Hi, This should hopefully be a simple one. I would like to add an extension method to the System.Web.Mvc.ViewPage< T > class. How should this extension method look? My first intuitive thought is something like this: namespace System.Web.Mvc { public static class ViewPageExtensions { public static string GetDefaultPag...
Since generics were introduced, Class is parametrized, so that List.class produces Class<List>. This is clear. What I am not able to figure out is how to get a instance of Class of type which is parametrized itself, i.e. Class<List<String>>. Like in this snippet: public class GenTest { static <T> T instantiate(Class<T> clazz) throw...
Is it possible to create an instance of a generic type in Java? I'm thinking based on what I've seen that the answer is "no" (due to type erasure), but I'd be interested if anyone can see something I'm missing: class SomeContainer<E> { E createContents() { return what??? } } EDIT: It turns out that Super Type Token...
I thought I'd offer this softball to whomever would like to hit it out of the park. What are generics, what are the advantages of generics, why, where, how should I use them? Please, keep it fairly basic. Thanks. ...
I'm building a function to extend the Enum.Parse concept that Allows a default value to be parsed in case that an Enum value is not found Is case insensitive So I wrote the following: public static T GetEnumFromString<T>(string value, T defaultValue) where T : Enum { if (string.IsNullOrEmpty(value)) return defaultValue; fore...
I have the concept of NodeTypes and Nodes. A NodeType is a bunch of meta-data which you can create Node instances from (a lot like the whole Class / Object relationship). I have various NodeType implementations and various Node implementations. In my AbstractNodeType (top level for NodeTypes) I have ab abstract createInstance() method...
I've never used any of the .NET generics in my work, but I understand that they are fairly popular. Does anyone have any good links or book suggestions for learning them? As a bonus; I only vaguely understand what .NET generic collections are and what they do...does anyone have any practical examples of how they might be used to greate...
I want to be able to do this. MyInterface interface = new ServiceProxyHelper<ProxyType>(); Here's the object structure MyTypeThatImplementsMyInterface : MyInterface Will this work? public class ProxyType : MyInterface {} public class ServiceProxyHelper<ProxyType> : IDisposable, MyInterface {} ...
The system I work on here was written before .net 2.0 and didn't have the benefit of generics. It was eventually updated to 2.0, but none of the code was refactored due to time constraints. There are a number of places where the code uses ArraysLists etc. that store things as objects. From performance perspective, how important chan...
This isn't legal: public class MyBaseClass { public MyBaseClass() {} public MyBaseClass(object arg) {} } public void ThisIsANoNo<T>() where T : MyBaseClass { T foo = new T("whoops!"); } In order to do this, you have to do some reflection on the type object for T or you have to use Activator.CreateInstance. Both are pretty nas...
If I am writing a library and I have a function that needs to return a sequence of values, I could do something like: std::vector<int> get_sequence(); However, this requires the library user to use the std::vector<> container rather than allowing them to use whatever container they want to use. In addition, it can add an extra copy o...
C# question (.net 3.5). I have a class, ImageData, that has a field ushort[,] pixels. I am dealing with proprietary image formats. The ImageData class takes a file location in the constructor, then switches on file extension to determine how to decode. In several of the image files, there is a "bit depth" field in the header. After ...
I am working on an application that is about 250,000 lines of code. I'm currently the only developer working on this application that was originally built in .NET 1.1. Pervasive throughout is a class that inherits from CollectionBase. All database collections inherit from this class. I am considering refactoring to inherit from the g...
From Wikipedia: Generic programming is a style of computer programming in which algorithms are written in terms of to-be-specified-later types that are then instantiated when needed for specific types provided as parameters and was pioneered by Ada which appeared in 1983. This approach permits writing common function...
That is, I'd like to have a tuple of values. The use case on my mind: Dictionary<Pair<string, int>, object> or Dictionary<Triple<string, int, int>, object> Are there built-in types like Pair or Triple? Or what's the best way of implementing it? Update There are some general-purpose tuples implementations described in the answers,...
Why isn't Collection.remove(Object o) generic? Seems like Collection<E> could have boolean remove(E o); Then, when you accidentally try to remove (for example) Set<String> instead of each individual String from a Collection<String>, it would be a compile time error instead of a debugging problem later. ...
I have a ArrayList made up of different elements imported from a db, made up of strings, numbers, doubles and ints. Is there a way to use a reflection type technique to find out what each type of data each element holds? FYI: The reason that there is so many types of data is that this is a piece of java code being written to be implem...
I noticed that you can call Queue.Synchronize to get a thread-safe queue object, but the same method isn't available on Queue<T>. Does anyone know why? Seems kind of weird. ...
I've got a generic<> function that takes a linq query ('items') and enumerates through it adding additional properties. How can I select all the properties of the original 'item' rather than the item itself (as the code below does)? So equivalent to the sql: select *, 'bar' as Foo from items foreach (var item in items) { var newIte...
I need to write a function that receives a property as a parameter and execute its getter. If I needed to pass a function/delegate I would have used: delegate RET FunctionDelegate<T, RET>(T t); void func<T, RET>(FunctionDelegate function, T param, ...) { ... return function.Invoke(param); } Is there a similar way to define a...