Search Results

Search found 5903 results on 237 pages for 'generic variance'.

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 25/237 | < Previous Page | 21 22 23 24 25 26 27 28 29 30 31 32  | Next Page >

  • Create a Generic IEnumerable<T> given a IEnumerable and the member datatypes

    - by ilias
    Hi, I get an IEnumerable which I know is a object array. I also know the datatype of the elements. Now I need to cast this to an IEnumerable<T, where T is a supplied type. For instance IEnumerable results = GetUsers(); IEnumerable<T> users = ConvertToTypedIEnumerable(results, typeof(User)); I now want to cast/ convert this to IEnumerable<User. Also, I want to be able to do this for any type. I cannot use IEnumerable.Cast<, because for that I have to know the type to cast it to at compile time, which I don't have. I get the type and the IEnumerable at runtime. - Thanks

    Read the article

  • Java Builder pattern with Generic type bounds

    - by I82Much
    Hi all, I'm attempting to create a class with many parameters, using a Builder pattern rather than telescoping constructors. I'm doing this in the way described by Joshua Bloch's Effective Java, having private constructor on the enclosing class, and a public static Builder class. The Builder class ensures the object is in a consistent state before calling build(), at which point it delegates the construction of the enclosing object to the private constructor. Thus public class Foo { // Many variables private Foo(Builder b) { // Use all of b's variables to initialize self } public static final class Builder { public Builder(/* required variables */) { } public Builder var1(Var var) { // set it return this; } public Foo build() { return new Foo(this); } } } I then want to add type bounds to some of the variables, and thus need to parametrize the class definition. I want the bounds of the Foo class to be the same as that of the Builder class. public class Foo<Q extends Quantity> { private final Unit<Q> units; // Many variables private Foo(Builder<Q> b) { // Use all of b's variables to initialize self } public static final class Builder<Q extends Quantity> { private Unit<Q> units; public Builder(/* required variables */) { } public Builder units(Unit<Q> units) { this.units = units; return this; } public Foo build() { return new Foo<Q>(this); } } } This compiles fine, but the compiler is allowing me to do things I feel should be compiler errors. E.g. public static final Foo.Builder<Acceleration> x_Body_AccelField = new Foo.Builder<Acceleration>() .units(SI.METER) .build(); Here the units argument is not Unit<Acceleration> but Unit<Length>, but it is still accepted by the compiler. What am I doing wrong here? I want to ensure at compile time that the unit types match up correctly.

    Read the article

  • Castle Windsor upgrade causes TypeLoadException for generic types

    - by Neil Barnwell
    I have the following mapping in my Castle Windsor xml file which has worked okay (unchanged) for some time: <component id="defaultBasicRepository" service="MyApp.Models.Repositories.IBasicRepository`1, MyApp.Models" type="MyApp.Models.Repositories.Linq.BasicRepository`1, MyApp.Models" lifestyle="perWebRequest"/> I got this from the Windsor documentation at http://www.castleproject.org/container/documentation/v1rc3/usersguide/genericssupport.html. Since I upgraded Windsor, I now get the following exception at runtime: Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.TypeLoadException: GenericArguments[0], 'T', on 'MyApp.Models.Repositories.Linq.BasicRepository`1[TEntity]' violates the constraint of type parameter 'TEntity'. Source Error: Line 44: public static void ConfigureIoC() Line 45: { Line 46: var windsor = new WindsorContainer("Windsor.xml"); Line 47: Line 48: ServiceLocator.SetLocatorProvider(() = new WindsorServiceLocator(windsor)); I'm using ASP.NET MVC 1.0, Visual Studio 2008 and Castle Windsor as downloaded from http://sourceforge.net/projects/castleproject/files/InversionOfControl/2.1/Castle-Windsor-2.1.1.zip/download Can anyone shed any light on this? I'm sure the upgrade of Castle Windsor is what caused it - it's been working well for ages.

    Read the article

  • Noise Estimation / Noise Measurement in Image

    - by Drazick
    Hello. I want to estimate the noise in an image. Let's assume the model of an Image + White Noise. Now I want to estimate the Noise Variance. My method is to calculate the Local Variance (3*3 up to 21*21 Blocks) of the image and then find areas where the Local Variance is fairly constant (By calculating the Local Variance of the Local Variance Matrix). I assume those areas are "Flat" hence the Variance is almost "Pure" noise. Yet I don't get constant results. Is there a better way? Thanks.

    Read the article

  • Java generics parameters with base of the generic parameter

    - by Iulian Serbanoiu
    Hello, I am wondering if there's an elegant solution for doing this in Java (besides the obvious one - of declaring a different/explicit function. Here is the code: private static HashMap<String, Integer> nameStringIndexMap = new HashMap<String, Integer>(); private static HashMap<Buffer, Integer> nameBufferIndexMap = new HashMap<Buffer, Integer>(); // and a function private static String newName(Object object, HashMap<Object, Integer> nameIndexMap){ .... } The problem is that I cannot pass nameStringIndexMap or nameBufferIndexMap parameters to the function. I don't have an idea about a more elegant solution beside doing another function which explicitly wants a HashMap<String, Integer> or HashMap<Buffer, Integer> parameter. My question is: Can this be made in a more elegant solution/using generics or something similar? Thank you, Iulian

    Read the article

  • Is it possible to create a generic Util Function to be used in Eval Page

    - by Nassign
    I am currently binding a Nullable bit column to a listview control. When you declare a list view item I need to handle the case when the null value is used instead of just true or false. <asp:Checkbox ID="Chk1" runat="server" Checked='<%# HandleNullableBool(Eval("IsUsed")) %>' /> Then in the page I add a HandleNullableBool() function inside the ASPX page. protected static bool HandleNullableBool(object value) { return (value == null) ? false : (bool)value; } This works fine but I need to use this in several pages so I tried creating a utility class with a static HandleNullableBool. But using it in the asp page does not work. Is there a way to do this in another class instead of the ASPX page? <asp:Checkbox ID="Chk1" runat="server" Checked='<%# Util.HandleNullableBool(Eval("IsUsed")) %>' />

    Read the article

  • Generic HTTP Handler in ASP.Net

    - by Bruno Brant
    Hello all, I want to write a custom HTTP Handler in ASP.Net (I'm using C# currently) that filters all requests to, say, .aspx files, and then, depending on the page name that comes with the requests, I redirect the user to a page. So far, I've written a handler that filter "*", that is, everything. Let's say I receive a request for "Page.aspx", and want to send the user to "AnotherPage.aspx". So I call Redirect on that response and pass "AnotherPage.aspx" as the new page. The problem is that this will once more trigger my handler, which will do nothing. This will leave the user without any response. So, is there a way to send the request to the other handlers (cascade the message) once I've dealt with it? Thanks, Bruno

    Read the article

  • Modeling a Generic Relationship in a Database

    - by StevenH
    This is most likely one for all you sexy DBAs out there: How would I effieciently model a relational database whereby I have a field in an "Event" table which defines a "SportType". This "SportsType" field can hold a link to different sports tables E.g. "FootballEvent", "RubgyEvent", "CricketEvent" and "F1 Event". Each of these Sports tables have different fields specific to that sport. My goal is to be able to genericly add sports types in the future as required, yet hold sport specific event data (fields) as part of my Event Entity. Is it possible to use an ORM such as NHibernate / Entity framework which would reflect such a relationship? I have thrown together a quick C# example to express my intent at a higher level: public class Event<T> where T : new() { public T Fields { get; set; } public Event() { EventType = new T(); } } public class FootballEvent { public Team CompetitorA { get; set; } public Team CompetitorB { get; set; } } public class TennisEvent { public Player CompetitorA { get; set; } public Player CompetitorB { get; set; } } public class F1RacingEvent { public List<Player> Drivers { get; set; } public List<Team> Teams { get; set; } } public class Team { public IEnumerable<Player> Squad { get; set; } } public class Player { public string Name { get; set; } public DateTime DOB { get; set;} }

    Read the article

  • Casting generics and the generic type

    - by Kragen
    Consider, I have the following 3 classes / interfaces: class MyClass<T> { } interface IMyInterface { } class Derived : IMyInterface { } And I want to be able to cast a MyClass<Derived> into a MyClass<IMyInterface> or visa-versa: MyClass<Derived> a = new MyClass<Derived>(); MyClass<IMyInterface> b = (MyClass<IMyInterface>)a; But I get compiler errors if I try: Cannot convert type 'MyClass<Derived>' to 'MyClass<IMyInterface>' I'm sure there is a very good reason why I cant do this, but I can't think of one. As for why I want to do this - The scenario I'm imagining is one whereby you ideally want to work with an instance of MyClass<Derived> in order to avoid lots of nasty casts, however you need to pass your instance to an interface that accepts MyClass<IMyInterface>. So my question is twofold: Why can I not cast between these two types? Is there any way of keeping the niceness of working with an instance of MyClass<Derived> while still being able to cast this into a MyClass<IMyInterface>?

    Read the article

  • Checking to see if a generic class is inherited from an interface

    - by SnOrfus
    I've got a class that inherits from an interface. That interface defines an event that I'd like to subscribe to in the calling code. I've tried a couple of things, but they all resolve to false (where I know it's true). How can I check to see if a class implements a specific interface. Here's what I've tried (note, the object in question is a usercontrol that implements MyInterface, stored in an array of controls, only some of which implement MyInterface - it is not null): if (this.controls[index].GetType().IsSubclassOf(typeof(MyInterface))) ((MyInterface)this.controls[index]).Event += this.Handler; if (this.controls[index].GetType().IsAssignableFrom(typeof(MyInterface))) ((MyInterface)this.controls[index]).Event += this.Handler; if (this.controls[index].GetType() == typeof(MyInterface)) ((MyInterface)this.controls[index]).Event += this.Handler; All to no avail.

    Read the article

  • Bind postback data from a strong type view of type List<T>

    - by Robert Koritnik
    I have a strong type view of type List<List<MyViewModelClass>> The outer list will always have two lists of List<MyViewModelClass>. For each of the two outer lists I want to display a group of checkboxes. Each set can have an arbitrary number of choices. My view model class looks similar to this: public class MyViewModelClass { public Area Area { get; set; } public bool IsGeneric { get; set; } public string Code { get; set; } public bool IsChecked { get; set; } } So the final view will look something like: Please select those that apply: First set of choices: x Option 1 x Option 2 x Option 3 etc. Second set of choices: x Second Option 1 x Second Option 2 x Second Option 3 x Second Option 4 etc. Checkboxes should display MyViewModelClass.Area.Name, and their value should be related to MyViewModelClass.Area.Id. Checked state is of course related to MyViewModel.IsChecked. Question I wonder how should I use Html.CheckBox() or Html.CheckBoxFor() helper to display my checkboxes? I have to get these values back to the server on a postback of course. I would like to have my controller action like one of these: public ActionResult ConsumeSelections(List<List<MyViewModelClass>> data) { // process data } public ActionResult ConsumeSelections(List<MyViewModelClass> first, List<MyViewModelClass> second) { // process data } If it makes things simpler, I could make a separate view model type like: public class Options { public List First { get; set; } public List Second { get; set; } } As well as changing my first version of controller action to: public ActionResult ConsumeSelections(Options data) { // process data }

    Read the article

  • Self closing Html Generic Control?

    - by Chalkey
    I am writing a bit of code to add a link tag to the head tag in the code behind... i.e. HtmlGenericControl css = new HtmlGenericControl("link"); css.Attributes["rel"] = "Stylesheet"; css.Attributes["type"] = "text/css"; css.Attributes["href"] = String.Format("/Assets/CSS/{0}", cssFile); to try and achieve something like... <link rel="Stylesheet" type="text/css" href="/CSS/Blah.css" /> I am using the HtmlGenericControl to achieve this... the issue I am having is that the control ultimatly gets rendered as... <link rel="Stylesheet" type="text/css" href="/CSS/Blah.css"></link> I cant seem to find what I am missing to not render the additional </link>, I assumed it should be a property on the object. Am I missing something or is this just not possible with this control? Thanks

    Read the article

  • how to use anonymous generic delegate in C# 2.0

    - by matti
    Hi. I have a class called NTree: class NTree<T> { public NTree(T data) { this.data = data; children = new List<NTree<T>>(); _stopTraverse = false; } ... public void Traverse(NTree<T> node, TreeVisitor<T> visitor) { try { _stopTraverse = false; Traverse(node, visitor); } finally { _stopTraverse = false; } } private void TraverseInternal(NTree<T> node, TreeVisitor<T> visitor) { if (_stopTraverse) return; if (!visitor(node.data)) { _stopTraverse = true; } foreach (NTree<T> kid in node.children) Traverse(kid, visitor); } When I try to use Traverse with anonymous delegate I get: Argument '2': cannot convert from 'anonymous method' to 'NisConverter.TreeVisitor' The code: tTable srcTable = new tTable(); DataRow[] rows; rootTree.Traverse(rootTree, delegate(TableRows tr) { if (tr.TableName == srcTable.mappingname) { rows = tr.Rows; return false; } }); This however produces no errors: static bool TableFinder<TableRows>(TableRows tr) { return true; } ... rootTree.Traverse(rootTree, TableFinder); I have tried to put "arrowhead-parenthisis" and everything to anonymous delegate but it just does not work. Please help me! Thanks & BR -Matti

    Read the article

  • Generic Dictionary and generating a hashcode for multi-part key

    - by Andrew
    I have an object that has a multi-part key and I am struggling to find a suitable way override GetHashCode. An example of what the class looks like is. public class wibble{ public int keypart1 {get; set;} public int keypart2 {get; set;} public int keypart3 {get; set;} public int keypart4 {get; set;} public int keypart5 {get; set;} public int keypart6 {get; set;} public int keypart7 {get; set;} public single value {get; set;} } Note in just about every instance of the class no more than 2 or 3 of the keyparts would have a value greater than 0. Any ideas on how best to generate a unique hashcode in this situation? I have also been playing around with creating a key that is not unique, but spreads the objects evenly between the dictionaries buckets and then storing objects with matched hashes in a List< or LinkedList< or SortedList<. Any thoughts on this?

    Read the article

  • Deserialize generic collections - coming up empty

    - by AC
    I've got a settings object for my app that has two collections in it. The collections are simple List generics that contain a collection of property bags. When I serialize it, everything is saved with no problem: XmlSerializer x = new XmlSerializer(settings.GetType()); TextWriter tw = new StreamWriter(@"c:\temp\settings.cpt"); x.Serialize(tw, settings); However when I deserialize it, everything is restored except for the two collections (verified by setting a breakpoint on the setters: XmlSerializer x = new XmlSerializer(typeof(CourseSettings)); XmlReader tr = XmlReader.Create(@"c:\temp\settings.cpt"); this.DataContext = (CourseSettings)x.Deserialize(tr); What would cause this? Everything is pretty vanilla... here's a snippet from the settings object... omitting most of it. The PresentationSourceDirectory works just fine, but the PresentationModules' setter isn't hit: private string _presentationSourceDirectory = string.Empty; public string PresentationSourceDirectory { get { return _presentationSourceDirectory; } set { if (_presentationSourceDirectory != value) { OnPropertyChanged("PresentationSourceDirectory"); _presentationSourceDirectory = value; } } } private List<Module> _presentationModules = new List<Module>(); public List<Module> PresentationModules { get { var sortedModules = from m in _presentationModules orderby m.ModuleOrder select m; return sortedModules.ToList<Module>(); } set { if (_presentationModules != value) { _presentationModules = value; OnPropertyChanged("PresentationModules"); } } }

    Read the article

  • Generic collection as a Java method argument

    - by Guido
    Is there any way to make this work in Java? public static void change(List<? extends Object> list, int position1, int position2) { Object obj = list.get(position1); list.set(position1, list.get(position2)); list.set(position2, obj); } The only way I've successfully avoided warnings and errors is this: public static <T> T change(List<T> list, int position1, int position2) { T obj = list.get(position1); list.set(position1, list.get(position2)); list.set(position2, obj); return obj; } but I don't like to be forced to return a value.

    Read the article

  • Java generic return type

    - by Colby77
    Hi, I'd like to write a method that can accept a type param (or whatever the method can figure out the type from) and return a value of this type so I don't have to cast the return type. Here is a method: public Object doIt(Object param){ if(param instanceof String){ return "string"; }else if(param instanceof Integer){ return 1; }else{ return null; } } When I call this method, and pass in it a String, even if I know the return type will be a String I have to cast the return Object. This is similar to the int param. How shall I write this method to accept a type param, and return this type?

    Read the article

  • Open Source Utilization Questions: How do you lone wold programmers best take advantage of open sour

    - by Funkyeah
    For Clarity: So you come up with an idea for a new program and want to start hacking, but you also happen to be a one-man army. How do you programming dynamos best find and utilize existing open-source software to give you the highest jumping off point possible when diving into your new project? When you do jump in where the shit do you start from? Any imaginary scenarios would be welcome, e.g. a shitty example might be utilizing a open-source database with an open-source IM client as a starting off point to a make a new client where you could tag and store conversations and query those tags at a later time.

    Read the article

  • Generic function pointers in C

    - by Lucas
    I have a function which takes a block of data and the size of the block and a function pointer as argument. Then it iterates over the data and performes a calculation on each element of the data block. The following is the essential outline of what I am doing: int myfunction(int* data, int size, int (*functionAsPointer)(int)){ //walking through the data and calculating something for (int n = 0; n < size; n++){ data[n] = (*function)(data[n]); } } The functions I am passing as arguments look something like this: int mycalculation(int input){ //doing some math with input //... return input; } This is working well, but now I need to pass an additional variable to my functionpointer. Something along the lines int mynewcalculation(int input, int someVariable){ //e.g. input = input * someVariable; //... return input; } Is there an elegant way to achieve this and at the same time keeping my overall design idea?

    Read the article

  • Concrete Implementation of Generic Form Not Working in Designer

    - by Dov
    I have a base class, defined as below (I'm also using DevExpress components): public abstract partial class BaseFormClass<R> : XtraForm where R : DataRow { ... } Contrary to what I've read from elsewhere, I'm still able to design this class. I didn't have to create a concrete class from it to do so. But, when I create a concrete class descended from it (as below), that class won't work in the designer. public partial class ConcreteFormClass : BaseFormClass<StronglyTypedRow> { ... } I get this message: The designer could not be shown for this file because none of the classes within it can be designed. The designer inspected the following classes in the file: ConcreteFormClass --- The base class 'BaseFormClass' could not be loaded. Ensure the assembly has been referenced and that all projects have been built. Has anyone seen this before? Any sort of known workaround?

    Read the article

  • How to explain traits?

    - by Partial
    How would you explain traits to a new C++ programmer? How would you explain traits to a C programmer? How would you explain traits to a Java/Ruby/Python/C# or any other OOP language programmer?

    Read the article

  • ASP.NET MVC PartialView generic ModelView

    - by Greg Ogle
    I have an ASP.NET MVC application which I want to dynamically pick the partial view and what data gets passed to it, while maintaining strong types. So, in the main form, I want a class that has a view model that contains a generically typed property which should contain the data for the partial view's view model. public class MainViewModel<T> { public T PartialViewsViewModel { get; set; } } In the User Control, I would like something like: Inherits="System.Web.Mvc.ViewUserControl<MainViewModel<ParticularViewModel>>" %> Though in my parent form, I must put Inherits="System.Web.Mvc.ViewPage<MainViewModel<ParticularViewModel>>" %> for it to work. Is there a way to work around this? The use case is to make the user control pluggable. I understand that I could inherit a base class, but that would put me back to having something like a dictionary instead of a typed view model.

    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 | 21 22 23 24 25 26 27 28 29 30 31 32  | Next Page >