a1;} typedef T type; }; Object2.h template <class T> class Object2: public Object1 <T> { private: T b1; T b2; public: T getB1() {return b1;} } List.h template <typename Item> struct TList { typedef std::vector <Item> Type; }; template <typename Item> class List { private: typename TList <Item>::Type items; }; Is there any way how to get type T of an object from the list of objects (i.e. Object is not a direct parameter of the function but a template parameter)? template <class Object> void process (List <Object> *objects) { typename Object::type a1 = objects[0].getA1(); // g++ error: 'Object1<double>*' is not a class, struct, or union type } But his construction works (i.e. Object represents a parameter of the function) template <class Object> void process (Object *o1) { typename Object::type a1 = o1.getA1(); // OK }

    Read the article

  • Declaring an object of a conditional type with a System.Type

    - by Chapso
    I am attempting to launch a specific form depending on the selected node of a treeview on the doubleclick event. The code I need to use to launch the form is a little bulky becuase I have to ensure that the form is not disposed, and that the form is not already open, before launching a new instance. I'd like to have all of this checking happen in one place at the end of the function, which means that I have to be able to pass the right form type to the code at the end. I'm trying to do this with a System.Type, but that doesn't seem to be working. Could someone point me in the right direction, please? With TreeView.SelectedNode Dim formType As Type Select Case .Text Case "Email to VPs" formType = EmailForm.GetType() Case "Revise Replacers" formType = DedicatedReplacerForm.GetType() Case "Start Email" formType = EmailForm.GetType() End Select Dim form As formType Dim form As formType Try form = CType(.Tag, formType) If Not form.IsDisposed Then form.Activate() Exit Sub End If Catch ex As NullReferenceException 'This will error out the first time it is run as the form has not yet ' been defined. End Try form = New formType form.MdiParent = Me .Tag = form CType(TreeView.SelectedNode.Tag, Form).Show() End With

    Read the article

  • warning: format ‘%s’ expects type ‘char *’, but argument 2 has type ‘int’

    - by pyz
    code: #include <stdio.h> #include <stdlib.h> #include <netdb.h> #include <sys/socket.h> int main(int argc, char **argv) { char *ptr, **pptr; struct hostent *hptr; char str[32]; //ptr = argv[1]; ptr = "www.google.com"; if ((hptr = gethostbyname(ptr)) == NULL) { printf("gethostbyname error for host:%s\n", ptr); } printf("official hostname:%s\n", hptr->h_name); for (pptr = hptr->h_aliases; *pptr != NULL; pptr++) printf(" alias:%s\n", *pptr); switch (hptr->h_addrtype) { case AF_INET: case AF_INET6: pptr = hptr->h_addr_list; for (; *pptr != NULL; pptr++) printf(" address:%s\n", inet_ntop(hptr->h_addrtype, *pptr, str, sizeof(str))); break; default: printf("unknown address type\n"); break; } return 0; } compiler output below: zhumatoMacBook:CProjects zhu$ gcc gethostbynamedemo.c gethostbynamedemo.c: In function ‘main’: gethostbynamedemo.c:31: warning: format ‘%s’ expects type ‘char *’, but argument 2 has type ‘int’

    Read the article

  • Using Lazy<T> and abstract wrapper class to lazy-load complex system parameters

    - by DigiMortal
    .NET Framework 4.0 introduced new class called Lazy<T> and I wrote blog post about it: .Net Framework 4.0: Using System.Lazy<T>. One thing is annoying for me – we have to keep lazy loaded value and its value loader as separate things. In this posting I will introduce you my Lazy<T> wrapper for complex to get system parameters that uses template method to keep lazy value loader in parameter class. Problem with original implementation Here’s the sample code that shows you how Lazy<T> is usually used. This is just sample code, don’t focus on the fact that this is dummy console application. class Program {     static void Main(string[] args)     {         var temperature = new Lazy<int>(LoadMinimalTemperature);           Console.WriteLine("Minimal room temperature: " + temperature.Value);         Console.ReadLine();     }       protected static int LoadMinimalTemperature()     {         var returnValue = 0;           // Do complex stuff here           return true;     } } The problem is that our class with many lazy loaded properties will grow messy if it has all value loading code inside it. This code may be complex for more than one parameter and in this case it is better to use separate class for this parameter. Defining base class for parameters As a first step I will define base class for all lazy-loaded parameters. This class is wrapper around Lazy<T> and it also offers one template method that parameter classes have to override to provide loaded data. public abstract class LazyParameter<T> {     private Lazy<T> _lazyParam;       public LazyParameter()     {         _lazyParam = new Lazy<T>(Load);     }       protected abstract T Load();       public T Value     {         get { return _lazyParam.Value; }     } } It is also possible to extend Lazy<T> but I don’t prefer to do it as Lazy<T> has six constructors we have to take care of. Also I don’t like to expose Lazy<T> public interface to users of my parameter classes. Creating parameter class Now it’s time to create our first parameter class. Notice how few stuff we have in this class besides overridden Load() method. public class MinimalRoomTemperature : LazyParameter<int> {     protected override int Load()     {         var returnValue = 0;           // Do complex stuff here           return returnValue;     } } Using parameter class is simple. Here’s my test code. class Program {     static void Main(string[] args)     {         var parameter = new MinimalRoomTemperature();         Console.WriteLine("Minimal room temperature: " + parameter.Value);         Console.ReadLine();     } } Conclusion Lazy<T> is useful class that you usually don’t want to use outside from API-s. I like this class but I don’t like when people are using this class directly in application code. In this posting I showed you how to use Lazy<T> with wrapper class to get complex parameter loading code out from classes that use this parameter. We ended up with generic base class for parameters that you can also use as base for other similar classes (you have to find better name to base class in this case).

    Read the article

  • Pure virtual or abstract, what's in a name?

    - by Steven Jeuris
    While discussing a question about virtual functions on Stack Overflow, I wondered whether there was any official naming for pure (abstract) and non-pure virtual functions. I always relied on wikipedia for my information, which states that pure and non-pure virtual functions are the general term. Unfortunately, the article doesn't back it up with a origin or references. To quote Jon Skeet's answer to my reply that pure and non-pure are the general term used: @Steven: Hmm... possibly, but I've only ever seen it in the context of C++ before. I suspect anyone talking about them is likely to have a C++ background :) Did the terms originate from C++, or were they first defined or implemented in a earlier language, and are they the 'official' scientific terms?

    Read the article

  • WCF/ADO.NET Data Services - Could not load type 'System.Data.Services.Providers.IDataServiceUpdatePr

    Ad:: SharePoint 2007 Training in .NET 3.5 technologies (more information). This feed URL has been discontinued. Please update your reader's URL to : http://feeds.feedburner.com/winsmarts Read full article .... ...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

    Read the article

  • Absent Code attribute in method that is not native or abstract

    - by kerry
    I got the following, quite puzzling error today when running a unit test: java.lang.ClassFormatError: Absent Code attribute in method that is not native or abstract in class file javax/servlet/http/Cookie A google search found this post, which explains that it is caused by having an interface in the classpath, and not an actual implementation. In this case it’s the java-ee interface. To fix this I added the jetty servlet api implementation to my pom: jetty javax.servlet test Piece of cake. I have run in to this before, so I figured I would capture the fix here in case I run in to it again.

    Read the article

  • Data, Log and Temp file placement

    - by jchang
    First especially for all the people with SAN storage, drive letters are of no consequence. What matters is the actual physical disk layout. Forget capacity, pay attention to the number of spindles supporting each RAID group. If the RAID group is shared with other application, make sure there the SLA guarantees read and write latency. One very large company conducted a stress test in the QA environment. The SAN admin carved the LUNs from the same pool of disks as production, but thought he had a really...(read more)

    Read the article

  • Live from ODTUG - Big Data and SQL session #2

    - by Jean-Pierre Dijcks
    Sitting in Dominic Delmolino's session at ODTUG (KScope 12). If the session count at conferences is any indication then we will see more and more people start to deploy MapReduce in the database. And yes, that would be with SQL and PL/SQL first and foremost. Both Dominic and our own Bryn Llewellyn are doing MapReduce in the database presentations.  Since I have seen both, I would advice people to first look through Dominic's session to get a good grasp on what mappers do and what reducers do, then dive into Bryn's for a bunch of PL/SQL example. The thing I like about Dominic's is the last slide (a recursive WITH statement) to do this in SQL... Now I am hoping that next year we will see tools vendors show off how they work with Hadoop and MapReduce (at least talking about the concepts!!).

    Read the article

  • How can i move towards the Business intelliegnce/ data mining fields from software developer

    - by user1758043
    I am working as python developer and i work with djnago. I also do some web scrapping and building spiders and bots. Now from there i want to make my move to Business intelligence. I just want to know how can i move into that field. because as companies are not going to hire me in that field directly , i just want to know how can i make transistions. I was thinking of first work as Database developer in sql and then i can see futher. But i want from you guys so that i can start learning that stuff so that i can chnage jobs keeping that in mind. here in my area there are plent of jobs in all area but i need to know hoe to transitio and what thing i should learn before making that transition. Here JObs are plenty so if i know my stuff , getting job is piece of cake becaus ethey don't ahve any persons. same jobs keep getting advertised for months and months

    Read the article

  • How abstract should you get with BDD

    - by Newton
    I was writing some tests in Gherkin (using Cucumber/Specflow). I was wondering how abstract should I get with my tests. In order to not make this open-ended, which of the following statements is better for BDD: Given I am logged in with email [email protected] and password 12345 When I do something Then something happens as opposed to Given I am logged in as the Administrator When I do something Then something happens The reason I am confused is because 1 is more based on the behaviour (filing in email and password) and 2 is easier to process and write the tests.

    Read the article

  • Better data structure for a game like Bubble Witch

    - by CrociDB
    I'm implementing a bubble-witch-like game (http://www.king.com/games/puzzle-games/bubble-witch/), and I was thinking on what's the better way to store the "bubbles" and to work with. I thought of using graphs, but that might be too complex for a trivial thing. Thought of a matrix, just like a tile map, but that might get too 'workaroundy'. I don't know. I'll be doing in Flash/AS3, though. Thanks. :)

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 24 25 26 27 28 29 30 31 32 33 34 35  | Next Page >