Search Results

Search found 37088 results on 1484 pages for 'object element'.

Page 505/1484 | < Previous Page | 501 502 503 504 505 506 507 508 509 510 511 512  | Next Page >

  • Understanding how texCUBE works and writing cubemaps properly into a cube rendertarget

    - by cubrman
    My goal is to create accurate reflections, sampled from a dynamic cubemap, for specific 3d objects (mostly lights) in XNA 4.0. To sample the cubemap I compute the 3d reflection vector in a classic way: half3 ReflectionVec = reflect(-directionToCamera, Normal.rgb); I then use the vector to get the actual reflected color: half3 ReflectionCol = texCUBElod(ReflectionSampler, float4(ReflectionVec, 0)); The cubemap I am sampling from is a RenderTarget with 6 flat faces. So my question is, given the 3d world position of an arbitrary 3d object, how can I make sure that I get accurate reflections of this object, when I re-render the cubemap. Should I build the ViewProjection matrix in a specific way? Or is there any other approach?

    Read the article

  • How to use OO for data analysis? [closed]

    - by Konsta
    In which ways could object-orientation (OO) make my data analysis more efficient and let me reuse more of my code? The data analysis can be broken up into get data (from db or csv or similar) transform data (filter, group/pivot, ...) display/plot (graph timeseries, create tables, etc.) I mostly use Python and its Pandas and Matplotlib packages for this besides some DB connectivity (SQL). Almost all of my code is a functional/procedural mix. While I have started to create a data object for a certain collection of time series, I wonder if there are OO design patterns/approaches for other parts of the process that might increase efficiency?

    Read the article

  • Stairway to XML: Level 5 - The XML exist() and nodes() Methods

    The XML exist() method is used, often in a WHERE clause, to check the existence of an element within an XML document or fragment. The nodes() method lets you shred an XML instance and return the information as relational data. 12 essential tools for database professionalsThe SQL Developer Bundle contains 12 tools designed with the SQL Server developer and DBA in mind. Try it now.

    Read the article

  • Generically correcting data before save with Entity Framework

    - by koevoeter
    Been working with Entity Framework (.NET 4.0) for a week now for a data migration job and needed some code that generically corrects string values in the database. You probably also have seen things like empty strings instead of NULL or non-trimmed texts ("United States       ") in "old" databases, and you don't want to apply a correcting function on every column you migrate. Here's how I've done this (extending the partial class of my ObjectContext):public partial class MyDatacontext{    partial void OnContextCreated()    {        SavingChanges += OnSavingChanges;    }     private void OnSavingChanges(object sender, EventArgs e)    {        foreach (var entity in GetPersistingEntities(sender))        {            foreach (var propertyInfo in GetStringProperties(entity))            {                var value = (string)propertyInfo.GetValue(entity, null);                 if (value == null)                {                    continue;                }                 if (value.Trim().Length == 0 && IsNullable(propertyInfo))                {                    propertyInfo.SetValue(entity, null, null);                }                else if (value != value.Trim())                {                    propertyInfo.SetValue(entity, value.Trim(), null);                }            }        }    }     private IEnumerable<object> GetPersistingEntities(object sender)    {        return ((ObjectContext)sender).ObjectStateManager            .GetObjectStateEntries(EntityState.Added | EntityState.Modified)             .Select(e => e.Entity);    }    private IEnumerable<PropertyInfo> GetStringProperties(object entity)    {        return entity.GetType().GetProperties()            .Where(pi => pi.PropertyType == typeof(string));    }    private bool IsNullable(PropertyInfo propertyInfo)    {        return ((EdmScalarPropertyAttribute)propertyInfo             .GetCustomAttributes(typeof(EdmScalarPropertyAttribute), false)            .Single()).IsNullable;    }}   Obviously you can use similar code for other generic corrections.

    Read the article

  • In an Entity-Component-System Engine, How do I deal with groups of dependent entities?

    - by John Daniels
    After going over a few game design patterns, I have settle with Entity-Component-System (ES System) for my game engine. I've reading articles (mainly T=Machine) and review some source code and I think I got enough to get started. There is just one basic idea I am struggling with. How do I deal with groups of entities that are dependent on each other? Let me use an example: Assume I am making a standard overhead shooter (think Jamestown) and I want to construct a "boss entity" with multiple distinct but connected parts. The break down might look like something like this: Ship body: Movement, Rendering Cannon: Position (locked relative to the Ship body), Tracking\Fire at hero, Taking Damage until disabled Core: Position (locked relative to the Ship body), Tracking\Fire at hero, Taking Damage until disabled, Disabling (er...destroying) all other entities in the ship group My goal would be something that would be identified (and manipulated) as a distinct game element without having to rewrite subsystem form the ground up every time I want to build a new aggregate Element. How do I implement this kind of design in ES System? Do I implement some kind of parent-child entity relationship (entities can have children)? This seems to contradict the methodology that Entities are just empty container and makes it feel more OOP. Do I implement them as separate entities, with some kind of connecting Component (BossComponent) and related system (BossSubSystem)? I can't help but think that this will be hard to implement since how components communicate seem to be a big bear trap. Do I implement them as one Entity, with a collection of components (ShipComponent, CannonComponents, CoreComponent)? This one seems to veer way of the ES System intent (components here seem too much like heavy weight entities), but I'm know to this so I figured I would put that out there. Do I implement them as something else I have mentioned? I know that this can be implemented very easily in OOP, but my choosing ES over OOP is one that I will stick with. If I need to break with pure ES theory to implement this design I will (not like I haven't had to compromise pure design before), but I would prefer to do that for performance reason rather than start with bad design. For extra credit, think of the same design but, each of the "boss entities" were actually connected to a larger "BigBoss entity" made of a main body, main core and 3 "Boss Entities". This would let me see a solution for at least 3 dimensions (grandparent-parent-child)...which should be more than enough for me. Links to articles or example code would be appreciated. Thanks for your time.

    Read the article

  • Where to store shaders

    - by Mark Ingram
    I have an OpenGL renderer which has a Scene member variable. The Scene object can contain N SceneObjects. I use these SceneObjects for storing the vertex position and any transforms. My question is, where should shaders be stored in this arrangement? I guess they need to be in a central location because multiple objects can use the same shader. But then each object needs access to the shader because it needs to set attributes into the shader. Does anyone have any advice?

    Read the article

  • Marketing Your Home Business Opportunity Online Using SEO

    Search engine optimisation (SEO) should be a crucial element of any online selling tactic. Websites which are not properly optimised for search engines will end in a considerable loss in terms of free advertising which is essentially gained from getting a good ranking by search engines. This post will give basic information on what SEO is and will make a case on why marketing your home online business opportunity requires at least some degree of SEO.

    Read the article

  • How to manage my model

    - by Christophe Debove
    I have in my model, a list of Classes : Player, NonPlayerCharacter, Monster, Item, NonMovableItem etc With AndEngine I've a list of sprite for each piece of my model, How can I manage the relashionship between my model's classes and the graphical elements, what is the degree of abstaction recommended for my problem? One sprite for one Model or one Model for one Sprite or n for n for exemple If I do drag&drop have I to make abstraction of the Sprite Class, another exemple a map is a List of sprite or a list of element of my model?

    Read the article

  • nVidia GeForce Go 7600? can it ever run unity?

    - by Khaled Musleh
    my laptop Toshiba Qosmio G30 has nVidia GeForce Go 7600 card and it suppose to support 3D . i run unity 2d now . I run 12.04 and the graphic driver is--VESA: G73 Board - toshg73m-- by UBUNTU. when i run /usr/lib/nux/unity_support_test -p then i get this list Not software rendered: no Not blacklisted: yes GLX fbconfig: yes GLX texture from pixmap: yes GL npot or rect textures: yes GL vertex program: yes GL fragment program: yes GL vertex buffer object: yes GL framebuffer object: yes GL version is 1.4+: yes Unity 3D supported: no the card is not blacklisted but a similar one with GT is! Do you think that there is a chance the laptop can run the unity 3d? and may be i could change the resolution of the screen to a higher one too! I tried all the nvidia drivers provided but none works (except 96 in ubuntu 12.04 ). i get a black screen or terminal screen. best wishes to all

    Read the article

  • Android Emulator - Ubuntu 12.04

    - by Aneesh karthik C
    When I type in the command @emulator Andreud where 'Andreud' is the name of the emulator I created. It gives the following errors and a blank screen in which I should get android home screen, icons, etc shows up. PVRDRIInitPVR2D: PVR2D device index (0)Failed to load libGL.so error libGL.so: cannot open shared object file: No such file or directory Failed to load libGL.so error libGL.so: cannot open shared object file: No such file or directory As per a comment I tried installing ia32-libs aneesh@nb14:~$ sudo apt-get install ia32-libs Reading package lists... Done Building dependency tree Reading state information... Done Package ia32-libs is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source E: Package 'ia32-libs' has no installation candidate I want the home screen to appear. Any help is greatly appreciated.

    Read the article

  • Mobile or the Science of Programming Languages

    - by user12652314
    Just two things to share today. First is some news in the mobile computing space and a pretty cool new relationship developing with DubLabs and AT&T to enable a student-centric mobile experience for our Campus Solution customers. And second, is an interesting article shared by a friend on Research in Programming Languages related to STEM education, a key story element to my project with Americas Cup and iED, but also to our national interest

    Read the article

  • Achieving more fluent movement

    - by Robin92
    I'm working on my first OpenGL 2D game and I've just locked the framerate of my game. However, the way objects move is far from satisfying: they tend to lag, which is shown in this video. I've thought how more fluent animation can be achieved and started getting segmentation faults due to accessing the same object by two different threads. I've tried the following threads' setting: Drawing, creating new objects Moving player, moving objects, deleting objects Currently my application uses this setting: Drawing, creating new objects, moving objects, deleting object Moving player Any ideas would be appreciated. EDIT: I've tried increasing the FPS limit but lags are noticeable even at 200 fps.

    Read the article

  • Powershell – script all objects on all databases to files

    - by Nigel Rivett
    <# This simple PowerShell routine scripts out all the user-defined functions, stored procedures, tables and views in all the databases on the server that you specify, to the path that you specify. SMO must be installed on the machine (it happens if SSMS is installed) To run - set the servername and path Open a command window and run powershell Copy the below into the window and press enter - it should run It will create the subfolders for the databases and objects if necessary. #> $path = “C:\Test\Script\" $ServerName = "MyServerNameOrIpAddress" [System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.SMO') $serverInstance = New-Object ('Microsoft.SqlServer.Management.Smo.Server') $ServerName $IncludeTypes = @(“tables”,”StoredProcedures”,"Views","UserDefinedFunctions") $ExcludeSchemas = @(“sys”,”Information_Schema”) $so = new-object (‘Microsoft.SqlServer.Management.Smo.ScriptingOptions’) $so.IncludeIfNotExists = 0 $so.SchemaQualify = 1 $so.AllowSystemObjects = 0 $so.ScriptDrops = 0 #Script Drop Objects $dbs=$serverInstance.Databases foreach ($db in $dbs) { $dbname = "$db".replace("[","").replace("]","") $dbpath = "$path"+"$dbname" + "\" if ( !(Test-Path $dbpath)) {$null=new-item -type directory -name "$dbname"-path "$path"} foreach ($Type in $IncludeTypes) { $objpath = "$dbpath" + "$Type" + "\" if ( !(Test-Path $objpath)) {$null=new-item -type directory -name "$Type"-path "$dbpath"} foreach ($objs in $db.$Type) { If ($ExcludeSchemas -notcontains $objs.Schema ) { $ObjName = "$objs".replace("[","").replace("]","") $OutFile = "$objpath" + "$ObjName" + ".sql" $objs.Script($so)+"GO" | out-File $OutFile #-Append } } } }

    Read the article

  • IsNullOrEmpty generic method for Array to avoid Re-Sharper warning

    - by Michael Freidgeim
    I’ve used the following extension method in many places. public static bool IsNullOrEmpty(this Object[] myArr) { return (myArr == null || myArr.Length == 0); }Recently I’ve noticed that Resharper shows warning covariant array conversion to object[] may cause an exception for the following codeObjectsOfMyClass.IsNullOrEmpty()I’ve resolved the issue by creating generic extension method public static bool IsNullOrEmpty<T>(this T[] myArr) { return (myArr == null || myArr.Length == 0); }Related linkshttp://connect.microsoft.com/VisualStudio/feedback/details/94089/add-isnullorempty-to-array-class    public static bool IsNullOrEmpty(this System.Collections.IEnumerable source)        {            if (source == null)                return true;            else            {                return !source.GetEnumerator().MoveNext();            }        }http://stackoverflow.com/questions/8560106/isnullorempty-equivalent-for-array-c-sharp

    Read the article

  • Passing a parameter so that it cannot be changed – C#

    - by nmarun
    I read this requirement of not allowing a user to change the value of a property passed as a parameter to a method. In C++, as far as I could recall (it’s been over 10 yrs, so I had to refresh memory), you can pass ‘const’ to a function parameter and this ensures that the parameter cannot be changed inside the scope of the function. There’s no such direct way of doing this in C#, but that does not mean it cannot be done!! Ok, so this ‘not-so-direct’ technique depends on the type of the parameter – a simple property or a collection. Parameter as a simple property: This is quite easy (and you might have guessed it already). Bulent Ozkir clearly explains how this can be done here. Parameter as a collection property: Obviously the above does not work if the parameter is a collection of some type. Let’s dig-in. Suppose I need to create a collection of type KeyTitle as defined below. 1: public class KeyTitle 2: { 3: public int Key { get; set; } 4: public string Title { get; set; } 5: } My class is declared as below: 1: public class Class1 2: { 3: public Class1() 4: { 5: MyKeyTitleList = new List<KeyTitle>(); 6: } 7: 8: public List<KeyTitle> MyKeyTitleList { get; set; } 9: public ReadOnlyCollection<KeyTitle> ReadonlyKeyTitleCollection 10: { 11: // .AsReadOnly creates a ReadOnlyCollection<> type 12: get { return MyKeyTitleList.AsReadOnly(); } 13: } 14: } See the .AsReadOnly() method used in the second property? As MSDN says it: “Returns a read-only IList<T> wrapper for the current collection.” Knowing this, I can implement my code as: 1: public static void Main() 2: { 3: Class1 class1 = new Class1(); 4: class1.MyKeyTitleList.Add(new KeyTitle { Key = 1, Title = "abc" }); 5: class1.MyKeyTitleList.Add(new KeyTitle { Key = 2, Title = "def" }); 6: class1.MyKeyTitleList.Add(new KeyTitle { Key = 3, Title = "ghi" }); 7: class1.MyKeyTitleList.Add(new KeyTitle { Key = 4, Title = "jkl" }); 8:  9: TryToModifyCollection(class1.MyKeyTitleList.AsReadOnly()); 10:  11: Console.ReadLine(); 12: } 13:  14: private static void TryToModifyCollection(ReadOnlyCollection<KeyTitle> readOnlyCollection) 15: { 16: // can only read 17: for (int i = 0; i < readOnlyCollection.Count; i++) 18: { 19: Console.WriteLine("{0} - {1}", readOnlyCollection[i].Key, readOnlyCollection[i].Title); 20: } 21: // Add() - not allowed 22: // even the indexer does not have a setter 23: } The output is as expected: The below image shows two things. In the first line, I’ve tried to access an element in my read-only collection through an indexer. It shows that the ReadOnlyCollection<> does not have a setter on the indexer. The second line tells that there’s no ‘Add()’ method for this type of collection. The capture below shows there’s no ‘Remove()’ method either, there-by eliminating all ways of modifying a collection. Mission accomplished… right? Now, even if you have a collection of different type, all you need to do is to somehow cast (used loosely) it to a List<> and then do a .AsReadOnly() to get a ReadOnlyCollection of your custom collection type. As an example, if you have an IDictionary<int, string>, you can create a List<T> of this type with a wrapper class (KeyTitle in our case). 1: public IDictionary<int, string> MyDictionary { get; set; } 2:  3: public ReadOnlyCollection<KeyTitle> ReadonlyDictionary 4: { 5: get 6: { 7: return (from item in MyDictionary 8: select new KeyTitle 9: { 10: Key = item.Key, 11: Title = item.Value, 12: }).ToList().AsReadOnly(); 13: } 14: } Cool huh? Just one thing you need to know about the .AsReadOnly() method is that the only way to modify your ReadOnlyCollection<> is to modify the original collection. So doing: 1: public static void Main() 2: { 3: Class1 class1 = new Class1(); 4: class1.MyKeyTitleList.Add(new KeyTitle { Key = 1, Title = "abc" }); 5: class1.MyKeyTitleList.Add(new KeyTitle { Key = 2, Title = "def" }); 6: class1.MyKeyTitleList.Add(new KeyTitle { Key = 3, Title = "ghi" }); 7: class1.MyKeyTitleList.Add(new KeyTitle { Key = 4, Title = "jkl" }); 8: TryToModifyCollection(class1.MyKeyTitleList.AsReadOnly()); 9:  10: Console.WriteLine(); 11:  12: class1.MyKeyTitleList.Add(new KeyTitle { Key = 5, Title = "mno" }); 13: class1.MyKeyTitleList[2] = new KeyTitle{Key = 3, Title = "GHI"}; 14: TryToModifyCollection(class1.MyKeyTitleList.AsReadOnly()); 15:  16: Console.ReadLine(); 17: } Gives me the output of: See that the second element’s Title is changed to upper-case and the fifth element also gets displayed even though we’re still looping through the same ReadOnlyCollection<KeyTitle>. Verdict: Now you know of a way to implement ‘Method(const param1)’ in your code!

    Read the article

  • The practical cost of swapping effects

    - by sebf
    Hello, I use XNA for my projects and on those forums I sometimes see references to the fact that swapping an effect for a mesh has a relatively high cost, which surprises me as I thought to swap an effect was simply a case of copying the replacement shader program to the GPU along with appropriate parameters. I wondered if someone could explain exactly what is costly about this process? And put, if possible, 'relatively' into context? For example say I wanted to use a short shader to help with picking, I would: Change the effect on every object, calculting a unique color to identify it and providing it to the shader. Draw all the objects to a render target in memory. Get the color from the target and use it to look up the selected object. What portion of the total time taken to complete that process would be spent swapping the shaders? My instincts would say that rendering the scene again, no matter how simple the shader, would be an order of magnitude slower than any other part of the process so why all the concern over effects?

    Read the article

  • Updating a Progress Bar within the Status Bar [migrated]

    - by Muhnamana
    I'm trying to figure out how to incorporate a progress bar within the status bar to show how much processing is completed. Below is my example of updating the progress bar (not sure if this is the correct way or not) Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick ToolStripProgressBar1.Value = ToolStripProgressBar1.Value + 2 If ToolStripProgressBar1.Value = 100 Then ToolStripProgressBar1.Value = 0 ToolStripProgressBar1.Value = ToolStripProgressBar1.Value + 2 Timer1.Enabled = True End If End Sub Here is the code within the button. Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1Run.Click ToolStripStatusLabel1.Text = "Processing..." Timer1.Enabled = True 'more code to be inserted here End Sub What I'm not sure is how to update the progress bar based on the amount of code you have and once the processing is complete, update the ToolStripStatusLabel1 to show "Processing...Complete!".

    Read the article

  • Would like some help in understanding rendering geometry vs textures

    - by Anon
    So I was just pondering whether it is more taxing on the GPU to render geometry or a texture. What I'm trying to see is whether there is a huge difference in rendering two scenes with the same setup: Scene 1: Example Object: A dirt road (nothing else) Geometry: Detailed road, with all the bumps, cracks and so forth done in the mesh Scene 2: Example Object: A dirt road (nothing else) Geometry: A simple mesh, in a form of a road, but in this case maps and textures are simulating cracks, bumps, etc... So of these two, which one is likely to tax the hardware more? Or is it not a like for like comparison? What would be the best way of doing something like this? Go heavy on the textures? Or have a blend of both?

    Read the article

  • vector collision on polygon in 3d space detection/testing?

    - by LRFLEW
    In the 3d fps in java I'm working on, I need a bullet to be fired and to tell if it hit someone. All visual objects in the game are defined through OpenGL, so the object it can be colliding with can be any drawable polygon (although they will most likely be triangles and rectangles anyways). The bullet is not an object, but will be treated as a vector that instantaneously moves all the way across the map (like the snipper riffle in Halo). What's the best way to detect/test collisions with the polygon and the vector. I have access to OpenCL, however I have absolutely no experience with it. I am very early in the developmental stage, so if you think there's a better way of going about this, feel free to tell me (I barley have a player model to collide with anyways, so I'm flexible with it). Thanks

    Read the article

  • Circle-Rectangle collision in a tile map game

    - by furiousd
    I am making a 2D tile map based putt-putt game. I have collision detection working between the ball and the walls of the map, although when the ball collides at the meeting point between 2 tiles I offset it by 0.5 so that it doesn't get stuck in the wall. This aint a huge issue though. if(y % 20 == 0) { y+=0.5; } if(x % 20 == 0) { x+=0.5; } Collisions work as follows Find the closest point between each tile and the center of the ball If distance(ball_x, ball_y, close_x, close_y) <= ball_radius and the closest point belongs to a solid object, collision has occured Invert X/Y speed according to side of object collided with The next thing I tried to do was implement floating blocks in the middle of the map for the ball to bounce off of. When a ball collides with a corner of the block, it gets stuck in it. So I changed my determineRebound() function to treat corners as if they were circles. Here's that functon: `i and j are indexes of the solid object in the 2d map array. x & y are centre point of ball.` void determineRebound(int _i, int _j) { if(y > _i*tile_w && y < _i*tile_w + tile_w) { //Not a corner xs*=-1; } else if(x > _j*tile_w && x < _j*tile_w + tile_w) { //Not a corner ys*=-1; } else { //Corner float nx = x - close_x; float ny = y - close_y; float len = sqrt(nx * nx + ny * ny); nx /= len; ny /= len; float projection = xs * nx + ys * ny; xs -= 2 * projection * nx; ys -= 2 * projection * ny; } } This is where things have gotten messy. Collisions with 'floating' corners work fine, but now when the ball collides near the meeting point of 2 tiles, it detects a corner collision and does not rebound as expected. I'm a bit in over my head at this point. I guess I'm wondering if I'm going about making this sort of game in the right way. Is a 2d tile map the way to go? If so, is there a problem with my collision logic and where am I going wrong? Any advice/feedback would be great.

    Read the article

  • WCF web service with Neural Network

    - by Gary Frank
    I am developing a web service that performs object recognition. It will be available for testing as soon as enough code has been developed, and then officially when it is finished. It is based on a radically new type of artificial neural network that I designed. Its goal is to recognize any type of object within an image. Besides the WCF web service, the project will also create a website to test and demonstrate the web service. Here is a link with more information. http://www.indiegogo.com/VOR

    Read the article

  • Having a generic data type for a database table column, is it "good" practice?

    - by Yanick Rochon
    I'm working on a PHP project where some object (class member) may contain different data type. For example : class Property { private $_id; // (PK) private $_ref_id; // the object reference id (FK) private $_name; // the name of the property private $_type; // 'string', 'int', 'float(n,m)', 'datetime', etc. private $_data; // ... // ..snip.. public getters/setters } Now, I need to perform some persistence on these objects. Some properties may be a text data type, but nothing bigger than what a varchar may hold. Also, later on, I need to be able to perform searches and sorting. Is it a good practice to use a single database table for this (ie. is there a non negligible performance impact)? If it's "acceptable", then what could be the data type for the data column?

    Read the article

  • Why enumerator structs are a really bad idea (redux)

    - by Simon Cooper
    My previous blog post went into some detail as to why calling MoveNext on a BCL generic collection enumerator didn't quite do what you thought it would. This post covers the Reset method. To recap, here's the simple wrapper around a linked list enumerator struct from my previous post (minus the readonly on the enumerator variable): sealed class EnumeratorWrapper : IEnumerator<int> { private LinkedList<int>.Enumerator m_Enumerator; public EnumeratorWrapper(LinkedList<int> linkedList) { m_Enumerator = linkedList.GetEnumerator(); } public int Current { get { return m_Enumerator.Current; } } object System.Collections.IEnumerator.Current { get { return Current; } } public bool MoveNext() { return m_Enumerator.MoveNext(); } public void Reset() { ((System.Collections.IEnumerator)m_Enumerator).Reset(); } public void Dispose() { m_Enumerator.Dispose(); } } If you have a look at the Reset method, you'll notice I'm having to cast to IEnumerator to be able to call Reset on m_Enumerator. This is because the implementation of LinkedList<int>.Enumerator.Reset, and indeed of all the other Reset methods on the BCL generic collection enumerators, is an explicit interface implementation. However, IEnumerator is a reference type. LinkedList<int>.Enumerator is a value type. That means, in order to call the reset method at all, the enumerator has to be boxed. And the IL confirms this: .method public hidebysig newslot virtual final instance void Reset() cil managed { .maxstack 8 L_0000: nop L_0001: ldarg.0 L_0002: ldfld valuetype [System]System.Collections.Generic.LinkedList`1/Enumerator<int32> EnumeratorWrapper::m_Enumerator L_0007: box [System]System.Collections.Generic.LinkedList`1/Enumerator<int32> L_000c: callvirt instance void [mscorlib]System.Collections.IEnumerator::Reset() L_0011: nop L_0012: ret } On line 0007, we're doing a box operation, which copies the enumerator to a reference object on the heap, then on line 000c calling Reset on this boxed object. So m_Enumerator in the wrapper class is not modified by the call the Reset. And this is the only way to call the Reset method on this variable (without using reflection). Therefore, the only way that the collection enumerator struct can be used safely is to store them as a boxed IEnumerator<T>, and not use them as value types at all.

    Read the article

  • The performance implications of IEnumerable vs. IQueryable

    It all started innocently enough. I was implementing a "Older Posts/Newer Posts" feature for my new web site and was writing code like this:IEnumerable<Post> FilterByCategory(IEnumerable<Post> posts, string category) {  if( !string.IsNullOrEmpty(category) ) { return posts.Where(p => p.Category.Contains(category)); }}...  var posts = FilterByCategory(db.Posts, category);  int count = posts.Count();... The "db" was an EF object context object, but it could just as...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

  • The performance implications of IEnumerable vs. IQueryable

    It all started innocently enough. I was implementing a "Older Posts/Newer Posts" feature for my new web site and was writing code like this:IEnumerable<Post> FilterByCategory(IEnumerable<Post> posts, string category) {  if( !string.IsNullOrEmpty(category) ) { return posts.Where(p => p.Category.Contains(category)); }}...  var posts = FilterByCategory(db.Posts, category);  int count = posts.Count();... The "db" was an EF object context object, but it could just as...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

< Previous Page | 501 502 503 504 505 506 507 508 509 510 511 512  | Next Page >