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  • Reason why UIImage gives me a 'distorted' image sometimes

    - by Cedric Vandendriessche
    I have a custom UIView with a UILabel and a UIImageView subview. (tried using UIImageView subclass aswell). I assign an image to it and add the view to the screen. I wrote a function which adds the amount of LetterBoxes to the screen (my custom class): - (void)drawBoxesForWord:(NSString *)word { if(boxesContainer == nil) { /* Create a container for the LetterBoxes (animation purposes) */ boxesContainer = [[UIView alloc] initWithFrame:CGRectMake(0, 205, 320, 50)]; [self.view addSubview:boxesContainer]; } /* Calculate width of letterboxes */ NSInteger numberOfCharacters = [word length]; CGFloat totalWidth = numberOfCharacters * 28 + (numberOfCharacters - 1) * 3; CGFloat leftCap = (320 - totalWidth) / 2; [letters removeAllObjects]; /* Draw the boxes to the screen */ for (int i = 0; i < numberOfCharacters; i++) { LetterBox *letter = [[LetterBox alloc] initWithFrame:CGRectMake(leftCap + i * 31 , 0, 28, 40)]; [letters addObject:letter]; [boxesContainer addSubview:letter]; [letter release]; }} This gives me the image below: http://www.imgdumper.nl/uploads2/4ba3b2c72bb99/4ba3b2c72abfd-Goed.png But sometimes it gives me this: imgdumper.nl/uploads2/4ba3b2d888226/4ba3b2d88728a-Fout.png I add them to the same boxesContainer but they first remove themselves from the superview, so it's not like you see them double or something. What I find weird is that they are all good or all bad.. This is the init function for my LetterBox: if (self == [super initWithFrame:aRect]) { /* Create the box image with same frame */ boxImage = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height)]; boxImage.contentMode = UIViewContentModeScaleAspectFit; boxImage.image = [UIImage imageNamed:@"SpaceOpen.png"]; [self addSubview:boxImage]; /* Create the label with same frame */ letterLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height)]; letterLabel.backgroundColor = [UIColor clearColor]; letterLabel.font = [UIFont fontWithName:@"ArialRoundedMTBold" size:26]; letterLabel.textColor = [UIColor blackColor]; letterLabel.textAlignment = UITextAlignmentCenter; [self addSubview:letterLabel]; } return self;} Does anyone have an idea why this could be? I'd rather have them display correctly every time :)

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  • Parallelism in .NET – Part 5, Partitioning of Work

    - by Reed
    When parallelizing any routine, we start by decomposing the problem.  Once the problem is understood, we need to break our work into separate tasks, so each task can be run on a different processing element.  This process is called partitioning. Partitioning our tasks is a challenging feat.  There are opposing forces at work here: too many partitions adds overhead, too few partitions leaves processors idle.  Trying to work the perfect balance between the two extremes is the goal for which we should aim.  Luckily, the Task Parallel Library automatically handles much of this process.  However, there are situations where the default partitioning may not be appropriate, and knowledge of our routines may allow us to guide the framework to making better decisions. First off, I’d like to say that this is a more advanced topic.  It is perfectly acceptable to use the parallel constructs in the framework without considering the partitioning taking place.  The default behavior in the Task Parallel Library is very well-behaved, even for unusual work loads, and should rarely be adjusted.  I have found few situations where the default partitioning behavior in the TPL is not as good or better than my own hand-written partitioning routines, and recommend using the defaults unless there is a strong, measured, and profiled reason to avoid using them.  However, understanding partitioning, and how the TPL partitions your data, helps in understanding the proper usage of the TPL. I indirectly mentioned partitioning while discussing aggregation.  Typically, our systems will have a limited number of Processing Elements (PE), which is the terminology used for hardware capable of processing a stream of instructions.  For example, in a standard Intel i7 system, there are four processor cores, each of which has two potential hardware threads due to Hyperthreading.  This gives us a total of 8 PEs – theoretically, we can have up to eight operations occurring concurrently within our system. In order to fully exploit this power, we need to partition our work into Tasks.  A task is a simple set of instructions that can be run on a PE.  Ideally, we want to have at least one task per PE in the system, since fewer tasks means that some of our processing power will be sitting idle.  A naive implementation would be to just take our data, and partition it with one element in our collection being treated as one task.  When we loop through our collection in parallel, using this approach, we’d just process one item at a time, then reuse that thread to process the next, etc.  There’s a flaw in this approach, however.  It will tend to be slower than necessary, often slower than processing the data serially. The problem is that there is overhead associated with each task.  When we take a simple foreach loop body and implement it using the TPL, we add overhead.  First, we change the body from a simple statement to a delegate, which must be invoked.  In order to invoke the delegate on a separate thread, the delegate gets added to the ThreadPool’s current work queue, and the ThreadPool must pull this off the queue, assign it to a free thread, then execute it.  If our collection had one million elements, the overhead of trying to spawn one million tasks would destroy our performance. The answer, here, is to partition our collection into groups, and have each group of elements treated as a single task.  By adding a partitioning step, we can break our total work into small enough tasks to keep our processors busy, but large enough tasks to avoid overburdening the ThreadPool.  There are two clear, opposing goals here: Always try to keep each processor working, but also try to keep the individual partitions as large as possible. When using Parallel.For, the partitioning is always handled automatically.  At first, partitioning here seems simple.  A naive implementation would merely split the total element count up by the number of PEs in the system, and assign a chunk of data to each processor.  Many hand-written partitioning schemes work in this exactly manner.  This perfectly balanced, static partitioning scheme works very well if the amount of work is constant for each element.  However, this is rarely the case.  Often, the length of time required to process an element grows as we progress through the collection, especially if we’re doing numerical computations.  In this case, the first PEs will finish early, and sit idle waiting on the last chunks to finish.  Sometimes, work can decrease as we progress, since previous computations may be used to speed up later computations.  In this situation, the first chunks will be working far longer than the last chunks.  In order to balance the workload, many implementations create many small chunks, and reuse threads.  This adds overhead, but does provide better load balancing, which in turn improves performance. The Task Parallel Library handles this more elaborately.  Chunks are determined at runtime, and start small.  They grow slowly over time, getting larger and larger.  This tends to lead to a near optimum load balancing, even in odd cases such as increasing or decreasing workloads.  Parallel.ForEach is a bit more complicated, however. When working with a generic IEnumerable<T>, the number of items required for processing is not known in advance, and must be discovered at runtime.  In addition, since we don’t have direct access to each element, the scheduler must enumerate the collection to process it.  Since IEnumerable<T> is not thread safe, it must lock on elements as it enumerates, create temporary collections for each chunk to process, and schedule this out.  By default, it uses a partitioning method similar to the one described above.  We can see this directly by looking at the Visual Partitioning sample shipped by the Task Parallel Library team, and available as part of the Samples for Parallel Programming.  When we run the sample, with four cores and the default, Load Balancing partitioning scheme, we see this: The colored bands represent each processing core.  You can see that, when we started (at the top), we begin with very small bands of color.  As the routine progresses through the Parallel.ForEach, the chunks get larger and larger (seen by larger and larger stripes). Most of the time, this is fantastic behavior, and most likely will out perform any custom written partitioning.  However, if your routine is not scaling well, it may be due to a failure in the default partitioning to handle your specific case.  With prior knowledge about your work, it may be possible to partition data more meaningfully than the default Partitioner. There is the option to use an overload of Parallel.ForEach which takes a Partitioner<T> instance.  The Partitioner<T> class is an abstract class which allows for both static and dynamic partitioning.  By overriding Partitioner<T>.SupportsDynamicPartitions, you can specify whether a dynamic approach is available.  If not, your custom Partitioner<T> subclass would override GetPartitions(int), which returns a list of IEnumerator<T> instances.  These are then used by the Parallel class to split work up amongst processors.  When dynamic partitioning is available, GetDynamicPartitions() is used, which returns an IEnumerable<T> for each partition.  If you do decide to implement your own Partitioner<T>, keep in mind the goals and tradeoffs of different partitioning strategies, and design appropriately. The Samples for Parallel Programming project includes a ChunkPartitioner class in the ParallelExtensionsExtras project.  This provides example code for implementing your own, custom allocation strategies, including a static allocator of a given chunk size.  Although implementing your own Partitioner<T> is possible, as I mentioned above, this is rarely required or useful in practice.  The default behavior of the TPL is very good, often better than any hand written partitioning strategy.

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  • Dynamic Types and DynamicObject References in C#

    - by Rick Strahl
    I've been working a bit with C# custom dynamic types for several customers recently and I've seen some confusion in understanding how dynamic types are referenced. This discussion specifically centers around types that implement IDynamicMetaObjectProvider or subclass from DynamicObject as opposed to arbitrary type casts of standard .NET types. IDynamicMetaObjectProvider types  are treated special when they are cast to the dynamic type. Assume for a second that I've created my own implementation of a custom dynamic type called DynamicFoo which is about as simple of a dynamic class that I can think of:public class DynamicFoo : DynamicObject { Dictionary<string, object> properties = new Dictionary<string, object>(); public string Bar { get; set; } public DateTime Entered { get; set; } public override bool TryGetMember(GetMemberBinder binder, out object result) { result = null; if (!properties.ContainsKey(binder.Name)) return false; result = properties[binder.Name]; return true; } public override bool TrySetMember(SetMemberBinder binder, object value) { properties[binder.Name] = value; return true; } } This class has an internal dictionary member and I'm exposing this dictionary member through a dynamic by implementing DynamicObject. This implementation exposes the properties dictionary so the dictionary keys can be referenced like properties (foo.NewProperty = "Cool!"). I override TryGetMember() and TrySetMember() which are fired at runtime every time you access a 'property' on a dynamic instance of this DynamicFoo type. Strong Typing and Dynamic Casting I now can instantiate and use DynamicFoo in a couple of different ways: Strong TypingDynamicFoo fooExplicit = new DynamicFoo(); var fooVar = new DynamicFoo(); These two commands are essentially identical and use strong typing. The compiler generates identical code for both of them. The var statement is merely a compiler directive to infer the type of fooVar at compile time and so the type of fooExplicit is DynamicFoo, just like fooExplicit. This is very static - nothing dynamic about it - and it completely ignores the IDynamicMetaObjectProvider implementation of my class above as it's never used. Using either of these I can access the native properties:DynamicFoo fooExplicit = new DynamicFoo();// static typing assignmentsfooVar.Bar = "Barred!"; fooExplicit.Entered = DateTime.Now; // echo back static values Console.WriteLine(fooVar.Bar); Console.WriteLine(fooExplicit.Entered); but I have no access whatsoever to the properties dictionary. Basically this creates a strongly typed instance of the type with access only to the strongly typed interface. You get no dynamic behavior at all. The IDynamicMetaObjectProvider features don't kick in until you cast the type to dynamic. If I try to access a non-existing property on fooExplicit I get a compilation error that tells me that the property doesn't exist. Again, it's clearly and utterly non-dynamic. Dynamicdynamic fooDynamic = new DynamicFoo(); fooDynamic on the other hand is created as a dynamic type and it's a completely different beast. I can also create a dynamic by simply casting any type to dynamic like this:DynamicFoo fooExplicit = new DynamicFoo(); dynamic fooDynamic = fooExplicit; Note that dynamic typically doesn't require an explicit cast as the compiler automatically performs the cast so there's no need to use as dynamic. Dynamic functionality works at runtime and allows for the dynamic wrapper to look up and call members dynamically. A dynamic type will look for members to access or call in two places: Using the strongly typed members of the object Using theIDynamicMetaObjectProvider Interface methods to access members So rather than statically linking and calling a method or retrieving a property, the dynamic type looks up - at runtime  - where the value actually comes from. It's essentially late-binding which allows runtime determination what action to take when a member is accessed at runtime *if* the member you are accessing does not exist on the object. Class members are checked first before IDynamicMetaObjectProvider interface methods are kick in. All of the following works with the dynamic type:dynamic fooDynamic = new DynamicFoo(); // dynamic typing assignments fooDynamic.NewProperty = "Something new!"; fooDynamic.LastAccess = DateTime.Now; // dynamic assigning static properties fooDynamic.Bar = "dynamic barred"; fooDynamic.Entered = DateTime.Now; // echo back dynamic values Console.WriteLine(fooDynamic.NewProperty); Console.WriteLine(fooDynamic.LastAccess); Console.WriteLine(fooDynamic.Bar); Console.WriteLine(fooDynamic.Entered); The dynamic type can access the native class properties (Bar and Entered) and create and read new ones (NewProperty,LastAccess) all using a single type instance which is pretty cool. As you can see it's pretty easy to create an extensible type this way that can dynamically add members at runtime dynamically. The Alter Ego of IDynamicObject The key point here is that all three statements - explicit, var and dynamic - declare a new DynamicFoo(), but the dynamic declaration results in completely different behavior than the first two simply because the type has been cast to dynamic. Dynamic binding means that the type loses its typical strong typing, compile time features. You can see this easily in the Visual Studio code editor. As soon as you assign a value to a dynamic you lose Intellisense and you see which means there's no Intellisense and no compiler type checking on any members you apply to this instance. If you're new to the dynamic type it might seem really confusing that a single type can behave differently depending on how it is cast, but that's exactly what happens when you use a type that implements IDynamicMetaObjectProvider. Declare the type as its strong type name and you only get to access the native instance members of the type. Declare or cast it to dynamic and you get dynamic behavior which accesses native members plus it uses IDynamicMetaObjectProvider implementation to handle any missing member definitions by running custom code. You can easily cast objects back and forth between dynamic and the original type:dynamic fooDynamic = new DynamicFoo(); fooDynamic.NewProperty = "New Property Value"; DynamicFoo foo = fooDynamic; foo.Bar = "Barred"; Here the code starts out with a dynamic cast and a dynamic assignment. The code then casts back the value to the DynamicFoo. Notice that when casting from dynamic to DynamicFoo and back we typically do not have to specify the cast explicitly - the compiler can induce the type so I don't need to specify as dynamic or as DynamicFoo. Moral of the Story This easy interchange between dynamic and the underlying type is actually super useful, because it allows you to create extensible objects that can expose non-member data stores and expose them as an object interface. You can create an object that hosts a number of strongly typed properties and then cast the object to dynamic and add additional dynamic properties to the same type at runtime. You can easily switch back and forth between the strongly typed instance to access the well-known strongly typed properties and to dynamic for the dynamic properties added at runtime. Keep in mind that dynamic object access has quite a bit of overhead and is definitely slower than strongly typed binding, so if you're accessing the strongly typed parts of your objects you definitely want to use a strongly typed reference. Reserve dynamic for the dynamic members to optimize your code. The real beauty of dynamic is that with very little effort you can build expandable objects or objects that expose different data stores to an object interface. I'll have more on this in my next post when I create a customized and extensible Expando object based on DynamicObject.© Rick Strahl, West Wind Technologies, 2005-2012Posted in CSharp  .NET   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • C#/.NET Little Pitfalls: The Dangers of Casting Boxed Values

    - by James Michael Hare
    Starting a new series to parallel the Little Wonders series.  In this series, I will examine some of the small pitfalls that can occasionally trip up developers. Introduction: Of Casts and Conversions What happens when we try to assign from an int and a double and vice-versa? 1: double pi = 3.14; 2: int theAnswer = 42; 3:  4: // implicit widening conversion, compiles! 5: double doubleAnswer = theAnswer; 6:  7: // implicit narrowing conversion, compiler error! 8: int intPi = pi; As you can see from the comments above, a conversion from a value type where there is no potential data loss is can be done with an implicit conversion.  However, when converting from one value type to another may result in a loss of data, you must make the conversion explicit so the compiler knows you accept this risk.  That is why the conversion from double to int will not compile with an implicit conversion, we can make the conversion explicit by adding a cast: 1: // explicit narrowing conversion using a cast, compiler 2: // succeeds, but results may have data loss: 3: int intPi = (int)pi; So for value types, the conversions (implicit and explicit) both convert the original value to a new value of the given type.  With widening and narrowing references, however, this is not the case.  Converting reference types is a bit different from converting value types.  First of all when you perform a widening or narrowing you don’t really convert the instance of the object, you just convert the reference itself to the wider or narrower reference type, but both the original and new reference type both refer back to the same object. Secondly, widening and narrowing for reference types refers the going down and up the class hierarchy instead of referring to precision as in value types.  That is, a narrowing conversion for a reference type means you are going down the class hierarchy (for example from Shape to Square) whereas a widening conversion means you are going up the class hierarchy (from Square to Shape).  1: var square = new Square(); 2:  3: // implicitly convers because all squares are shapes 4: // (that is, all subclasses can be referenced by a superclass reference) 5: Shape myShape = square; 6:  7: // implicit conversion not possible, not all shapes are squares! 8: // (that is, not all superclasses can be referenced by a subclass reference) 9: Square mySquare = (Square) myShape; So we had to cast the Shape back to Square because at that point the compiler has no way of knowing until runtime whether the Shape in question is truly a Square.  But, because the compiler knows that it’s possible for a Shape to be a Square, it will compile.  However, if the object referenced by myShape is not truly a Square at runtime, you will get an invalid cast exception. Of course, there are other forms of conversions as well such as user-specified conversions and helper class conversions which are beyond the scope of this post.  The main thing we want to focus on is this seemingly innocuous casting method of widening and narrowing conversions that we come to depend on every day and, in some cases, can bite us if we don’t fully understand what is going on!  The Pitfall: Conversions on Boxed Value Types Can Fail What if you saw the following code and – knowing nothing else – you were asked if it was legal or not, what would you think: 1: // assuming x is defined above this and this 2: // assignment is syntactically legal. 3: x = 3.14; 4:  5: // convert 3.14 to int. 6: int truncated = (int)x; You may think that since x is obviously a double (can’t be a float) because 3.14 is a double literal, but this is inaccurate.  Our x could also be dynamic and this would work as well, or there could be user-defined conversions in play.  But there is another, even simpler option that can often bite us: what if x is object? 1: object x; 2:  3: x = 3.14; 4:  5: int truncated = (int) x; On the surface, this seems fine.  We have a double and we place it into an object which can be done implicitly through boxing (no cast) because all types inherit from object.  Then we cast it to int.  This theoretically should be possible because we know we can explicitly convert a double to an int through a conversion process which involves truncation. But here’s the pitfall: when casting an object to another type, we are casting a reference type, not a value type!  This means that it will attempt to see at runtime if the value boxed and referred to by x is of type int or derived from type int.  Since it obviously isn’t (it’s a double after all) we get an invalid cast exception! Now, you may say this looks awfully contrived, but in truth we can run into this a lot if we’re not careful.  Consider using an IDataReader to read from a database, and then attempting to select a result row of a particular column type: 1: using (var connection = new SqlConnection("some connection string")) 2: using (var command = new SqlCommand("select * from employee", connection)) 3: using (var reader = command.ExecuteReader()) 4: { 5: while (reader.Read()) 6: { 7: // if the salary is not an int32 in the SQL database, this is an error! 8: // doesn't matter if short, long, double, float, reader [] returns object! 9: total += (int) reader["annual_salary"]; 10: } 11: } Notice that since the reader indexer returns object, if we attempt to convert using a cast to a type, we have to make darn sure we use the true, actual type or this will fail!  If the SQL database column is a double, float, short, etc this will fail at runtime with an invalid cast exception because it attempts to convert the object reference! So, how do you get around this?  There are two ways, you could first cast the object to its actual type (double), and then do a narrowing cast to on the value to int.  Or you could use a helper class like Convert which analyzes the actual run-time type and will perform a conversion as long as the type implements IConvertible. 1: object x; 2:  3: x = 3.14; 4:  5: // if you want to cast, must cast out of object to double, then 6: // cast convert. 7: int truncated = (int)(double) x; 8:  9: // or you can call a helper class like Convert which examines runtime 10: // type of the value being converted 11: int anotherTruncated = Convert.ToInt32(x); Summary You should always be careful when performing a conversion cast from values boxed in object that you are actually casting to the true type (or a sub-type). Since casting from object is a widening of the reference, be careful that you either know the exact, explicit type you expect to be held in the object, or instead avoid the cast and use a helper class to perform a safe conversion to the type you desire. Technorati Tags: C#,.NET,Pitfalls,Little Pitfalls,BlackRabbitCoder

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  • Pluggable Rules for Entity Framework Code First

    - by Ricardo Peres
    Suppose you want a system that lets you plug custom validation rules on your Entity Framework context. The rules would control whether an entity can be saved, updated or deleted, and would be implemented in plain .NET. Yes, I know I already talked about plugable validation in Entity Framework Code First, but this is a different approach. An example API is in order, first, a ruleset, which will hold the collection of rules: 1: public interface IRuleset : IDisposable 2: { 3: void AddRule<T>(IRule<T> rule); 4: IEnumerable<IRule<T>> GetRules<T>(); 5: } Next, a rule: 1: public interface IRule<T> 2: { 3: Boolean CanSave(T entity, DbContext ctx); 4: Boolean CanUpdate(T entity, DbContext ctx); 5: Boolean CanDelete(T entity, DbContext ctx); 6: String Name 7: { 8: get; 9: } 10: } Let’s analyze what we have, starting with the ruleset: Only has methods for adding a rule, specific to an entity type, and to list all rules of this entity type; By implementing IDisposable, we allow it to be cancelled, by disposing of it when we no longer want its rules to be applied. A rule, on the other hand: Has discrete methods for checking if a given entity can be saved, updated or deleted, which receive as parameters the entity itself and a pointer to the DbContext to which the ruleset was applied; Has a name property for helping us identifying what failed. A ruleset really doesn’t need a public implementation, all we need is its interface. The private (internal) implementation might look like this: 1: sealed class Ruleset : IRuleset 2: { 3: private readonly IDictionary<Type, HashSet<Object>> rules = new Dictionary<Type, HashSet<Object>>(); 4: private ObjectContext octx = null; 5:  6: internal Ruleset(ObjectContext octx) 7: { 8: this.octx = octx; 9: } 10:  11: public void AddRule<T>(IRule<T> rule) 12: { 13: if (this.rules.ContainsKey(typeof(T)) == false) 14: { 15: this.rules[typeof(T)] = new HashSet<Object>(); 16: } 17:  18: this.rules[typeof(T)].Add(rule); 19: } 20:  21: public IEnumerable<IRule<T>> GetRules<T>() 22: { 23: if (this.rules.ContainsKey(typeof(T)) == true) 24: { 25: foreach (IRule<T> rule in this.rules[typeof(T)]) 26: { 27: yield return (rule); 28: } 29: } 30: } 31:  32: public void Dispose() 33: { 34: this.octx.SavingChanges -= RulesExtensions.OnSaving; 35: RulesExtensions.rulesets.Remove(this.octx); 36: this.octx = null; 37:  38: this.rules.Clear(); 39: } 40: } Basically, this implementation: Stores the ObjectContext of the DbContext to which it was created for, this is so that later we can remove the association; Has a collection - a set, actually, which does not allow duplication - of rules indexed by the real Type of an entity (because of proxying, an entity may be of a type that inherits from the class that we declared); Has generic methods for adding and enumerating rules of a given type; Has a Dispose method for cancelling the enforcement of the rules. A (really dumb) rule applied to Product might look like this: 1: class ProductRule : IRule<Product> 2: { 3: #region IRule<Product> Members 4:  5: public String Name 6: { 7: get 8: { 9: return ("Rule 1"); 10: } 11: } 12:  13: public Boolean CanSave(Product entity, DbContext ctx) 14: { 15: return (entity.Price > 10000); 16: } 17:  18: public Boolean CanUpdate(Product entity, DbContext ctx) 19: { 20: return (true); 21: } 22:  23: public Boolean CanDelete(Product entity, DbContext ctx) 24: { 25: return (true); 26: } 27:  28: #endregion 29: } The DbContext is there because we may need to check something else in the database before deciding whether to allow an operation or not. And here’s how to apply this mechanism to any DbContext, without requiring the usage of a subclass, by means of an extension method: 1: public static class RulesExtensions 2: { 3: private static readonly MethodInfo getRulesMethod = typeof(IRuleset).GetMethod("GetRules"); 4: internal static readonly IDictionary<ObjectContext, Tuple<IRuleset, DbContext>> rulesets = new Dictionary<ObjectContext, Tuple<IRuleset, DbContext>>(); 5:  6: private static Type GetRealType(Object entity) 7: { 8: return (entity.GetType().Assembly.IsDynamic == true ? entity.GetType().BaseType : entity.GetType()); 9: } 10:  11: internal static void OnSaving(Object sender, EventArgs e) 12: { 13: ObjectContext octx = sender as ObjectContext; 14: IRuleset ruleset = rulesets[octx].Item1; 15: DbContext ctx = rulesets[octx].Item2; 16:  17: foreach (ObjectStateEntry entry in octx.ObjectStateManager.GetObjectStateEntries(EntityState.Added)) 18: { 19: Object entity = entry.Entity; 20: Type realType = GetRealType(entity); 21:  22: foreach (dynamic rule in (getRulesMethod.MakeGenericMethod(realType).Invoke(ruleset, null) as IEnumerable)) 23: { 24: if (rule.CanSave(entity, ctx) == false) 25: { 26: throw (new Exception(String.Format("Cannot save entity {0} due to rule {1}", entity, rule.Name))); 27: } 28: } 29: } 30:  31: foreach (ObjectStateEntry entry in octx.ObjectStateManager.GetObjectStateEntries(EntityState.Deleted)) 32: { 33: Object entity = entry.Entity; 34: Type realType = GetRealType(entity); 35:  36: foreach (dynamic rule in (getRulesMethod.MakeGenericMethod(realType).Invoke(ruleset, null) as IEnumerable)) 37: { 38: if (rule.CanDelete(entity, ctx) == false) 39: { 40: throw (new Exception(String.Format("Cannot delete entity {0} due to rule {1}", entity, rule.Name))); 41: } 42: } 43: } 44:  45: foreach (ObjectStateEntry entry in octx.ObjectStateManager.GetObjectStateEntries(EntityState.Modified)) 46: { 47: Object entity = entry.Entity; 48: Type realType = GetRealType(entity); 49:  50: foreach (dynamic rule in (getRulesMethod.MakeGenericMethod(realType).Invoke(ruleset, null) as IEnumerable)) 51: { 52: if (rule.CanUpdate(entity, ctx) == false) 53: { 54: throw (new Exception(String.Format("Cannot update entity {0} due to rule {1}", entity, rule.Name))); 55: } 56: } 57: } 58: } 59:  60: public static IRuleset CreateRuleset(this DbContext context) 61: { 62: Tuple<IRuleset, DbContext> ruleset = null; 63: ObjectContext octx = (context as IObjectContextAdapter).ObjectContext; 64:  65: if (rulesets.TryGetValue(octx, out ruleset) == false) 66: { 67: ruleset = rulesets[octx] = new Tuple<IRuleset, DbContext>(new Ruleset(octx), context); 68: 69: octx.SavingChanges += OnSaving; 70: } 71:  72: return (ruleset.Item1); 73: } 74: } It relies on the SavingChanges event of the ObjectContext to intercept the saving operations before they are actually issued. Yes, it uses a bit of dynamic magic! Very handy, by the way! So, let’s put it all together: 1: using (MyContext ctx = new MyContext()) 2: { 3: IRuleset rules = ctx.CreateRuleset(); 4: rules.AddRule(new ProductRule()); 5:  6: ctx.Products.Add(new Product() { Name = "xyz", Price = 50000 }); 7:  8: ctx.SaveChanges(); //an exception is fired here 9:  10: //when we no longer need to apply the rules 11: rules.Dispose(); 12: } Feel free to use it and extend it any way you like, and do give me your feedback! As a final note, this can be easily changed to support plain old Entity Framework (not Code First, that is), if that is what you are using.

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  • "ID 046d:c50e Logitech, Inc. Cordless Mouse Receiver" wheel-click is wrong

    - by sputnick
    I use this mouse under archlinux x86_64 with 3.2.8-1-ARCH kernel. I have some problems to select and then paste with the wheel-click in some applications like konversation, not in a terminal nor an editor. I don't know if it's a hardware problem or a software one. $ lsusb -v Bus 002 Device 110: ID 046d:c50e Logitech, Inc. Cordless Mouse Receiver Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 0 (Defined at Interface level) bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 8 idVendor 0x046d Logitech, Inc. idProduct 0xc50e Cordless Mouse Receiver bcdDevice 25.10 iManufacturer 1 Logitech iProduct 2 USB RECEIVER iSerial 0 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 34 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xa0 (Bus Powered) Remote Wakeup MaxPower 70mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 1 bInterfaceClass 3 Human Interface Device bInterfaceSubClass 1 Boot Interface Subclass bInterfaceProtocol 2 Mouse iInterface 0 HID Device Descriptor: bLength 9 bDescriptorType 33 bcdHID 1.11 bCountryCode 0 Not supported bNumDescriptors 1 bDescriptorType 34 Report wDescriptorLength 95 Report Descriptors: ** UNAVAILABLE ** Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0008 1x 8 bytes bInterval 10 Device Status: 0x0000 (Bus Powered) When I see what's happens in xev, the output is different compared to another mouse My buggy Logitech mouse : ButtonPress event, serial 40, synthetic NO, window 0x4400001, root 0x15a, subw 0x4400002, time 170350700, (48,52), root:(1491,75), state 0x10, button 11, same_screen YES EnterNotify event, serial 40, synthetic NO, window 0x4400001, root 0x15a, subw 0x0, time 170350700, (48,52), root:(1491,75), mode NotifyGrab, detail NotifyInferior, same_screen YES, focus YES, state 16 KeymapNotify event, serial 40, synthetic NO, window 0x0, keys: 90 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ButtonPress event, serial 40, synthetic NO, window 0x4400001, root 0x15a, subw 0x4400002, time 170350716, (48,52), root:(1491,75), state 0x10, button 6, same_screen YES ButtonRelease event, serial 40, synthetic NO, window 0x4400001, root 0x15a, subw 0x4400002, time 170350716, (48,52), root:(1491,75), state 0x10, button 6, same_screen YES ButtonRelease event, serial 40, synthetic NO, window 0x4400001, root 0x15a, subw 0x4400002, time 170350988, (48,52), root:(1491,75), state 0x10, button 11, same_screen YES LeaveNotify event, serial 40, synthetic NO, window 0x4400001, root 0x15a, subw 0x0, time 170350988, (48,52), root:(1491,75), mode NotifyUngrab, detail NotifyInferior, same_screen YES, focus YES, state 16 a working mouse (dell) : ButtonPress event, serial 40, synthetic NO, window 0x4400001, root 0x15a, subw 0x4400002, time 170245131, (46,32), root:(1489,55), state 0x10, button 2, same_screen YES EnterNotify event, serial 40, synthetic NO, window 0x4400001, root 0x15a, subw 0x0, time 170245131, (46,32), root:(1489,55), mode NotifyGrab, detail NotifyInferior, same_screen YES, focus YES, state 528 KeymapNotify event, serial 40, synthetic NO, window 0x0, keys: 90 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ButtonRelease event, serial 40, synthetic NO, window 0x4400001, root 0x15a, subw 0x4400002, time 170245411, (46,32), root:(1489,55), state 0x210, button 2, same_screen YES LeaveNotify event, serial 40, synthetic NO, window 0x4400001, root 0x15a, subw 0x0, time 170245411, (46,32), root:(1489,55), mode NotifyUngrab, detail NotifyInferior, same_screen YES, focus YES, state 16 A demo of the problem when I use konversation (IRC) : http://www.youtube.com/watch?v=lhmr92M7NCc I tried to modify the button map with xmodmap like this with no success (one at a time) : xmodmap -e "pointer = 1 0 3" xmodmap -e "pointer = 1 1 3" xmodmap -e "pointer = 1 2 3" xmodmap -e "pointer = 1 3 3" xmodmap -e "pointer = 1 4 3" xmodmap -e "pointer = 1 5 3" xmodmap -e "pointer = 1 6 3" xmodmap -e "pointer = 1 7 3" xmodmap -e "pointer = 1 8 3" xmodmap -e "pointer = 1 9 3" xmodmap -e "pointer = 1 10 3" xmodmap -e "pointer = 1 11 3" xmodmap -e "pointer = 1 12 3" xmodmap -e "pointer = 1 13 3" xmodmap -e "pointer = 1 14 3" xmodmap -e "pointer = 1 15 3" xmodmap -e "pointer = 1 16 3" xmodmap -e "pointer = 1 17 3" xmodmap -e "pointer = 1 18 3" xmodmap -e "pointer = 1 19 3" xmodmap -e "pointer = 1 20 3" xmodmap -e "pointer = 1 21 3" xmodmap -e "pointer = 1 22 3" xmodmap -e "pointer = 1 23 3" xmodmap -e "pointer = 1 24 3" xmodmap -e "pointer = 1 25 3" Any clue ? I would like to avoid buying a new mouse just for a paste problem.

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  • Login loop in Snow Leopard

    - by hgpc
    I can't get out of a login loop of a particular admin user. After entering the password the login screen is shown again after about a minute. Other users work fine. It started happening after a simple reboot. Can you please help me? Thank you! Tried to no avail: Change the password Remove the password Repair disk (no errors) Boot in safe mode Reinstall Snow Leopard and updating to 10.6.6 Remove content of ~/Library/Caches Removed content of ~/Library/Preferences Replaced /etc/authorization with Install DVD copy The system.log mentions a crash report. I'm including both below. system.log Jan 8 02:43:30 loginwindow218: Login Window - Returned from Security Agent Jan 8 02:43:30 loginwindow218: USER_PROCESS: 218 console Jan 8 02:44:42 kernel[0]: Jan 8 02:44:43: --- last message repeated 1 time --- Jan 8 02:44:43 com.apple.launchd[1] (com.apple.loginwindow218): Job appears to have crashed: Bus error Jan 8 02:44:43 com.apple.UserEventAgent-LoginWindow223: ALF error: cannot find useragent 1102 Jan 8 02:44:43 com.apple.UserEventAgent-LoginWindow223: plugin.UserEventAgentFactory: called with typeID=FC86416D-6164-2070-726F-70735C216EC0 Jan 8 02:44:43 /System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow233: Login Window Application Started Jan 8 02:44:43 SecurityAgent228: CGSShutdownServerConnections: Detaching application from window server Jan 8 02:44:43 com.apple.ReportCrash.Root232: 2011-01-08 02:44:43.936 ReportCrash232:2903 Saved crash report for loginwindow218 version ??? (???) to /Library/Logs/DiagnosticReports/loginwindow_2011-01-08-024443_localhost.crash Jan 8 02:44:44 SecurityAgent228: MIG: server died: CGSReleaseShmem : Cannot release shared memory Jan 8 02:44:44 SecurityAgent228: kCGErrorFailure: Set a breakpoint @ CGErrorBreakpoint() to catch errors as they are logged. Jan 8 02:44:44 SecurityAgent228: CGSDisplayServerShutdown: Detaching display subsystem from window server Jan 8 02:44:44 SecurityAgent228: HIToolbox: received notification of WindowServer event port death. Jan 8 02:44:44 SecurityAgent228: port matched the WindowServer port created in BindCGSToRunLoop Jan 8 02:44:44 loginwindow233: Login Window Started Security Agent Jan 8 02:44:44 WindowServer234: kCGErrorFailure: Set a breakpoint @ CGErrorBreakpoint() to catch errors as they are logged. Jan 8 02:44:44 com.apple.WindowServer234: Sat Jan 8 02:44:44 .local WindowServer234 <Error>: kCGErrorFailure: Set a breakpoint @ CGErrorBreakpoint() to catch errors as they are logged. Jan 8 02:44:54 SecurityAgent243: NSSecureTextFieldCell detected a field editor ((null)) that is not a NSTextView subclass designed to work with the cell. Ignoring... Crash report Process: loginwindow 218 Path: /System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow Identifier: loginwindow Version: ??? (???) Code Type: X86-64 (Native) Parent Process: launchd [1] Date/Time: 2011-01-08 02:44:42.748 +0100 OS Version: Mac OS X 10.6.6 (10J567) Report Version: 6 Exception Type: EXC_BAD_ACCESS (SIGBUS) Exception Codes: 0x000000000000000a, 0x000000010075b000 Crashed Thread: 0 Dispatch queue: com.apple.main-thread Thread 0 Crashed: Dispatch queue: com.apple.main-thread 0 com.apple.security 0x00007fff801c6e8b Security::ReadSection::at(unsigned int) const + 25 1 com.apple.security 0x00007fff801c632f Security::DbVersion::open() + 123 2 com.apple.security 0x00007fff801c5e41 Security::DbVersion::DbVersion(Security::AppleDatabase const&, Security::RefPointer<Security::AtomicBufferedFile> const&) + 179 3 com.apple.security 0x00007fff801c594e Security::DbModifier::getDbVersion(bool) + 330 4 com.apple.security 0x00007fff801c57f5 Security::DbModifier::openDatabase() + 33 5 com.apple.security 0x00007fff801c5439 Security::Database::_dbOpen(Security::DatabaseSession&, unsigned int, Security::AccessCredentials const*, void const*) + 221 6 com.apple.security 0x00007fff801c4841 Security::DatabaseManager::dbOpen(Security::DatabaseSession&, Security::DbName const&, unsigned int, Security::AccessCredentials const*, void const*) + 77 7 com.apple.security 0x00007fff801c4723 Security::DatabaseSession::DbOpen(char const*, cssm_net_address const*, unsigned int, Security::AccessCredentials const*, void const*, long&) + 285 8 com.apple.security 0x00007fff801d8414 cssm_DbOpen(long, char const*, cssm_net_address const*, unsigned int, cssm_access_credentials const*, void const*, long*) + 108 9 com.apple.security 0x00007fff801d7fba CSSM_DL_DbOpen + 106 10 com.apple.security 0x00007fff801d62f6 Security::CssmClient::DbImpl::open() + 162 11 com.apple.security 0x00007fff801d8977 SSDatabaseImpl::open(Security::DLDbIdentifier const&) + 53 12 com.apple.security 0x00007fff801d8715 SSDLSession::DbOpen(char const*, cssm_net_address const*, unsigned int, Security::AccessCredentials const*, void const*, long&) + 263 13 com.apple.security 0x00007fff801d8414 cssm_DbOpen(long, char const*, cssm_net_address const*, unsigned int, cssm_access_credentials const*, void const*, long*) + 108 14 com.apple.security 0x00007fff801d7fba CSSM_DL_DbOpen + 106 15 com.apple.security 0x00007fff801d62f6 Security::CssmClient::DbImpl::open() + 162 16 com.apple.security 0x00007fff802fa786 Security::CssmClient::DbImpl::unlock(cssm_data const&) + 28 17 com.apple.security 0x00007fff80275b5d Security::KeychainCore::KeychainImpl::unlock(Security::CssmData const&) + 89 18 com.apple.security 0x00007fff80291a06 Security::KeychainCore::StorageManager::login(unsigned int, void const*, unsigned int, void const*) + 3336 19 com.apple.security 0x00007fff802854d3 SecKeychainLogin + 91 20 com.apple.loginwindow 0x000000010000dfc5 0x100000000 + 57285 21 com.apple.loginwindow 0x000000010000cfb4 0x100000000 + 53172 22 com.apple.Foundation 0x00007fff8721e44f __NSThreadPerformPerform + 219 23 com.apple.CoreFoundation 0x00007fff82627401 __CFRunLoopDoSources0 + 1361 24 com.apple.CoreFoundation 0x00007fff826255f9 __CFRunLoopRun + 873 25 com.apple.CoreFoundation 0x00007fff82624dbf CFRunLoopRunSpecific + 575 26 com.apple.HIToolbox 0x00007fff8444493a RunCurrentEventLoopInMode + 333 27 com.apple.HIToolbox 0x00007fff8444473f ReceiveNextEventCommon + 310 28 com.apple.HIToolbox 0x00007fff844445f8 BlockUntilNextEventMatchingListInMode + 59 29 com.apple.AppKit 0x00007fff80b01e64 _DPSNextEvent + 718 30 com.apple.AppKit 0x00007fff80b017a9 -NSApplication nextEventMatchingMask:untilDate:inMode:dequeue: + 155 31 com.apple.AppKit 0x00007fff80ac748b -NSApplication run + 395 32 com.apple.loginwindow 0x0000000100004b16 0x100000000 + 19222 33 com.apple.loginwindow 0x0000000100004580 0x100000000 + 17792 Thread 1: Dispatch queue: com.apple.libdispatch-manager 0 libSystem.B.dylib 0x00007fff8755216a kevent + 10 1 libSystem.B.dylib 0x00007fff8755403d _dispatch_mgr_invoke + 154 2 libSystem.B.dylib 0x00007fff87553d14 _dispatch_queue_invoke + 185 3 libSystem.B.dylib 0x00007fff8755383e _dispatch_worker_thread2 + 252 4 libSystem.B.dylib 0x00007fff87553168 _pthread_wqthread + 353 5 libSystem.B.dylib 0x00007fff87553005 start_wqthread + 13 Thread 0 crashed with X86 Thread State (64-bit): rax: 0x000000010075b000 rbx: 0x00007fff5fbfd990 rcx: 0x00007fff875439da rdx: 0x0000000000000000 rdi: 0x00007fff5fbfd990 rsi: 0x0000000000000000 rbp: 0x00007fff5fbfd5d0 rsp: 0x00007fff5fbfd5d0 r8: 0x0000000000000007 r9: 0x0000000000000000 r10: 0x00007fff8753beda r11: 0x0000000000000202 r12: 0x0000000100133e78 r13: 0x00007fff5fbfda50 r14: 0x00007fff5fbfda50 r15: 0x00007fff5fbfdaa0 rip: 0x00007fff801c6e8b rfl: 0x0000000000010287 cr2: 0x000000010075b000

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  • Creating a Dynamic DataRow for easier DataRow Syntax

    - by Rick Strahl
    I've been thrown back into an older project that uses DataSets and DataRows as their entity storage model. I have several applications internally that I still maintain that run just fine (and I sometimes wonder if this wasn't easier than all this ORM crap we deal with with 'newer' improved technology today - but I disgress) but use this older code. For the most part DataSets/DataTables/DataRows are abstracted away in a pseudo entity model, but in some situations like queries DataTables and DataRows are still surfaced to the business layer. Here's an example. Here's a business object method that runs dynamic query and the code ends up looping over the result set using the ugly DataRow Array syntax:public int UpdateAllSafeTitles() { int result = this.Execute("select pk, title, safetitle from " + Tablename + " where EntryType=1", "TPks"); if (result < 0) return result; result = 0; foreach (DataRow row in this.DataSet.Tables["TPks"].Rows) { string title = row["title"] as string; string safeTitle = row["safeTitle"] as string; int pk = (int)row["pk"]; string newSafeTitle = this.GetSafeTitle(title); if (newSafeTitle != safeTitle) { this.ExecuteNonQuery("update " + this.Tablename + " set safeTitle=@safeTitle where pk=@pk", this.CreateParameter("@safeTitle",newSafeTitle), this.CreateParameter("@pk",pk) ); result++; } } return result; } The problem with looping over DataRow objecs is two fold: The array syntax is tedious to type and not real clear to look at, and explicit casting is required in order to do anything useful with the values. I've highlighted the place where this matters. Using the DynamicDataRow class I'll show in a minute this code can be changed to look like this:public int UpdateAllSafeTitles() { int result = this.Execute("select pk, title, safetitle from " + Tablename + " where EntryType=1", "TPks"); if (result < 0) return result; result = 0; foreach (DataRow row in this.DataSet.Tables["TPks"].Rows) { dynamic entry = new DynamicDataRow(row); string newSafeTitle = this.GetSafeTitle(entry.title); if (newSafeTitle != entry.safeTitle) { this.ExecuteNonQuery("update " + this.Tablename + " set safeTitle=@safeTitle where pk=@pk", this.CreateParameter("@safeTitle",newSafeTitle), this.CreateParameter("@pk",entry.pk) ); result++; } } return result; } The code looks much a bit more natural and describes what's happening a little nicer as well. Well, using the new dynamic features in .NET it's actually quite easy to implement the DynamicDataRow class. Creating your own custom Dynamic Objects .NET 4.0 introduced the Dynamic Language Runtime (DLR) and opened up a whole bunch of new capabilities for .NET applications. The dynamic type is an easy way to avoid Reflection and directly access members of 'dynamic' or 'late bound' objects at runtime. There's a lot of very subtle but extremely useful stuff that dynamic does (especially for COM Interop scenearios) but in its simplest form it often allows you to do away with manual Reflection at runtime. In addition you can create DynamicObject implementations that can perform  custom interception of member accesses and so allow you to provide more natural access to more complex or awkward data structures like the DataRow that I use as an example here. Bascially you can subclass DynamicObject and then implement a few methods (TryGetMember, TrySetMember, TryInvokeMember) to provide the ability to return dynamic results from just about any data structure using simple property/method access. In the code above, I created a custom DynamicDataRow class which inherits from DynamicObject and implements only TryGetMember and TrySetMember. Here's what simple class looks like:/// <summary> /// This class provides an easy way to turn a DataRow /// into a Dynamic object that supports direct property /// access to the DataRow fields. /// /// The class also automatically fixes up DbNull values /// (null into .NET and DbNUll to DataRow) /// </summary> public class DynamicDataRow : DynamicObject { /// <summary> /// Instance of object passed in /// </summary> DataRow DataRow; /// <summary> /// Pass in a DataRow to work off /// </summary> /// <param name="instance"></param> public DynamicDataRow(DataRow dataRow) { DataRow = dataRow; } /// <summary> /// Returns a value from a DataRow items array. /// If the field doesn't exist null is returned. /// DbNull values are turned into .NET nulls. /// /// </summary> /// <param name="binder"></param> /// <param name="result"></param> /// <returns></returns> public override bool TryGetMember(GetMemberBinder binder, out object result) { result = null; try { result = DataRow[binder.Name]; if (result == DBNull.Value) result = null; return true; } catch { } result = null; return false; } /// <summary> /// Property setter implementation tries to retrieve value from instance /// first then into this object /// </summary> /// <param name="binder"></param> /// <param name="value"></param> /// <returns></returns> public override bool TrySetMember(SetMemberBinder binder, object value) { try { if (value == null) value = DBNull.Value; DataRow[binder.Name] = value; return true; } catch {} return false; } } To demonstrate the basic features here's a short test: [TestMethod] [ExpectedException(typeof(RuntimeBinderException))] public void BasicDataRowTests() { DataTable table = new DataTable("table"); table.Columns.Add( new DataColumn() { ColumnName = "Name", DataType=typeof(string) }); table.Columns.Add( new DataColumn() { ColumnName = "Entered", DataType=typeof(DateTime) }); table.Columns.Add(new DataColumn() { ColumnName = "NullValue", DataType = typeof(string) }); DataRow row = table.NewRow(); DateTime now = DateTime.Now; row["Name"] = "Rick"; row["Entered"] = now; row["NullValue"] = null; // converted in DbNull dynamic drow = new DynamicDataRow(row); string name = drow.Name; DateTime entered = drow.Entered; string nulled = drow.NullValue; Assert.AreEqual(name, "Rick"); Assert.AreEqual(entered,now); Assert.IsNull(nulled); // this should throw a RuntimeBinderException Assert.AreEqual(entered,drow.enteredd); } The DynamicDataRow requires a custom constructor that accepts a single parameter that sets the DataRow. Once that's done you can access property values that match the field names. Note that types are automatically converted - no type casting is needed in the code you write. The class also automatically converts DbNulls to regular nulls and vice versa which is something that makes it much easier to deal with data returned from a database. What's cool here isn't so much the functionality - even if I'd prefer to leave DataRow behind ASAP -  but the fact that we can create a dynamic type that uses a DataRow as it's 'DataSource' to serve member values. It's pretty useful feature if you think about it, especially given how little code it takes to implement. By implementing these two simple methods we get to provide two features I was complaining about at the beginning that are missing from the DataRow: Direct Property Syntax Automatic Type Casting so no explicit casts are required Caveats As cool and easy as this functionality is, it's important to understand that it doesn't come for free. The dynamic features in .NET are - well - dynamic. Which means they are essentially evaluated at runtime (late bound). Rather than static typing where everything is compiled and linked by the compiler/linker, member invokations are looked up at runtime and essentially call into your custom code. There's some overhead in this. Direct invocations - the original code I showed - is going to be faster than the equivalent dynamic code. However, in the above code the difference of running the dynamic code and the original data access code was very minor. The loop running over 1500 result records took on average 13ms with the original code and 14ms with the dynamic code. Not exactly a serious performance bottleneck. One thing to remember is that Microsoft optimized the DLR code significantly so that repeated calls to the same operations are routed very efficiently which actually makes for very fast evaluation. The bottom line for performance with dynamic code is: Make sure you test and profile your code if you think that there might be a performance issue. However, in my experience with dynamic types so far performance is pretty good for repeated operations (ie. in loops). While usually a little slower the perf hit is a lot less typically than equivalent Reflection work. Although the code in the second example looks like standard object syntax, dynamic is not static code. It's evaluated at runtime and so there's no type recognition until runtime. This means no Intellisense at development time, and any invalid references that call into 'properties' (ie. fields in the DataRow) that don't exist still cause runtime errors. So in the case of the data row you still get a runtime error if you mistype a column name:// this should throw a RuntimeBinderException Assert.AreEqual(entered,drow.enteredd); Dynamic - Lots of uses The arrival of Dynamic types in .NET has been met with mixed emotions. Die hard .NET developers decry dynamic types as an abomination to the language. After all what dynamic accomplishes goes against all that a static language is supposed to provide. On the other hand there are clearly scenarios when dynamic can make life much easier (COM Interop being one place). Think of the possibilities. What other data structures would you like to expose to a simple property interface rather than some sort of collection or dictionary? And beyond what I showed here you can also implement 'Method missing' behavior on objects with InvokeMember which essentially allows you to create dynamic methods. It's all very flexible and maybe just as important: It's easy to do. There's a lot of power hidden in this seemingly simple interface. Your move…© Rick Strahl, West Wind Technologies, 2005-2011Posted in CSharp  .NET   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • C#: Adding Functionality to 3rd Party Libraries With Extension Methods

    - by James Michael Hare
    Ever have one of those third party libraries that you love but it's missing that one feature or one piece of syntactical candy that would make it so much more useful?  This, I truly think, is one of the best uses of extension methods.  I began discussing extension methods in my last post (which you find here) where I expounded upon what I thought were some rules of thumb for using extension methods correctly.  As long as you keep in line with those (or similar) rules, they can often be useful for adding that little extra functionality or syntactical simplification for a library that you have little or no control over. Oh sure, you could take an open source project, download the source and add the methods you want, but then every time the library is updated you have to re-add your changes, which can be cumbersome and error prone.  And yes, you could possibly extend a class in a third party library and override features, but that's only if the class is not sealed, static, or constructed via factories. This is the perfect place to use an extension method!  And the best part is, you and your development team don't need to change anything!  Simply add the using for the namespace the extensions are in! So let's consider this example.  I love log4net!  Of all the logging libraries I've played with, it, to me, is one of the most flexible and configurable logging libraries and it performs great.  But this isn't about log4net, well, not directly.  So why would I want to add functionality?  Well, it's missing one thing I really want in the ILog interface: ability to specify logging level at runtime. For example, let's say I declare my ILog instance like so:     using log4net;     public class LoggingTest     {         private static readonly ILog _log = LogManager.GetLogger(typeof(LoggingTest));         ...     }     If you don't know log4net, the details aren't important, just to show that the field _log is the logger I have gotten from log4net. So now that I have that, I can log to it like so:     _log.Debug("This is the lowest level of logging and just for debugging output.");     _log.Info("This is an informational message.  Usual normal operation events.");     _log.Warn("This is a warning, something suspect but not necessarily wrong.");     _log.Error("This is an error, some sort of processing problem has happened.");     _log.Fatal("Fatals usually indicate the program is dying hideously."); And there's many flavors of each of these to log using string formatting, to log exceptions, etc.  But one thing there isn't: the ability to easily choose the logging level at runtime.  Notice, the logging levels above are chosen at compile time.  Of course, you could do some fun stuff with lambdas and wrap it, but that would obscure the simplicity of the interface.  And yes there is a Logger property you can dive down into where you can specify a Level, but the Level properties don't really match the ILog interface exactly and then you have to manually build a LogEvent and... well, it gets messy.  I want something simple and sexy so I can say:     _log.Log(someLevel, "This will be logged at whatever level I choose at runtime!");     Now, some purists out there might say you should always know what level you want to log at, and for the most part I agree with them.  For the most party the ILog interface satisfies 99% of my needs.  In fact, for most application logging yes you do always know the level you will be logging at, but when writing a utility class, you may not always know what level your user wants. I'll tell you, one of my favorite things is to write reusable components.  If I had my druthers I'd write framework libraries and shared components all day!  And being able to easily log at a runtime-chosen level is a big need for me.  After all, if I want my code to really be re-usable, I shouldn't force a user to deal with the logging level I choose. One of my favorite uses for this is in Interceptors -- I'll describe Interceptors in my next post and some of my favorites -- for now just know that an Interceptor wraps a class and allows you to add functionality to an existing method without changing it's signature.  At the risk of over-simplifying, it's a very generic implementation of the Decorator design pattern. So, say for example that you were writing an Interceptor that would time method calls and emit a log message if the method call execution time took beyond a certain threshold of time.  For instance, maybe if your database calls take more than 5,000 ms, you want to log a warning.  Or if a web method call takes over 1,000 ms, you want to log an informational message.  This would be an excellent use of logging at a generic level. So here was my personal wish-list of requirements for my task: Be able to determine if a runtime-specified logging level is enabled. Be able to log generically at a runtime-specified logging level. Have the same look-and-feel of the existing Debug, Info, Warn, Error, and Fatal calls.    Having the ability to also determine if logging for a level is on at runtime is also important so you don't spend time building a potentially expensive logging message if that level is off.  Consider an Interceptor that may log parameters on entrance to the method.  If you choose to log those parameter at DEBUG level and if DEBUG is not on, you don't want to spend the time serializing those parameters. Now, mine may not be the most elegant solution, but it performs really well since the enum I provide all uses contiguous values -- while it's never guaranteed, contiguous switch values usually get compiled into a jump table in IL which is VERY performant - O(1) - but even if it doesn't, it's still so fast you'd never need to worry about it. So first, I need a way to let users pass in logging levels.  Sure, log4net has a Level class, but it's a class with static members and plus it provides way too many options compared to ILog interface itself -- and wouldn't perform as well in my level-check -- so I define an enum like below.     namespace Shared.Logging.Extensions     {         // enum to specify available logging levels.         public enum LoggingLevel         {             Debug,             Informational,             Warning,             Error,             Fatal         }     } Now, once I have this, writing the extension methods I need is trivial.  Once again, I would typically /// comment fully, but I'm eliminating for blogging brevity:     namespace Shared.Logging.Extensions     {         // the extension methods to add functionality to the ILog interface         public static class LogExtensions         {             // Determines if logging is enabled at a given level.             public static bool IsLogEnabled(this ILog logger, LoggingLevel level)             {                 switch (level)                 {                     case LoggingLevel.Debug:                         return logger.IsDebugEnabled;                     case LoggingLevel.Informational:                         return logger.IsInfoEnabled;                     case LoggingLevel.Warning:                         return logger.IsWarnEnabled;                     case LoggingLevel.Error:                         return logger.IsErrorEnabled;                     case LoggingLevel.Fatal:                         return logger.IsFatalEnabled;                 }                                 return false;             }             // Logs a simple message - uses same signature except adds LoggingLevel             public static void Log(this ILog logger, LoggingLevel level, object message)             {                 switch (level)                 {                     case LoggingLevel.Debug:                         logger.Debug(message);                         break;                     case LoggingLevel.Informational:                         logger.Info(message);                         break;                     case LoggingLevel.Warning:                         logger.Warn(message);                         break;                     case LoggingLevel.Error:                         logger.Error(message);                         break;                     case LoggingLevel.Fatal:                         logger.Fatal(message);                         break;                 }             }             // Logs a message and exception to the log at specified level.             public static void Log(this ILog logger, LoggingLevel level, object message, Exception exception)             {                 switch (level)                 {                     case LoggingLevel.Debug:                         logger.Debug(message, exception);                         break;                     case LoggingLevel.Informational:                         logger.Info(message, exception);                         break;                     case LoggingLevel.Warning:                         logger.Warn(message, exception);                         break;                     case LoggingLevel.Error:                         logger.Error(message, exception);                         break;                     case LoggingLevel.Fatal:                         logger.Fatal(message, exception);                         break;                 }             }             // Logs a formatted message to the log at the specified level.              public static void LogFormat(this ILog logger, LoggingLevel level, string format,                                          params object[] args)             {                 switch (level)                 {                     case LoggingLevel.Debug:                         logger.DebugFormat(format, args);                         break;                     case LoggingLevel.Informational:                         logger.InfoFormat(format, args);                         break;                     case LoggingLevel.Warning:                         logger.WarnFormat(format, args);                         break;                     case LoggingLevel.Error:                         logger.ErrorFormat(format, args);                         break;                     case LoggingLevel.Fatal:                         logger.FatalFormat(format, args);                         break;                 }             }         }     } So there it is!  I didn't have to modify the log4net source code, so if a new version comes out, i can just add the new assembly with no changes.  I didn't have to subclass and worry about developers not calling my sub-class instead of the original.  I simply provide the extension methods and it's as if the long lost extension methods were always a part of the ILog interface! Consider a very contrived example using the original interface:     // using the original ILog interface     public class DatabaseUtility     {         private static readonly ILog _log = LogManager.Create(typeof(DatabaseUtility));                 // some theoretical method to time         IDataReader Execute(string statement)         {             var timer = new System.Diagnostics.Stopwatch();                         // do DB magic                                    // this is hard-coded to warn, if want to change at runtime tough luck!             if (timer.ElapsedMilliseconds > 5000 && _log.IsWarnEnabled)             {                 _log.WarnFormat("Statement {0} took too long to execute.", statement);             }             ...         }     }     Now consider this alternate call where the logging level could be perhaps a property of the class          // using the original ILog interface     public class DatabaseUtility     {         private static readonly ILog _log = LogManager.Create(typeof(DatabaseUtility));                 // allow logging level to be specified by user of class instead         public LoggingLevel ThresholdLogLevel { get; set; }                 // some theoretical method to time         IDataReader Execute(string statement)         {             var timer = new System.Diagnostics.Stopwatch();                         // do DB magic                                    // this is hard-coded to warn, if want to change at runtime tough luck!             if (timer.ElapsedMilliseconds > 5000 && _log.IsLogEnabled(ThresholdLogLevel))             {                 _log.LogFormat(ThresholdLogLevel, "Statement {0} took too long to execute.",                     statement);             }             ...         }     } Next time, I'll show one of my favorite uses for these extension methods in an Interceptor.

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  • How to get objects to react to touches in Cocos2D?

    - by Wayfarer
    Alright, so I'm starting to learn more about Coco2D, but I'm kinda frusterated. A lot of the tutorials I have found are for outdated versions of the code, so when I look through and see how they do certain things, I can't translate it into my own program, because a lot has changed. With that being said, I am working in the latest version of Coco2d, version 0.99. What I want to do is create a sprite on the screen (Done) and then when I touch that sprite, I can have "something" happen. For now, let's just make an alert go off. Now, I got this code working with the help of a friend. Here is the header file: // When you import this file, you import all the cocos2d classes #import "cocos2d.h" // HelloWorld Layer @interface HelloWorld : CCLayer { CGRect spRect; } // returns a Scene that contains the HelloWorld as the only child +(id) scene; @end And here is the implementation file: // // cocos2d Hello World example // http://www.cocos2d-iphone.org // // Import the interfaces #import "HelloWorldScene.h" #import "CustomCCNode.h" // HelloWorld implementation @implementation HelloWorld +(id) scene { // 'scene' is an autorelease object. CCScene *scene = [CCScene node]; // 'layer' is an autorelease object. HelloWorld *layer = [HelloWorld node]; // add layer as a child to scene [scene addChild: layer]; // return the scene return scene; } // on "init" you need to initialize your instance -(id) init { // always call "super" init // Apple recommends to re-assign "self" with the "super" return value if( (self=[super init] )) { // create and initialize a Label CCLabel* label = [CCLabel labelWithString:@"Hello World" fontName:@"Times New Roman" fontSize:64]; // ask director the the window size CGSize size = [[CCDirector sharedDirector] winSize]; // position the label on the center of the screen label.position = ccp( size.width /2 , size.height/2 ); // add the label as a child to this Layer [self addChild: label]; CCSprite *sp = [CCSprite spriteWithFile:@"test2.png"]; sp.position = ccp(300,200); [self addChild:sp]; float w = [sp contentSize].width; float h = [sp contentSize].height; CGPoint aPoint = CGPointMake([sp position].x - (w/2), [sp position].y - (h/2)); spRect = CGRectMake(aPoint.x, aPoint.y, w, h); CCSprite *sprite2 = [CCSprite spriteWithFile:@"test3.png"]; sprite2.position = ccp(100,100); [self addChild:sprite2]; //[self registerWithTouchDispatcher]; self.isTouchEnabled = YES; } return self; } // on "dealloc" you need to release all your retained objects - (void) dealloc { // in case you have something to dealloc, do it in this method // in this particular example nothing needs to be released. // cocos2d will automatically release all the children (Label) // don't forget to call "super dealloc" [super dealloc]; } - (void)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; //CGPoint location = [[CCDirector sharedDirector] convertCoordinate:[touch locationInView:touch.view]]; CGPoint location = [touch locationInView:[touch view]]; location = [[CCDirector sharedDirector] convertToGL:location]; if (CGRectContainsPoint(spRect, location)) { UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Win" message:@"testing" delegate:nil cancelButtonTitle:@"okay" otherButtonTitles:nil]; [alert show]; [alert release]; NSLog(@"TOUCHES"); } NSLog(@"Touch got"); } However, this only works for 1 object, the sprite which I create the CGRect for. I can't do it for 2 sprites, which I was testing. So my question is this: How can I have all sprites on the screen react to the same event when touched? For my program, the same event needs to be run for all objects of the same type, so that should make it a tad easier. I tried making a subclass of CCNode and over write the method, but that just didn't work at all... so I'm doing something wrong. Help would be appreciated!

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  • C#/.NET Little Wonders: The EventHandler and EventHandler&lt;TEventArgs&gt; delegates

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. In the last two weeks, we examined the Action family of delegates (and delegates in general), and the Func family of delegates and how they can be used to support generic, reusable algorithms and classes. So this week, we are going to look at a handy pair of delegates that can be used to eliminate the need for defining custom delegates when creating events: the EventHandler and EventHandler<TEventArgs> delegates. Events and delegates Before we begin, let’s quickly consider events in .NET.  According to the MSDN: An event in C# is a way for a class to provide notifications to clients of that class when some interesting thing happens to an object. So, basically, you can create an event in a type so that users of that type can subscribe to notifications of things of interest.  How is this different than some of the delegate programming that we talked about in the last two weeks?  Well, you can think of an event as a special access modifier on a delegate.  Some differences between the two are: Events are a special access case of delegates They behave much like delegates instances inside the type they are declared in, but outside of that type they can only be (un)subscribed to. Events can specify add/remove behavior explicitly If you want to do additional work when someone subscribes or unsubscribes to an event, you can specify the add and remove actions explicitly. Events have access modifiers, but these only specify the access level of those who can (un)subscribe A public event, for example, means anyone can (un)subscribe, but it does not mean that anyone can raise (invoke) the event directly.  Events can only be raised by the type that contains them In contrast, if a delegate is visible, it can be invoked outside of the object (not even in a sub-class!). Events tend to be for notifications only, and should be treated as optional Semantically speaking, events typically don’t perform work on the the class directly, but tend to just notify subscribers when something of note occurs. My basic rule-of-thumb is that if you are just wanting to notify any listeners (who may or may not care) that something has happened, use an event.  However, if you want the caller to provide some function to perform to direct the class about how it should perform work, make it a delegate. Declaring events using custom delegates To declare an event in a type, we simply use the event keyword and specify its delegate type.  For example, let’s say you wanted to create a new TimeOfDayTimer that triggers at a given time of the day (as opposed to on an interval).  We could write something like this: 1: public delegate void TimeOfDayHandler(object source, ElapsedEventArgs e); 2:  3: // A timer that will fire at time of day each day. 4: public class TimeOfDayTimer : IDisposable 5: { 6: // Event that is triggered at time of day. 7: public event TimeOfDayHandler Elapsed; 8:  9: // ... 10: } The first thing to note is that the event is a delegate type, which tells us what types of methods may subscribe to it.  The second thing to note is the signature of the event handler delegate, according to the MSDN: The standard signature of an event handler delegate defines a method that does not return a value, whose first parameter is of type Object and refers to the instance that raises the event, and whose second parameter is derived from type EventArgs and holds the event data. If the event does not generate event data, the second parameter is simply an instance of EventArgs. Otherwise, the second parameter is a custom type derived from EventArgs and supplies any fields or properties needed to hold the event data. So, in a nutshell, the event handler delegates should return void and take two parameters: An object reference to the object that raised the event. An EventArgs (or a subclass of EventArgs) reference to event specific information. Even if your event has no additional information to provide, you are still expected to provide an EventArgs instance.  In this case, feel free to pass the EventArgs.Empty singleton instead of creating new instances of EventArgs (to avoid generating unneeded memory garbage). The EventHandler delegate Because many events have no additional information to pass, and thus do not require custom EventArgs, the signature of the delegates for subscribing to these events is typically: 1: // always takes an object and an EventArgs reference 2: public delegate void EventHandler(object sender, EventArgs e) It would be insane to recreate this delegate for every class that had a basic event with no additional event data, so there already exists a delegate for you called EventHandler that has this very definition!  Feel free to use it to define any events which supply no additional event information: 1: public class Cache 2: { 3: // event that is raised whenever the cache performs a cleanup 4: public event EventHandler OnCleanup; 5:  6: // ... 7: } This will handle any event with the standard EventArgs (no additional information).  But what of events that do need to supply additional information?  Does that mean we’re out of luck for subclasses of EventArgs?  That’s where the generic for of EventHandler comes into play… The generic EventHandler<TEventArgs> delegate Starting with the introduction of generics in .NET 2.0, we have a generic delegate called EventHandler<TEventArgs>.  Its signature is as follows: 1: public delegate void EventHandler<TEventArgs>(object sender, TEventArgs e) 2: where TEventArgs : EventArgs This is similar to EventHandler except it has been made generic to support the more general case.  Thus, it will work for any delegate where the first argument is an object (the sender) and the second argument is a class derived from EventArgs (the event data). For example, let’s say we wanted to create a message receiver, and we wanted it to have a few events such as OnConnected that will tell us when a connection is established (probably with no additional information) and OnMessageReceived that will tell us when a new message arrives (probably with a string for the new message text). So for OnMessageReceived, our MessageReceivedEventArgs might look like this: 1: public sealed class MessageReceivedEventArgs : EventArgs 2: { 3: public string Message { get; set; } 4: } And since OnConnected needs no event argument type defined, our class might look something like this: 1: public class MessageReceiver 2: { 3: // event that is called when the receiver connects with sender 4: public event EventHandler OnConnected; 5:  6: // event that is called when a new message is received. 7: public event EventHandler<MessageReceivedEventArgs> OnMessageReceived; 8:  9: // ... 10: } Notice, nowhere did we have to define a delegate to fit our event definition, the EventHandler and generic EventHandler<TEventArgs> delegates fit almost anything we’d need to do with events. Sidebar: Thread-safety and raising an event When the time comes to raise an event, we should always check to make sure there are subscribers, and then only raise the event if anyone is subscribed.  This is important because if no one is subscribed to the event, then the instance will be null and we will get a NullReferenceException if we attempt to raise the event. 1: // This protects against NullReferenceException... or does it? 2: if (OnMessageReceived != null) 3: { 4: OnMessageReceived(this, new MessageReceivedEventArgs(aMessage)); 5: } The above code seems to handle the null reference if no one is subscribed, but there’s a problem if this is being used in multi-threaded environments.  For example, assume we have thread A which is about to raise the event, and it checks and clears the null check and is about to raise the event.  However, before it can do that thread B unsubscribes to the event, which sets the delegate to null.  Now, when thread A attempts to raise the event, this causes the NullReferenceException that we were hoping to avoid! To counter this, the simplest best-practice method is to copy the event (just a multicast delegate) to a temporary local variable just before we raise it.  Since we are inside the class where this event is being raised, we can copy it to a local variable like this, and it will protect us from multi-threading since multicast delegates are immutable and assignments are atomic: 1: // always make copy of the event multi-cast delegate before checking 2: // for null to avoid race-condition between the null-check and raising it. 3: var handler = OnMessageReceived; 4: 5: if (handler != null) 6: { 7: handler(this, new MessageReceivedEventArgs(aMessage)); 8: } The very slight trade-off is that it’s possible a class may get an event after it unsubscribes in a multi-threaded environment, but this is a small risk and classes should be prepared for this possibility anyway.  For a more detailed discussion on this, check out this excellent Eric Lippert blog post on Events and Races. Summary Generic delegates give us a lot of power to make generic algorithms and classes, and the EventHandler delegate family gives us the flexibility to create events easily, without needing to redefine delegates over and over.  Use them whenever you need to define events with or without specialized EventArgs.   Tweet Technorati Tags: .NET, C#, CSharp, Little Wonders, Generics, Delegates, EventHandler

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  • New Bundling and Minification Support (ASP.NET 4.5 Series)

    - by ScottGu
    This is the sixth in a series of blog posts I'm doing on ASP.NET 4.5. The next release of .NET and Visual Studio include a ton of great new features and capabilities.  With ASP.NET 4.5 you'll see a bunch of really nice improvements with both Web Forms and MVC - as well as in the core ASP.NET base foundation that both are built upon. Today’s post covers some of the work we are doing to add built-in support for bundling and minification into ASP.NET - which makes it easy to improve the performance of applications.  This feature can be used by all ASP.NET applications, including both ASP.NET MVC and ASP.NET Web Forms solutions. Basics of Bundling and Minification As more and more people use mobile devices to surf the web, it is becoming increasingly important that the websites and apps we build perform well with them. We’ve all tried loading sites on our smartphones – only to eventually give up in frustration as it loads slowly over a slow cellular network.  If your site/app loads slowly like that, you are likely losing potential customers because of bad performance.  Even with powerful desktop machines, the load time of your site and perceived performance can make an enormous customer perception. Most websites today are made up of multiple JavaScript and CSS files to separate the concerns and keep the code base tight. While this is a good practice from a coding point of view, it often has some unfortunate consequences for the overall performance of the website.  Multiple JavaScript and CSS files require multiple HTTP requests from a browser – which in turn can slow down the performance load time.  Simple Example Below I’ve opened a local website in IE9 and recorded the network traffic using IE’s built-in F12 developer tools. As shown below, the website consists of 5 CSS and 4 JavaScript files which the browser has to download. Each file is currently requested separately by the browser and returned by the server, and the process can take a significant amount of time proportional to the number of files in question. Bundling ASP.NET is adding a feature that makes it easy to “bundle” or “combine” multiple CSS and JavaScript files into fewer HTTP requests. This causes the browser to request a lot fewer files and in turn reduces the time it takes to fetch them.   Below is an updated version of the above sample that takes advantage of this new bundling functionality (making only one request for the JavaScript and one request for the CSS): The browser now has to send fewer requests to the server. The content of the individual files have been bundled/combined into the same response, but the content of the files remains the same - so the overall file size is exactly the same as before the bundling.   But notice how even on a local dev machine (where the network latency between the browser and server is minimal), the act of bundling the CSS and JavaScript files together still manages to reduce the overall page load time by almost 20%.  Over a slow network the performance improvement would be even better. Minification The next release of ASP.NET is also adding a new feature that makes it easy to reduce or “minify” the download size of the content as well.  This is a process that removes whitespace, comments and other unneeded characters from both CSS and JavaScript. The result is smaller files, which will download and load in a browser faster.  The graph below shows the performance gain we are seeing when both bundling and minification are used together: Even on my local dev box (where the network latency is minimal), we now have a 40% performance improvement from where we originally started.  On slow networks (and especially with international customers), the gains would be even more significant. Using Bundling and Minification inside ASP.NET The upcoming release of ASP.NET makes it really easy to take advantage of bundling and minification within projects and see performance gains like in the scenario above. The way it does this allows you to avoid having to run custom tools as part of your build process –  instead ASP.NET has added runtime support to perform the bundling/minification for you dynamically (caching the results to make sure perf is great).  This enables a really clean development experience and makes it super easy to start to take advantage of these new features. Let’s assume that we have a simple project that has 4 JavaScript files and 6 CSS files: Bundling and Minifying the .css files Let’s say you wanted to reference all of the stylesheets in the “Styles” folder above on a page.  Today you’d have to add multiple CSS references to get all of them – which would translate into 6 separate HTTP requests: The new bundling/minification feature now allows you to instead bundle and minify all of the .css files in the Styles folder – simply by sending a URL request to the folder (in this case “styles”) with an appended “/css” path after it.  For example:    This will cause ASP.NET to scan the directory, bundle and minify the .css files within it, and send back a single HTTP response with all of the CSS content to the browser.  You don’t need to run any tools or pre-processor to get this behavior.  This enables you to cleanly separate your CSS into separate logical .css files and maintain a very clean development experience – while not taking a performance hit at runtime for doing so.  The Visual Studio designer will also honor the new bundling/minification logic as well – so you’ll still get a WYSWIYG designer experience inside VS as well. Bundling and Minifying the JavaScript files Like the CSS approach above, if we wanted to bundle and minify all of our JavaScript into a single response we could send a URL request to the folder (in this case “scripts”) with an appended “/js” path after it:   This will cause ASP.NET to scan the directory, bundle and minify the .js files within it, and send back a single HTTP response with all of the JavaScript content to the browser.  Again – no custom tools or builds steps were required in order to get this behavior.  And it works with all browsers. Ordering of Files within a Bundle By default, when files are bundled by ASP.NET they are sorted alphabetically first, just like they are shown in Solution Explorer. Then they are automatically shifted around so that known libraries and their custom extensions such as jQuery, MooTools and Dojo are loaded before anything else. So the default order for the merged bundling of the Scripts folder as shown above will be: Jquery-1.6.2.js Jquery-ui.js Jquery.tools.js a.js By default, CSS files are also sorted alphabetically and then shifted around so that reset.css and normalize.css (if they are there) will go before any other file. So the default sorting of the bundling of the Styles folder as shown above will be: reset.css content.css forms.css globals.css menu.css styles.css The sorting is fully customizable, though, and can easily be changed to accommodate most use cases and any common naming pattern you prefer.  The goal with the out of the box experience, though, is to have smart defaults that you can just use and be successful with. Any number of directories/sub-directories supported In the example above we just had a single “Scripts” and “Styles” folder for our application.  This works for some application types (e.g. single page applications).  Often, though, you’ll want to have multiple CSS/JS bundles within your application – for example: a “common” bundle that has core JS and CSS files that all pages use, and then page specific or section specific files that are not used globally. You can use the bundling/minification support across any number of directories or sub-directories in your project – this makes it easy to structure your code so as to maximize the bunding/minification benefits.  Each directory by default can be accessed as a separate URL addressable bundle.  Bundling/Minification Extensibility ASP.NET’s bundling and minification support is built with extensibility in mind and every part of the process can be extended or replaced. Custom Rules In addition to enabling the out of the box - directory-based - bundling approach, ASP.NET also supports the ability to register custom bundles using a new programmatic API we are exposing.  The below code demonstrates how you can register a “customscript” bundle using code within an application’s Global.asax class.  The API allows you to add/remove/filter files that go into the bundle on a very granular level:     The above custom bundle can then be referenced anywhere within the application using the below <script> reference:     Custom Processing You can also override the default CSS and JavaScript bundles to support your own custom processing of the bundled files (for example: custom minification rules, support for Saas, LESS or Coffeescript syntax, etc). In the example below we are indicating that we want to replace the built-in minification transforms with a custom MyJsTransform and MyCssTransform class. They both subclass the CSS and JavaScript minifier respectively and can add extra functionality:     The end result of this extensibility is that you can plug-into the bundling/minification logic at a deep level and do some pretty cool things with it. 2 Minute Video of Bundling and Minification in Action Mads Kristensen has a great 90 second video that shows off using the new Bundling and Minification feature.  You can watch the 90 second video here. Summary The new bundling and minification support within the next release of ASP.NET will make it easier to build fast web applications.  It is really easy to use, and doesn’t require major changes to your existing dev workflow.  It is also supports a rich extensibility API that enables you to customize it however you want. You can easily take advantage of this new support within ASP.NET MVC, ASP.NET Web Forms and ASP.NET Web Pages based applications. Hope this helps, Scott P.S. In addition to blogging, I use Twitter to-do quick posts and share links. My Twitter handle is: @scottgu

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  • Is there a Generic USB TouchScreen Driver 12.04?

    - by lbjoum
    Is there a Generic USB TouchScreen Driver 12.04? Device 03eb:201c I've been looking for 4 days solid (not very skilled) and can't find a solution. I have a generic tablet: C97- Atom N2600 9.7" 2GB 32GB Bluetooth WiFi WebCam Ext.3G Windows 7 Tablet PC Using 12.04 and cannot find a driver. I installed android and the touchscreen works but still lots of other bugs. Oh well, stuck with Windows 7 and not happy about it. Will keep trying, but too much time wasted already. If you have a solution I would love to try it. ubuntu@ubuntu:~$ lsusb Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 002: ID 0cf2:6238 ENE Technology, Inc. Bus 001 Device 003: ID 1a40:0101 Terminus Technology Inc. 4-Port HUB Bus 001 Device 005: ID 05e1:0100 Syntek Semiconductor Co., Ltd 802.11g + Bluetooth Wireless Adapter Bus 001 Device 006: ID 090c:3731 Silicon Motion, Inc. - Taiwan (formerly Feiya Technology Corp.) Bus 003 Device 002: ID 03eb:201c Atmel Corp. at90usbkey sample firmware (HID mouse) (from Windows: HID\VID_03EB&PID_201C\6&5F38127&0&0000 USB\VID_03EB&PID_201C\5&193ADADC&1&2 ) Bus 001 Device 007: ID 0518:0001 EzKEY Corp. USB to PS2 Adaptor v1.09 Bus 001 Device 008: ID 192f:0916 Avago Technologies, Pte. ubuntu@ubuntu:~$ sudo lsusb -v Bus 003 Device 002: ID 03eb:201c Atmel Corp. at90usbkey sample firmware (HID mouse) Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.00 bDeviceClass 0 (Defined at Interface level) bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 32 idVendor 0x03eb Atmel Corp. idProduct 0x201c at90usbkey sample firmware (HID mouse) bcdDevice 45.a2 iManufacturer 1 CDT iProduct 2 9.75 iSerial 0 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 34 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0x00 (Missing must-be-set bit!) (Bus Powered) MaxPower 100mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 1 bInterfaceClass 3 Human Interface Device bInterfaceSubClass 0 No Subclass bInterfaceProtocol 0 None iInterface 0 HID Device Descriptor: bLength 9 bDescriptorType 33 bcdHID 1.11 bCountryCode 0 Not supported bNumDescriptors 1 bDescriptorType 34 Report wDescriptorLength 177 Report Descriptors: ** UNAVAILABLE ** Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0020 1x 32 bytes bInterval 5 Device Status: 0x00fb Self Powered Remote Wakeup Enabled Debug Mode ubuntu@ubuntu:~$ sudo lshw ubuntu description: Notebook product: To be filled by O.E.M. (To be filled by O.E.M.) vendor: To be filled by O.E.M. version: To be filled by O.E.M. serial: To be filled by O.E.M. width: 32 bits capabilities: smbios-2.7 dmi-2.7 smp-1.4 smp configuration: boot=normal chassis=notebook cpus=2 family=To be filled by O.E.M. sku=To be filled by O.E.M. uuid=00020003-0004-0005-0006-000700080009 *-core description: Motherboard product: Tiger Hill vendor: INTEL Corporation physical id: 0 version: To be filled by O.E.M. serial: To be filled by O.E.M. slot: To be filled by O.E.M. *-firmware description: BIOS vendor: American Megatrends Inc. physical id: 0 version: 4.6.5 date: 08/24/2012 size: 64KiB capacity: 960KiB capabilities: pci upgrade shadowing cdboot bootselect socketedrom edd int13floppy1200 int13floppy720 int13floppy2880 int5printscreen int9keyboard int14serial int17printer acpi usb biosbootspecification *-cpu:0 description: CPU product: Intel(R) Atom(TM) CPU N2600 @ 1.60GHz vendor: Intel Corp. physical id: 4 bus info: cpu@0 version: 6.6.1 serial: 0003-0661-0000-0000-0000-0000 slot: CPU 1 size: 1600MHz capacity: 1600MHz width: 64 bits clock: 400MHz capabilities: x86-64 boot fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc arch_perfmon pebs bts nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm movbe lahf_lm arat configuration: cores=2 enabledcores=1 id=2 threads=2 *-cache:0 description: L1 cache physical id: 5 slot: L1-Cache size: 24KiB capacity: 24KiB capabilities: internal write-back unified *-cache:1 description: L2 cache physical id: 6 slot: L2-Cache size: 512KiB capacity: 512KiB capabilities: internal varies unified *-logicalcpu:0 description: Logical CPU physical id: 2.1 width: 64 bits capabilities: logical *-logicalcpu:1 description: Logical CPU physical id: 2.2 width: 64 bits capabilities: logical *-logicalcpu:2 description: Logical CPU physical id: 2.3 width: 64 bits capabilities: logical *-logicalcpu:3 description: Logical CPU physical id: 2.4 width: 64 bits capabilities: logical *-memory description: System Memory physical id: 28 slot: System board or motherboard size: 2GiB *-bank:0 description: SODIMM [empty] product: [Empty] vendor: [Empty] physical id: 0 serial: [Empty] slot: DIMM0 *-bank:1 description: SODIMM DDR3 Synchronous 800 MHz (1.2 ns) vendor: 69 physical id: 1 serial: 00000210 slot: DIMM1 size: 2GiB width: 64 bits clock: 800MHz (1.2ns) *-cpu:1 physical id: 1 bus info: cpu@1 version: 6.6.1 serial: 0003-0661-0000-0000-0000-0000 size: 1600MHz capabilities: ht configuration: id=2 *-logicalcpu:0 description: Logical CPU physical id: 2.1 capabilities: logical *-logicalcpu:1 description: Logical CPU physical id: 2.2 capabilities: logical *-logicalcpu:2 description: Logical CPU physical id: 2.3 capabilities: logical *-logicalcpu:3 description: Logical CPU physical id: 2.4 capabilities: logical *-pci description: Host bridge product: Atom Processor D2xxx/N2xxx DRAM Controller vendor: Intel Corporation physical id: 100 bus info: pci@0000:00:00.0 version: 03 width: 32 bits clock: 33MHz *-display UNCLAIMED description: VGA compatible controller product: Atom Processor D2xxx/N2xxx Integrated Graphics Controller vendor: Intel Corporation physical id: 2 bus info: pci@0000:00:02.0 version: 09 width: 32 bits clock: 33MHz capabilities: pm msi vga_controller bus_master cap_list configuration: latency=0 resources: memory:dfe00000-dfefffff ioport:f100(size=8) *-multimedia description: Audio device product: N10/ICH 7 Family High Definition Audio Controller vendor: Intel Corporation physical id: 1b bus info: pci@0000:00:1b.0 version: 02 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:42 memory:dff00000-dff03fff *-pci:0 description: PCI bridge product: N10/ICH 7 Family PCI Express Port 1 vendor: Intel Corporation physical id: 1c bus info: pci@0000:00:1c.0 version: 02 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:40 ioport:2000(size=4096) memory:80000000-801fffff ioport:80200000(size=2097152) *-usb:0 description: USB controller product: N10/ICH 7 Family USB UHCI Controller #1 vendor: Intel Corporation physical id: 1d bus info: pci@0000:00:1d.0 version: 02 width: 32 bits clock: 33MHz capabilities: uhci bus_master configuration: driver=uhci_hcd latency=0 resources: irq:23 ioport:f0a0(size=32) *-usb:1 description: USB controller product: N10/ICH 7 Family USB UHCI Controller #2 vendor: Intel Corporation physical id: 1d.1 bus info: pci@0000:00:1d.1 version: 02 width: 32 bits clock: 33MHz capabilities: uhci bus_master configuration: driver=uhci_hcd latency=0 resources: irq:19 ioport:f080(size=32) *-usb:2 description: USB controller product: N10/ICH 7 Family USB UHCI Controller #3 vendor: Intel Corporation physical id: 1d.2 bus info: pci@0000:00:1d.2 version: 02 width: 32 bits clock: 33MHz capabilities: uhci bus_master configuration: driver=uhci_hcd latency=0 resources: irq:18 ioport:f060(size=32) *-usb:3 description: USB controller product: N10/ICH 7 Family USB UHCI Controller #4 vendor: Intel Corporation physical id: 1d.3 bus info: pci@0000:00:1d.3 version: 02 width: 32 bits clock: 33MHz capabilities: uhci bus_master configuration: driver=uhci_hcd latency=0 resources: irq:16 ioport:f040(size=32) *-usb:4 description: USB controller product: N10/ICH 7 Family USB2 EHCI Controller vendor: Intel Corporation physical id: 1d.7 bus info: pci@0000:00:1d.7 version: 02 width: 32 bits clock: 33MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci_hcd latency=0 resources: irq:23 memory:dff05000-dff053ff *-pci:1 description: PCI bridge product: 82801 Mobile PCI Bridge vendor: Intel Corporation physical id: 1e bus info: pci@0000:00:1e.0 version: e2 width: 32 bits clock: 33MHz capabilities: pci subtractive_decode bus_master cap_list *-isa description: ISA bridge product: NM10 Family LPC Controller vendor: Intel Corporation physical id: 1f bus info: pci@0000:00:1f.0 version: 02 width: 32 bits clock: 33MHz capabilities: isa bus_master cap_list configuration: latency=0 *-storage description: SATA controller product: N10/ICH7 Family SATA Controller [AHCI mode] vendor: Intel Corporation physical id: 1f.2 bus info: pci@0000:00:1f.2 logical name: scsi0 version: 02 width: 32 bits clock: 66MHz capabilities: storage msi pm ahci_1.0 bus_master cap_list emulated configuration: driver=ahci latency=0 resources: irq:41 ioport:f0f0(size=8) ioport:f0e0(size=4) ioport:f0d0(size=8) ioport:f0c0(size=4) ioport:f020(size=16) memory:dff04000-dff043ff *-disk description: ATA Disk product: BIWIN SSD physical id: 0.0.0 bus info: scsi@0:0.0.0 logical name: /dev/sda version: 1206 serial: 123403501060 size: 29GiB (32GB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 signature=8fbe402b *-volume:0 description: Windows NTFS volume physical id: 1 bus info: scsi@0:0.0.0,1 logical name: /dev/sda1 version: 3.1 serial: 249bde5d-8246-9a40-88c7-2d5e3bcaf692 size: 19GiB capacity: 19GiB capabilities: primary bootable ntfs initialized configuration: clustersize=4096 created=2011-04-04 02:27:51 filesystem=ntfs state=clean *-volume:1 description: Windows NTFS volume physical id: 2 bus info: scsi@0:0.0.0,2 logical name: /dev/sda2 version: 3.1 serial: de12d40f-d5ca-8642-b306-acd9349fda1a size: 10231MiB capacity: 10GiB capabilities: primary ntfs initialized configuration: clustersize=4096 created=2011-04-04 01:52:26 filesystem=ntfs state=clean *-serial UNCLAIMED description: SMBus product: N10/ICH 7 Family SMBus Controller vendor: Intel Corporation physical id: 1f.3 bus info: pci@0000:00:1f.3 version: 02 width: 32 bits clock: 33MHz configuration: latency=0 resources: ioport:f000(size=32) *-scsi:0 physical id: 2 bus info: usb@1:1 logical name: scsi4 capabilities: emulated scsi-host configuration: driver=usb-storage *-disk description: SCSI Disk physical id: 0.0.0 bus info: scsi@4:0.0.0 logical name: /dev/sdb size: 29GiB (31GB) capabilities: partitioned partitioned:dos configuration: signature=00017463 *-volume description: Windows FAT volume vendor: mkdosfs physical id: 1 bus info: scsi@4:0.0.0,1 logical name: /dev/sdb1 logical name: /cdrom version: FAT32 serial: 129b-4f87 size: 29GiB capacity: 29GiB capabilities: primary bootable fat initialized configuration: FATs=2 filesystem=fat mount.fstype=vfat mount.options=rw,relatime,fmask=0022,dmask=0022,codepage=cp437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro state=mounted *-scsi:1 physical id: 3 bus info: usb@1:3.1 logical name: scsi6 capabilities: emulated scsi-host configuration: driver=usb-storage *-disk description: SCSI Disk physical id: 0.0.0 bus info: scsi@6:0.0.0 logical name: /dev/sdc size: 7400MiB (7759MB) capabilities: partitioned partitioned:dos configuration: signature=c3072e18 *-volume description: Windows FAT volume vendor: mkdosfs physical id: 1 bus info: scsi@6:0.0.0,1 logical name: /dev/sdc1 logical name: /media/JOUM8G version: FAT32 serial: e676-9311 size: 7394MiB capacity: 7394MiB capabilities: primary bootable fat initialized configuration: FATs=2 filesystem=fat label=Android mount.fstype=vfat mount.options=rw,nosuid,nodev,relatime,uid=999,gid=999,fmask=0022,dmask=0077,codepage=cp437,iocharset=iso8859-1,shortname=mixed,showexec,utf8,flush,errors=remount-ro state=mounted ubuntu@ubuntu:~$ ubuntu@ubuntu:~$ xinput list ? Virtual core pointer id=2 [master pointer (3)] ? ? Virtual core XTEST pointer id=4 [slave pointer (2)] ? ? Plus More Enterprise LTD. USB-compliant keyboard id=10 [slave pointer (2)] ? ? USB Optical Mouse id=11 [slave pointer (2)] ? Virtual core keyboard id=3 [master keyboard (2)] ? Virtual core XTEST keyboard id=5 [slave keyboard (3)] ? Power Button id=6 [slave keyboard (3)] ? Power Button id=7 [slave keyboard (3)] ? Sleep Button id=8 [slave keyboard (3)] ? Plus More Enterprise LTD. USB-compliant keyboard id=9 [slave keyboard (3)] ? USB 2.0 Webcam - Front id=12 [slave keyboard (3)] ? AT Translated Set 2 keyboard id=13 [slave keyboard (3)] ubuntu@ubuntu:~$

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  • CodePlex Daily Summary for Wednesday, June 16, 2010

    CodePlex Daily Summary for Wednesday, June 16, 2010New ProjectsAtomFeedBuilder: Simple and lightweight Atom feed builder. Developed in VB.Net.Cable and Wire harness tester: If you build lots of cable/wire harness' you know that testing them is a pain. I have wanted an automated cable tester for a while now but commerci...Carmenta Engine Power Pack: The target of Carmenta Engine Power Pack is to provide extensions, utilities and wrapper classes that allows developers to work more efficiently w...Customer Book: Customer Book, its like address book with facility for generating quotation for a business or a supplier to the clients.Dialector: Using this program, you can convert pure Turkish texts into different dialects; such as: Emmi, Kufurbaz, Kusdili, Laz, Peltek, Tiki, and many more....Downline Commision Generator: Analyze the compensations plan of the organizations in multi-level marketing or network marketing. Check with this tool the commision plan of the c...EmbeddedSpark 2010 Project M: Project M is a system for seamlessly interfacing a tabletop interface to portable devices placed upon it. Using image recognition and projectors, P...Event Log Creator by eVestment Alliance: Provides a simple utility to create a new source and log in the Windows event log. The utility checks if the current user is an administrator, and...ExchangeHog: Desktop/daemon application that aggregates emails from multiple pop3-accounts into single Microsoft Exchange 2010 account. For users receiving ema...Extra Time Calculator: Extra Time Calculator allows exam end times to be easily calculated for students receiving an extra time accommodation.Generic WCF Hosting Service: The Generic Host Service provides a simple, reusable, and reliable mechanism for hosting WCF services. Google Storage for .NET: Google Storage for .NET (GSN) is an open source library that provides .NET developers with easy access to the Google Storage API. The library allo...Helium: The Helium XNA game engine is a light portable game engine designed to work on many platforms and soon to be expanded on more. Currently the helium...IconizedButton Control Set: ASP.NET WebForms IconizedButton Custom Control Set. Replaces the dull Button/LinkButton/HyperLink controls with styling and left and right aligned...Jedi Council PM List: Allows for users to process Private Message Lists on the Jedi Council forums for TheForce.Net.JetPumpDesign: 本软件为蒸气喷射泵设计计算软件 作者:申阳 单位:西安交通大学过程装备与控制工程61班log4Nez: An high personalized implementation of a logging libraryMutantFramework: Provides a common set of building blocks for building enterprise applicationsNUnit Add-in for Growl Notifications: NUnit add-in which allows to send notifications to Growl when test run is started or finished, when a first test failure occurs and so on.Object Reports: Object Reports is a "proof of concept" application which provides users the ability to visualy build queries based on data stored in the relational...openTrionyx: openTrionyx is a set of tools to make easier web application development. Includes Data, Web and plain text documents tools. Developed in C#, compl...Partial Rendering control for MVC 2: This project shows a web custom control that allow to have partial rendering using async post-back (through JQuery) in a MVC 2 web application.PowerGUI Visual Studio Extension: The PowerGUI Visual Studio Extension exposes PowerGUI as an editor in Visual Studio. PowerShell developers can now write scripts directly in Visual...PowerShell Script Provider: Write your own PowerShell provider using only script, no C# required. Module definition is provided by a Windows PowerShell 2.0 Module, which may b...Scholar: Scholar is a solution/framework for .Net developers to help with the creation of distributed data processing (think SETI@home style apps). It is in...scrabb: Scrabb help people play scrabble over net.SharePointNuke: A DotNetNuke module that connects to a SharePoint server using web services API and displays the content of a specified list. SolidWorksBackConverter: a Project to Convert a solidwork file to an older version Soma - Sql Oriented MApping framework: Sql Oriented MApping framework.SPCreate: SPCreate auto store procedure creator. It's developed in c#. SpCreate as output ADO.NET Class (C# or VB.Net) and SQL Server or MS Access Store pro...std::streambuf wrapper for COM IStream: This provides a subclass of std::streambuf that wraps a COM IStream, so you can use an IStream with any C++ code that uses iostreams or the STL alg...VACID solutions: Solutions of verification problems posed in paper "Verification of Ample Correctness of Invariants of Data-structures". Developed with various tool...Viewer: Our Goal is to create a C# project that will centeralize Image and Movie Viewing in a forms application, It will also have a Specialized Webbrowser...vsXPathTester: vsXPathTester is a utility for Developer. This help them load XML file and the run their XPath Query. The Resultant is shown in window. It save the...New Releases.Net Max Framework: Version 1.0.0: Version 1.0.0 - EstableAndrew's XNA Helpers: V1.2: Features upgraded features based off of the V1.1 code for both X86 and XBOX Additions/Changes Reworked the Texture2D and Rectangle extender namesp...BaseCalendar: BaseControls 1.2: BaseControls 1.2 contains the BaseCalendar ASP.NET control. Changes: 1.2 Exposed EffectiveVisibleDate and FirstVisibleDay methods 1.1 Rendering ...Customer Book: Customer Book Code: Bronze Release PostgreSQL database dump for Customer Book. Open PgAdmin III and restore the database dump into your server. Notice User Name for t...Data Connection Suite: Data Connections Suite v1.0.0.0: This is the first release of this incomplete component, but good enought to use in a production environment (it's what we do).DigitArchive: Build 8: Now the software works on .NET 3.5 and above. So if you have Windows 7 it installs without any pre-requisites. Changes: -Works on .NET 3.5 -Now t...Doom 64 Ex (SVN Builds): Doom 64 Ex r-738: Finally a new build after so many months. There are way to many updates to even begin to write about here just download and frag away. There is a s...DotNetNuke® Media: 03.03.00a: This release is Beta!! There is no guaranteed upgrade path to the 03.03.00 release version! Please use this to help us and test what we have. Repor...Downline Commision Generator: Downline Commision Generator: Downline Commision GeneratorElmah2 : An extensable error logger for ASP.net: 1.0 Beta 1: This is a beta release be sure to report any errors etc. Be sure to check out the documentation tab on information on how to install and configure...EPiServer Template Foundation: First compiled release: First compiled release for experimenting only! :) An introductory post will be published shortly on the blog.Helium: Initial Release: This is the initial release of the Helium Engine. Please check out the documentation link for information on how to use the engine. To see a ful...IconizedButton Control Set: IconizedButton Control Set: Taking a line from Google's play book - marking everything as Beta. Seriously, I'd like to hear some feedback before moving the Development Status...JetPumpDesign: JetPumpDesign 1.0: 当前的软件可以设计5级以内的蒸汽喷射泵。Microsoft Silverlight Analytics Framework: Version 1.4.4 Installer: Tools TargetingVisual Studio 2010 Expression Blend 4 (part of Expression Studio 4) Analytics Services Included Vendor Behavior Silverlight 3...NHibernate Sidekick Library: 0.7.0: Added a few methods for use with the NHibernate 2nd level cache (EvictAllObjectsFromCache and EvictPersistentClass). I also added the boolean optio...NHibernate Sidekick Library: 0.7.5: Fix for http://nhprof.com/Learn/Alerts/DoNotUseImplicitTransactionsNito.KitchenSink: Version 9: Dependencies Nito.Linq 0.6 Beta (released 2010-06-14) Rx 1.0.2563.0 (released 2010-06-09) Supported Platforms .NET 4.0 Client Profile, with Rx. ...NQueue: Version 1.0.0.0: Version 1.0.0.0NUnit Add-in for Growl Notifications: NUnit Add-in for Growl Notifications 1.0 build 0: The very first stable releasePartial Rendering control for MVC 2: Partial Rendering control for MVC 2: Here there is the source code and a MVC 2 web site as testPowerShell Script Provider: PSProvider 0.1: Requires PowerShell 2.0 RTM The functions in the attached ps1 script are the bare minimum for a working container-style provider (no subfolders.) ...Quick Performance Monitor: Version 1.4.3: Fixed issue where if an instance name contains backslash characters (\) the program would not load the performance counter properly. Also added sta...SharePointNuke: SharePointNuke 2.00.08: SharePointNuke 2.00.08 - Binary DotNetNuke 5.x module.Skype Voice Changer: 1.0 Updated Sample Code: This updated release is the accompanying code for the Skype Voice Changer article on Coding4Fun. Changes in this release: Added support for PreEmp...std::streambuf wrapper for COM IStream: Beta release (tested in a commercial project): This code has been tested in a custom Windows Search filter and property handler I wrote for a proprietary binary format. There may be some bugs, b...Sunlit World Scheme: Sunlit World Scheme - 20100615 - source and binary: This is the result of building the current source code in Debug mode. The source code is included. The binaries are in the SchemeCode folder along...Timo-Design / 40FINGERS DotNetNuke® Skinning Extensions: Style Helper Skin Object Beta: The 40FINGERS Style Helper Skin object allows you to add CSS and Javascript links and meta tags to the head of your page. It can also remove CSS l...Umbraco CMS: Umbraco 4.1 RC: This is the final test version of Umbraco 4.1 before the final release. PLEASE BE AWARE THAT UMBRACO 4.1 RC IS A .NET 4.0 RELEASE AND WON'T WORK O...VCC: Latest build, v2.1.30615.0: Automatic drop of latest buildWCF 4 Templates for Visual Studio 2010: UserNameForCertificate Template: Produces a WCF service application supporting username and password authentication, relying on message security to protect messages en route. Suppl...WCF 4 Templates for Visual Studio 2010: UserNameOverHttps Template: Produces a WCF service application supporting username and password authentication over HTTPS/SSL, relying on transport security to protect message...xUnit.net Contrib: xunitcontrib 0.4.1 alpha (ReSharper 5.1.1709 only): xunitcontrib release 0.4.1 (ReSharper runner) This release targets the current nightly build of ReSharper 5.1's Early Access Programme (build 1709)...Most Popular ProjectsCommunity Forums NNTP bridgeRIA Services EssentialsNeatUploadBxf (Basic XAML Framework).NET Transactional File ManagerSOLID by exampleSSIS Expression Editor & TesterWEI ShareChirpy - VS Add In For Handling Js, Css, and DotLess FilesASP.NET MVC Time PlannerMost Active ProjectsdotSpatialRhyduino - Arduino and Managed CodeCassandraemonpatterns & practices – Enterprise LibraryCommunity Forums NNTP bridgeLightweight Fluent Workflowpatterns & practices: Enterprise Library ContribNB_Store - Free DotNetNuke Ecommerce Catalog ModuleBlogEngine.NETjQuery Library for SharePoint Web Services

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  • UIButton addTarget:action:forControlEvents: results in [NSObject doesNotRecognizeSelector:]

    - by Teodor
    Hi. I tried a lot of stuff, still no result. So I have the following button created programatically in a subclass of UIViewController: rightButton = [UIButton buttonWithType:UIButtonTypeCustom]; rightButton.frame = CGRectMake(0.0, 0.0, 110.0, 40.0); rightButton.titleLabel.font = [UIFont fontWithName:GAME_FONT_NAME_STRING size:20.0]; [rightButton setTitle:@"MyTitle" forState:UIControlStateNormal]; rightButton.backgroundColor = [UIColor clearColor]; [rightButton setTitleColor:[UIColor greenColor] forState:UIControlStateNormal]; [rightButton setTitleColor:[UIColor blackColor] forState:UIControlStateHighlighted]; [rightButton setBackgroundImage:normalImage forState:UIControlStateNormal]; [rightButton setBackgroundImage:highlightedImage forState:UIControlStateHighlighted]; [rightButton addTarget:self action:@selector(myButton) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:rightButton]; where the selector is: - (void)myButton; I tried everything: - (void)myButton; - (void)myButton:(id)sender; - (void)myButton:(id)sender forEvent:(UIEvent *)event; - (IBAction)myButton; - (IBAction)myButton:(id)sender; - (IBAction)myButton:(id)sender forEvent:(UIEvent *)event; and the corresponding selectors, of course: [rightButton addTarget:self action:@selector(myButton) forControlEvents:UIControlEventTouchUpInside]; [rightButton addTarget:self action:@selector(myButton:) forControlEvents:UIControlEventTouchUpInside]; [rightButton addTarget:self action:@selector(myButton:forEvent:) forControlEvents:UIControlEventTouchUpInside]; [rightButton addTarget:self action:@selector(myButton) forControlEvents:UIControlEventTouchUpInside]; [rightButton addTarget:self action:@selector(myButton:) forControlEvents:UIControlEventTouchUpInside]; [rightButton addTarget:self action:@selector(myButton:forEvent:) forControlEvents:UIControlEventTouchUpInside]; The result is always an uncaught exception - [NSObject doesNotRecognizeSelector:]. However, the usual backtrace of the program is: #0 0x92a6bedb in objc_msgSend () #1 0x03b0a430 in ?? () #2 0x00306b4e in -[UIControl sendAction:to:forEvent:] () #3 0x00308d6f in -[UIControl(Internal) _sendActionsForEvents:withEvent:] () #4 0x00307abb in -[UIControl touchesEnded:withEvent:] () #5 0x002bcddf in -[UIWindow _sendTouchesForEvent:] () #6 0x002a67c8 in -[UIApplication sendEvent:] () #7 0x002ad061 in _UIApplicationHandleEvent () #8 0x02498d59 in PurpleEventCallback () #9 0x01cabb80 in CFRunLoopRunSpecific () #10 0x01caac48 in CFRunLoopRunInMode () #11 0x02497615 in GSEventRunModal () #12 0x024976da in GSEventRun () #13 0x002adfaf in UIApplicationMain () So what is the problem with that button? PS: I am using the iPhone SDK 3.1.3 Update! The following code in the AppDelegate (no declarations in the interface): - (void)applicationDidFinishLaunching:(UIApplication *)application { UIButton *test = [[UIButton alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 100.0)]; [test setTitle:@"Title" forState:UIControlStateNormal]; UIImage *bg = [UIImage imageNamed:...]; [test setBackgroundImage:bg forState:UIControlStateNormal]; [test addTarget:self action:@selector(testAction) forControlEvents:UIControlEventTouchUpInside]; [window addSubview:test]; [test release]; [window makeKeyAndVisible]; } - (void)testAction { NSLog(@"Write something..."); } works perfectly! But if I create an empty UIViewController with the same code: - (void)viewDidLoad { UIButton *test = [[UIButton alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 100.0)]; [test setTitle:@"Title" forState:UIControlStateNormal]; UIImage *bg = [UIImage imageNamed:...]; [test setBackgroundImage:bg forState:UIControlStateNormal]; [test addTarget:self action:@selector(testAction) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:test]; [test release]; [window makeKeyAndVisible]; } - (void)testAction { NSLog(@"Write something..."); } I get this mysterious error. :-( Help!

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  • HPET for x86 BSP (how to build it for WCE8)

    - by Werner Willemsens
    Originally posted on: http://geekswithblogs.net/WernerWillemsens/archive/2014/08/02/157895.aspx"I needed a timer". That is how we started a few blogs ago our series about APIC and ACPI. Well, here it is. HPET (High Precision Event Timer) was introduced by Intel in early 2000 to: Replace old style Intel 8253 (1981!) and 8254 timers Support more accurate timers that could be used for multimedia purposes. Hence Microsoft and Intel sometimes refers to HPET as Multimedia timers. An HPET chip consists of a 64-bit up-counter (main counter) counting at a frequency of at least 10 MHz, and a set of (at least three, up to 256) comparators. These comparators are 32- or 64-bit wide. The HPET is discoverable via ACPI. The HPET circuit in recent Intel platforms is integrated into the SouthBridge chip (e.g. 82801) All HPET timers should support one-shot interrupt programming, while optionally they can support periodic interrupts. In most Intel SouthBridges I worked with, there are three HPET timers. TIMER0 supports both one-shot and periodic mode, while TIMER1 and TIMER2 are one-shot only. Each HPET timer can generate interrupts, both in old-style PIC mode and in APIC mode. However in PIC mode, interrupts cannot freely be chosen. Typically IRQ11 is available and cannot be shared with any other interrupt! Which makes the HPET in PIC mode virtually unusable. In APIC mode however more IRQs are available and can be shared with other interrupt generating devices. (Check the datasheet of your SouthBridge) Because of this higher level of freedom, I created the APIC BSP (see previous posts). The HPET driver code that I present you here uses this APIC mode. Hpet.reg [HKEY_LOCAL_MACHINE\Drivers\BuiltIn\Hpet] "Dll"="Hpet.dll" "Prefix"="HPT" "Order"=dword:10 "IsrDll"="giisr.dll" "IsrHandler"="ISRHandler" "Priority256"=dword:50 Because HPET does not reside on the PCI bus, but can be found through ACPI as a memory mapped device, you don't need to specify the "Class", "SubClass", "ProgIF" and other PCI related registry keys that you typically find for PCI devices. If a driver needs to run its internal thread(s) at a certain priority level, by convention in Windows CE you add the "Priority256" registry key. Through this key you can easily play with the driver's thread priority for better response and timer accuracy. See later. Hpet.cpp (Hpet.dll) This cpp file contains the complete HPET driver code. The file is part of a folder that you typically integrate in your BSP (\src\drivers\Hpet). It is written as sample (example) code, you most likely want to change this code to your specific needs. There are two sets of #define's that I use to control how the driver works. _TRIGGER_EVENT or _TRIGGER_SEMAPHORE: _TRIGGER_EVENT will let your driver trigger a Windows CE Event when the timer expires, _TRIGGER_SEMAPHORE will trigger a Windows CE counting Semaphore. The latter guarantees that no events get lost in case your application cannot always process the triggers fast enough. _TIMER0 or _TIMER2: both timers will trigger an event or semaphore periodically. _TIMER0 will use a periodic HPET timer interrupt, while _TIMER2 will reprogram a one-shot HPET timer after each interrupt. The one-shot approach is interesting if the frequency you wish to generate is not an even multiple of the HPET main counter frequency. The sample code uses an algorithm to generate a more correct frequency over a longer period (by reducing rounding errors). _TIMER1 is not used in the sample source code. HPT_Init() will locate the HPET I/O memory space, setup the HPET counter (_TIMER0 or _TIMER2) and install the Interrupt Service Thread (IST). Upon timer expiration, the IST will run and on its turn will generate a Windows CE Event or Semaphore. In case of _TIMER2 a new one-shot comparator value is calculated and set for the timer. The IRQ of the HPET timers are programmed to IRQ22, but you can choose typically from 20-23. The TIMERn_INT_ROUT_CAP bits in the TIMn_CONF register will tell you what IRQs you can choose from. HPT_IOControl() can be used to set a new HPET counter frequency (actually you configure the counter timeout value in microseconds), start and stop the timer, and request the current HPET counter value. The latter is interesting because the Windows CE QueryPerformanceCounter() and QueryPerformanceFrequency() APIs implement the same functionality, albeit based on other counter implementations. HpetDrvIst() contains the IST code. DWORD WINAPI HpetDrvIst(LPVOID lpArg) { psHpetDeviceContext pHwContext = (psHpetDeviceContext)lpArg; DWORD mainCount = READDWORD(pHwContext->g_hpet_va, GenCapIDReg + 4); // Main Counter Tick period (fempto sec 10E-15) DWORD i = 0; while (1) { WaitForSingleObject(pHwContext->g_isrEvent, INFINITE); #if defined(_TRIGGER_SEMAPHORE) LONG p = 0; BOOL b = ReleaseSemaphore(pHwContext->g_triggerEvent, 1, &p); #elif defined(_TRIGGER_EVENT) BOOL b = SetEvent(pHwContext->g_triggerEvent); #else #pragma error("Unknown TRIGGER") #endif #if defined(_TIMER0) DWORD currentCount = READDWORD(pHwContext->g_hpet_va, MainCounterReg); DWORD comparator = READDWORD(pHwContext->g_hpet_va, Tim0_ComparatorReg + 0); SETBIT(pHwContext->g_hpet_va, GenIntStaReg, 0); // clear interrupt on HPET level InterruptDone(pHwContext->g_sysIntr); // clear interrupt on OS level _LOGMSG(ZONE_INTERRUPT, (L"%s: HpetDrvIst 0 %06d %08X %08X", pHwContext->g_id, i++, currentCount, comparator)); #elif defined(_TIMER2) DWORD currentCount = READDWORD(pHwContext->g_hpet_va, MainCounterReg); DWORD previousComparator = READDWORD(pHwContext->g_hpet_va, Tim2_ComparatorReg + 0); pHwContext->g_counter2.QuadPart += pHwContext->g_comparator.QuadPart; // increment virtual counter (higher accuracy) DWORD comparator = (DWORD)(pHwContext->g_counter2.QuadPart >> 8); // "round" to real value WRITEDWORD(pHwContext->g_hpet_va, Tim2_ComparatorReg + 0, comparator); SETBIT(pHwContext->g_hpet_va, GenIntStaReg, 2); // clear interrupt on HPET level InterruptDone(pHwContext->g_sysIntr); // clear interrupt on OS level _LOGMSG(ZONE_INTERRUPT, (L"%s: HpetDrvIst 2 %06d %08X %08X (%08X)", pHwContext->g_id, i++, currentCount, comparator, comparator - previousComparator)); #else #pragma error("Unknown TIMER") #endif } return 1; } The following figure shows how the HPET hardware interrupt via ISR -> IST is translated in a Windows CE Event or Semaphore by the HPET driver. The Event or Semaphore can be used to trigger a Windows CE application. HpetTest.cpp (HpetTest.exe)This cpp file contains sample source how to use the HPET driver from an application. The file is part of a separate (smart device) VS2013 solution. It contains code to measure the generated Event/Semaphore times by means of GetSystemTime() and QueryPerformanceCounter() and QueryPerformanceFrequency() APIs. HPET evaluation If you scan the internet about HPET, you'll find many remarks about buggy HPET implementations and bad performance. Unfortunately that is true. I tested the HPET driver on an Intel ICH7M SBC (release date 2008). When a HPET timer expires on the ICH7M, an interrupt indeed is generated, but right after you clear the interrupt, a few more unwanted interrupts (too soon!) occur as well. I tested and debugged it for a loooong time, but I couldn't get it to work. I concluded ICH7M's HPET is buggy Intel hardware. I tested the HPET driver successfully on a more recent NM10 SBC (release date 2013). With the NM10 chipset however, I am not fully convinced about the timer's frequency accuracy. In the long run - on average - all is fine, but occasionally I experienced upto 20 microseconds delays (which were immediately compensated on the next interrupt). Of course, this was all measured by software, but I still experienced the occasional delay when both the HPET driver IST thread as the application thread ran at CeSetThreadPriority(1). If it is not the hardware, only the kernel can cause this delay. But Windows CE is an RTOS and I have never experienced such long delays with previous versions of Windows CE. I tested and developed this on WCE8, I am not heavily experienced with it yet. Internet forum threads however mention inaccurate HPET timer implementations as well. At this moment I haven't figured out what is going on here. Useful references: http://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/software-developers-hpet-spec-1-0a.pdf http://en.wikipedia.org/wiki/High_Precision_Event_Timer http://wiki.osdev.org/HPET Windows CE BSP source file package for HPET in MyBsp Note that this source code is "As Is". It is still under development and I cannot (and never will) guarantee the correctness of the code. Use it as a guide for your own HPET integration.

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  • WCF: Configuring Known Types

    - by jerbersoft
    I want to know as to how to configure known types in WCF. For example, I have a Person class and an Employee class. The Employee class is a sublass of the Person class. Both class are marked with a [DataContract] attribute. I dont want to hardcode the known type of a class, like putting a [ServiceKnownType(typeof(Employee))] at the Person class so that WCF will know that Employee is a subclass of Person. Now, I added to the host's App.config the following XML configuration: <?xml version="1.0" encoding="utf-8" ?> <configuration> <system.runtime.serialization> <dataContractSerializer> <declaredTypes> <add type="Person, WCFWithNoLibrary, Version=1.0.0.0,Culture=neutral,PublicKeyToken=null"> <knownType type="Employee, WCFWithNoLibrary, Version=1.0.0.0,Culture=neutral, PublicKeyToken=null" /> </add> </declaredTypes> </dataContractSerializer> </system.runtime.serialization> <system.serviceModel> ....... </system.serviceModel> </configuration> I compiled it, run the host, added a service reference at the client and added some code and run the client. But an error occured: The formatter threw an exception while trying to deserialize the message: There was an error while trying to deserialize parameter http://www.herbertsabanal.net:person. The InnerException message was 'Error in line 1 position 247. Element 'http://www.herbertsabanal.net:person' contains data of the 'http://www.herbertsabanal.net/Data:Employee' data contract. The deserializer has no knowledge of any type that maps to this contract. Add the type corresponding to 'Employee' to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding it to the list of known types passed to DataContractSerializer.'. Please see InnerException for more details. Below are the data contracts: [DataContract(Namespace="http://www.herbertsabanal.net/Data", Name="Person")] class Person { string _name; int _age; [DataMember(Name="Name", Order=0)] public string Name { get { return _name; } set { _name = value; } } [DataMember(Name="Age", Order=1)] public int Age { get { return _age; } set { _age = value; } } } [DataContract(Namespace="http://www.herbertsabanal.net/Data", Name="Employee")] class Employee : Person { string _id; [DataMember] public string ID { get { return _id; } set { _id = value; } } } Btw, I didn't use class libraries (WCF class libraries or non-WCF class libraries) for my service. I just plain coded it in the host project. I guess there must be a problem at the config file (please see config file above). Or I must be missing something. Any help would be pretty much appreciated.

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  • Python/numpy tricky slicing problem

    - by daver
    Hi stack overflow, I have a problem with some numpy stuff. I need a numpy array to behave in an unusual manner by returning a slice as a view of the data I have sliced, not a copy. So heres an example of what I want to do: Say we have a simple array like this: a = array([1, 0, 0, 0]) I would like to update consecutive entries in the array (moving left to right) with the previous entry from the array, using syntax like this: a[1:] = a[0:3] This would get the following result: a = array([1, 1, 1, 1]) Or something like this: a[1:] = 2*a[:3] # a = [1,2,4,8] To illustrate further I want the following kind of behaviour: for i in range(len(a)): if i == 0 or i+1 == len(a): continue a[i+1] = a[i] Except I want the speed of numpy. The default behavior of numpy is to take a copy of the slice, so what I actually get is this: a = array([1, 1, 0, 0]) I already have this array as a subclass of the ndarray, so I can make further changes to it if need be, I just need the slice on the right hand side to be continually updated as it updates the slice on the left hand side. Am I dreaming or is this magic possible? Update: This is all because I am trying to use Gauss-Seidel iteration to solve a linear algebra problem, more or less. It is a special case involving harmonic functions, I was trying to avoid going into this because its really not necessary and likely to confuse things further, but here goes. The algorithm is this: while not converged: for i in range(len(u[:,0])): for j in range(len(u[0,:])): # skip over boundary entries, i,j == 0 or len(u) u[i,j] = 0.25*(u[i-1,j] + u[i+1,j] + u[i, j-1] + u[i,j+1]) Right? But you can do this two ways, Jacobi involves updating each element with its neighbours without considering updates you have already made until the while loop cycles, to do it in loops you would copy the array then update one array from the copied array. However Gauss-Seidel uses information you have already updated for each of the i-1 and j-1 entries, thus no need for a copy, the loop should essentially 'know' since the array has been re-evaluated after each single element update. That is to say, every time we call up an entry like u[i-1,j] or u[i,j-1] the information calculated in the previous loop will be there. I want to replace this slow and ugly nested loop situation with one nice clean line of code using numpy slicing: u[1:-1,1:-1] = 0.25(u[:-2,1:-1] + u[2:,1:-1] + u[1:-1,:-2] + u[1:-1,2:]) But the result is Jacobi iteration because when you take a slice: u[:,-2,1:-1] you copy the data, thus the slice is not aware of any updates made. Now numpy still loops right? Its not parallel its just a faster way to loop that looks like a parallel operation in python. I want to exploit this behaviour by sort of hacking numpy to return a pointer instead of a copy when I take a slice. Right? Then every time numpy loops, that slice will 'update' or really just replicate whatever happened in the update. To do this I need slices on both sides of the array to be pointers. Anyway if there is some really really clever person out there that awesome, but I've pretty much resigned myself to believing the only answer is to loop in C.

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  • The Java Specialist: An Interview with Java Champion Heinz Kabutz

    - by Janice J. Heiss
    Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean. Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science. He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them. Q: Tell us about your JavaOne plans.A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies. Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.) Q: What sessions are you attending that we should know about?A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.Q: Give us an update on the Java Specialists’ Newsletter.A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.Here is a little memory puzzle for your readers: public class JavaMemoryPuzzle {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();    jmp.f();  }}When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError: public class JavaMemoryPuzzlePolite {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    for(int i=0; i<10; i++) {      System.out.println("Please be so kind and release memory");    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();    jmp.f();    System.out.println("No OutOfMemoryError");  }}Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself. Q: What do you think Java developers should know that they currently do not know?A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?” Q: What are you looking forward to in Java 8?A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers. Originally published on blogs.oracle.com/javaone.

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  • The Java Specialist: An Interview with Java Champion Heinz Kabutz

    - by Janice J. Heiss
    Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean. Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science. He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them. Q: Tell us about your JavaOne plans.A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies. Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.) Q: What sessions are you attending that we should know about?A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.Q: Give us an update on the Java Specialists’ Newsletter.A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.Here is a little memory puzzle for your readers: public class JavaMemoryPuzzle {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();    jmp.f();  }}When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError: public class JavaMemoryPuzzlePolite {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    for(int i=0; i<10; i++) {      System.out.println("Please be so kind and release memory");    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();    jmp.f();    System.out.println("No OutOfMemoryError");  }}Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself. Q: What do you think Java developers should know that they currently do not know?A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?” Q: What are you looking forward to in Java 8?A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers.

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  • C#: Inheritence, Overriding, and Hiding

    - by Rosarch
    I'm having difficulty with an architectural decision for my C# XNA game. The basic entity in the world, such as a tree, zombie, or the player, is represented as a GameObject. Each GameObject is composed of at least a GameObjectController, GameObjectModel, and GameObjectView. These three are enough for simple entities, like inanimate trees or rocks. However, as I try to keep the functionality as factored out as possible, the inheritance begins to feel unwieldy. Syntactically, I'm not even sure how best to accomplish my goals. Here is the GameObjectController: public class GameObjectController { protected GameObjectModel model; protected GameObjectView view; public GameObjectController(GameObjectManager gameObjectManager) { this.gameObjectManager = gameObjectManager; model = new GameObjectModel(this); view = new GameObjectView(this); } public GameObjectManager GameObjectManager { get { return gameObjectManager; } } public virtual GameObjectView View { get { return view; } } public virtual GameObjectModel Model { get { return model; } } public virtual void Update(long tick) { } } I want to specify that each subclass of GameObjectController will have accessible at least a GameObjectView and GameObjectModel. If subclasses are fine using those classes, but perhaps are overriding for a more sophisticated Update() method, I don't want them to have to duplicate the code to produce those dependencies. So, the GameObjectController constructor sets those objects up. However, some objects do want to override the model and view. This is where the trouble comes in. Some objects need to fight, so they are CombatantGameObjects: public class CombatantGameObject : GameObjectController { protected new readonly CombatantGameModel model; public new virtual CombatantGameModel Model { get { return model; } } protected readonly CombatEngine combatEngine; public CombatantGameObject(GameObjectManager gameObjectManager, CombatEngine combatEngine) : base(gameObjectManager) { model = new CombatantGameModel(this); this.combatEngine = combatEngine; } public override void Update(long tick) { if (model.Health <= 0) { gameObjectManager.RemoveFromWorld(this); } base.Update(tick); } } Still pretty simple. Is my use of new to hide instance variables correct? Note that I'm assigning CombatantObjectController.model here, even though GameObjectController.Model was already set. And, combatants don't need any special view functionality, so they leave GameObjectController.View alone. Then I get down to the PlayerController, at which a bug is found. public class PlayerController : CombatantGameObject { private readonly IInputReader inputReader; private new readonly PlayerModel model; public new PlayerModel Model { get { return model; } } private float lastInventoryIndexAt; private float lastThrowAt; public PlayerController(GameObjectManager gameObjectManager, IInputReader inputReader, CombatEngine combatEngine) : base(gameObjectManager, combatEngine) { this.inputReader = inputReader; model = new PlayerModel(this); Model.Health = Constants.PLAYER_HEALTH; } public override void Update(long tick) { if (Model.Health <= 0) { gameObjectManager.RemoveFromWorld(this); for (int i = 0; i < 10; i++) { Debug.WriteLine("YOU DEAD SON!!!"); } return; } UpdateFromInput(tick); // .... } } The first time that this line is executed, I get a null reference exception: model.Body.ApplyImpulse(movementImpulse, model.Position); model.Position looks at model.Body, which is null. This is a function that initializes GameObjects before they are deployed into the world: public void Initialize(GameObjectController controller, IDictionary<string, string> data, WorldState worldState) { controller.View.read(data); controller.View.createSpriteAnimations(data, _assets); controller.Model.read(data); SetUpPhysics(controller, worldState, controller.Model.BoundingCircleRadius, Single.Parse(data["x"]), Single.Parse(data["y"]), bool.Parse(data["isBullet"])); } Every object is passed as a GameObjectController. Does that mean that if the object is really a PlayerController, controller.Model will refer to the base's GameObjectModel and not the PlayerController's overriden PlayerObjectModel?

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  • Dynamic model choice field in django formset using multiple select elements

    - by Aryeh Leib Taurog
    I posted this question on the django-users list, but haven't had a reply there yet. I have models that look something like this: class ProductGroup(models.Model): name = models.CharField(max_length=10, primary_key=True) def __unicode__(self): return self.name class ProductRun(models.Model): date = models.DateField(primary_key=True) def __unicode__(self): return self.date.isoformat() class CatalogItem(models.Model): cid = models.CharField(max_length=25, primary_key=True) group = models.ForeignKey(ProductGroup) run = models.ForeignKey(ProductRun) pnumber = models.IntegerField() def __unicode__(self): return self.cid class Meta: unique_together = ('group', 'run', 'pnumber') class Transaction(models.Model): timestamp = models.DateTimeField() user = models.ForeignKey(User) item = models.ForeignKey(CatalogItem) quantity = models.IntegerField() price = models.FloatField() Let's say there are about 10 ProductGroups and 10-20 relevant ProductRuns at any given time. Each group has 20-200 distinct product numbers (pnumber), so there are at least a few thousand CatalogItems. I am working on formsets for the Transaction model. Instead of a single select menu with the several thousand CatalogItems for the ForeignKey field, I want to substitute three drop-down menus, for group, run, and pnumber, which uniquely identify the CatalogItem. I'd also like to limit the choices in the second two drop-downs to those runs and pnumbers which are available for the currently selected product group (I can update them via AJAX if the user changes the product group, but it's important that the initial page load as described without relying on AJAX). What's the best way to do this? As a point of departure, here's what I've tried/considered so far: My first approach was to exclude the item foreign key field from the form, add the substitute dropdowns by overriding the add_fields method of the formset, and then extract the data and populate the fields manually on the model instances before saving them. It's straightforward and pretty simple, but it's not very reusable and I don't think it is the right way to do this. My second approach was to create a new field which inherits both MultiValueField and ModelChoiceField, and a corresponding MultiWidget subclass. This seems like the right approach. As Malcolm Tredinnick put it in a django-users discussion, "the 'smarts' of a field lie in the Field class." The problem I'm having is when/where to fetch the lists of choices from the db. The code I have now does it in the Field's __init__, but that means I have to know which ProductGroup I'm dealing with before I can even define the Form class, since I have to instantiate the Field when I define the form. So I have a factory function which I call at the last minute from my view--after I know what CatalogItems I have and which product group they're in--to create form/formset classes and instantiate them. It works, but I wonder if there's a better way. After all, the field should be able to determine the correct choices much later on, once it knows its current value. Another problem is that my implementation limits the entire formset to transactions relating to (CatalogItems from) a single ProductGroup. A third possibility I'm entertaining is to put it all in the Widget class. Once I have the related model instance, or the cid, or whatever the widget is given, I can get the ProductGroup and construct the drop-downs. This would solve the issues with my second approach, but doesn't seem like the right approach.

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  • Problem exporting NSOpenGLView pixel data to some image file formats using ImageKit & CGImageDestina

    - by walkytalky
    I am developing an application to visualise some experimental data. One of its functions is to render the data in an NSOpenGLView subclass, and allow the resulting image to be exported to a file or copied to the clipboard. The view exports the data as an NSImage, generated like this: - (NSImage*) image { NSBitmapImageRep* imageRep; NSImage* image; NSSize viewSize = [self bounds].size; int width = viewSize.width; int height = viewSize.height; [self lockFocus]; [self drawRect:[self bounds]]; [self unlockFocus]; imageRep=[[[NSBitmapImageRep alloc] initWithBitmapDataPlanes:NULL pixelsWide:width pixelsHigh:height bitsPerSample:8 samplesPerPixel:4 hasAlpha:YES isPlanar:NO colorSpaceName:NSDeviceRGBColorSpace bytesPerRow:width*4 bitsPerPixel:32] autorelease]; [[self openGLContext] makeCurrentContext]; glReadPixels(0,0,width,height,GL_RGBA,GL_UNSIGNED_BYTE,[imageRep bitmapData]); image=[[[NSImage alloc] initWithSize:NSMakeSize(width,height)] autorelease]; [image addRepresentation:imageRep]; [image setFlipped:YES]; // this is deprecated in 10.6 [image lockFocusOnRepresentation:imageRep]; // this will flip the rep [image unlockFocus]; return image; } Copying uses this image very simply, like this: - (IBAction) copy:(id) sender { NSImage* img = [self image]; NSPasteboard* pb = [NSPasteboard generalPasteboard]; [pb clearContents]; NSArray* copied = [NSArray arrayWithObject:img]; [pb writeObjects:copied]; } For file writing, I use the ImageKit IKSaveOptions accessory panel to set the output file type and associated options, then use the following code to do the writing: NSImage* glImage = [glView image]; NSRect rect = [glView bounds]; rect.origin.x = rect.origin.y = 0; img = [glImage CGImageForProposedRect:&rect context:[NSGraphicsContext currentContext] hints:nil]; if (img) { NSURL* url = [NSURL fileURLWithPath: path]; CGImageDestinationRef dest = CGImageDestinationCreateWithURL((CFURLRef)url, (CFStringRef)newUTType, 1, NULL); if (dest) { CGImageDestinationAddImage(dest, img, (CFDictionaryRef)[imgSaveOptions imageProperties]); CGImageDestinationFinalize(dest); CFRelease(dest); } } (I've trimmed a bit of extraneous code here, but nothing that would affect the outcome as far as I can see. The newUTType comes from the IKSaveOptions panel.) This works fine when the file is exported as GIF, JPEG, PNG, PSD or TIFF, but exporting to PDF, BMP, TGA, ICNS and JPEG-2000 produces a red colour artefact on part of the image. Example images are below, the first exported as JPG, the second as PDF. Copy to clipboard does not exhibit this red stripe with the current implementation of image, but it did with the original implementation, which generated the imageRep using NSCalibratedRGBColorSpace rather than NSDeviceRGBColorSpace. So I'm guessing there's some issue with the colour representation in the pixels I get from OpenGL that doesn't get through the subsequent conversions properly, but I'm at a loss as to what to do about it. So, can anyone tell me (i) what is causing this, and (ii) how can I make it go away? I don't care so much about all of the formats but I'd really like at least PDF to work.

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  • How can I bind events to strongly typed datasets of different types?

    My application contains several forms which consist of a strongly typed datagridview, a strongly typed bindingsource, and a strongly typed table adapter. I am using some code in each form to update the database whenever the user leaves the current row, shifts focus away from the datagrid or the form, or closes the form. This code is the same in each case, so I want to make a subclass of form, from which all of these forms can inherit. But the strongly typed data objects all inherit from component, which doesn't expose the events I want to bind to or the methods I want to invoke. The only way I can see of gaining access to the events is to use: Type(string Name).GetEvent(string EventName).AddEventHandler(object Target,Delegate Handler) Similarly, I want to call the Update method of the strongly typed table adapter, and am using Type(string Name).GetMethod(String name, Type[] params).Invoke(object target, object[] params). It works ok, but it seems very heavy handed. Is there a better way? Here is my code for the main class: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; using System.ComponentModel; namespace MyApplication { public class AutoSaveDataGridForm: Form { private DataRow PreviousRow; public Component Adapter { private get; set; } private Component dataGridView; public Component DataGridView { private get { return dataGridView; } set { dataGridView = value; Type t = dataGridView.GetType(); t.GetEvent("Leave").AddEventHandler(dataGridView, new EventHandler(DataGridView_Leave)); } } private Component bindingSource; public Component BindingSource { private get { return bindingSource; } set { bindingSource = value; Type t = bindingSource.GetType(); t.GetEvent("PositionChanged").AddEventHandler(bindingSource, new EventHandler(BindingSource_PositionChanged)); } } protected void Save() { if (PreviousRow != null && PreviousRow.RowState != DataRowState.Unchanged) { Type t = Adapter.GetType(); t.GetMethod("Update", new Type[] { typeof(DataRow[]) }).Invoke(Adapter, new object[] { new DataRow[] { PreviousRow } }); } } private void BindingSource_PositionChanged(object sender, EventArgs e) { BindingSource bindingSource = sender as BindingSource; DataRowView CurrentRowView = bindingSource.Current as DataRowView; DataRow CurrentRow = CurrentRowView.Row; if (PreviousRow != null && PreviousRow != CurrentRow) { Save(); } PreviousRow = CurrentRow; } private void InitializeComponent() { this.SuspendLayout(); // // AutoSaveDataGridForm // this.FormClosed += new System.Windows.Forms.FormClosedEventHandler(this.AutoSaveDataGridForm_FormClosed); this.Leave += new System.EventHandler(this.AutoSaveDataGridForm_Leave); this.ResumeLayout(false); } private void DataGridView_Leave(object sender, EventArgs e) { Save(); } private void AutoSaveDataGridForm_FormClosed(object sender, FormClosedEventArgs e) { Save(); } private void AutoSaveDataGridForm_Leave(object sender, EventArgs e) { Save(); } } } And here is a (partial) form which implements it: public partial class FileTypesInherited :AutoSaveDataGridForm { public FileTypesInherited() { InitializeComponent(); } private void FileTypesInherited_Load(object sender, EventArgs e) { // TODO: This line of code loads data into the 'sharedFoldersInformationV2DataSet.tblFileTypes' table. You can move, or remove it, as needed. this.tblFileTypesTableAdapter.Fill(this.sharedFoldersInformationV2DataSet.tblFileTypes); this.BindingSource = tblFileTypesBindingSource; this.Adapter = tblFileTypesTableAdapter; this.DataGridView = tblFileTypesDataGridView; } }

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  • Populating a GridView with ImageViews dynamically/programmatically using a ImageAdapter

    - by Julian Vogels
    Hi folks, this is my first question at stackoverflow, but it's a little tricky already... I try to develop an Android App which allows the user to fetch data from flickr and show it in a gridview (with some nice 3D-Animation). After some adventures i got it almost running, but now I'm stuck. Here's the problem: I got a UI Thread "LoadPhotosTask" which gets the pictures from flickr, just like the open source application photostream. In the method onProgressUpdate(LoadedPhoto... value) of that subclass I call addPhoto(). Until now everythings fine - I got some nice Bitmap and Flickr.photo data with all the information I need. @Override public void onProgressUpdate(LoadedPhoto... value) { addPhoto(value); } On the other hand I have got a GridView. Now I want to fill it with the Photos. It has got an adapter called ImageAdapter (which extends BaseAdapter, see this tutorial). If I use an array inside the ImageAdapter class I can populate the GridView with some sample images. But if I want to populate it at runtime, I don't know what to do. How do I have to set up the getView method in the ImageAdapter? I was trying to fill the array inside the ImageAdapter class with my values in addPhoto, but it doesn't display anything. So first of all I was setting up the array with the amount of Photos i wanted to display in the grid like that (code is inside the ImageAdapter class): // class variable private ImageView[] mThumbIds; [...] public void setupArray(int count) { this.mThumbIds = new ImageView[count]; } Then I call this method with the lenght of my photolist: final Flickr.PhotoList list = params[0]; final int count = list.getCount(); int helper = 0; imagead.setupArray(count); Afterwards I call the getView method manually inside the addPhoto method: private void addPhoto(LoadedPhoto... value) { ImageView image = (ImageView) mInflater.inflate( R.layout.grid_item_photo, null); image.setImageBitmap(value[0].mBitmap); image.setTag(value[0].mPhoto); imagead.setmThumbIds(image, value[0].mPosition); imagead.getView(value[0].mPosition, null, mpicturesGrid); } That is the getView method inside ImageAdapter: public View getView(int position, View convertView, ViewGroup parent) { if (convertView == null) { // if it's not recycled, initialize some // attributes imageView = new ImageView(mContext); imageView.setLayoutParams(new GridView.LayoutParams(EDGE_LENGTH, EDGE_LENGTH)); imageView.setScaleType(ImageView.ScaleType.CENTER_CROP); imageView.setPadding(0, 0, 0, 0); imageView.setVisibility(View.VISIBLE); } else { imageView = (ImageView) convertView; } imageView.setImageDrawable(mThumbIds[position].getDrawable()); imageView.setTag(mThumbIds[position].getTag()); return imageView; } Ok, finally I apologize for my poor english and I hope you can give me some help with the information I provided. Greetings, Julian

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