I've written a simple SessionItem management class to handle all those pesky null checks and insert a default value if none exists. Here is my GetItem method: public static T GetItem<T>(string key, Func<T> defaultValue) { if (HttpContext.Current.Session[key] == null) { HttpContext.Current.Session[key] = defaultValue.Inv...
Hi, Sorry if this is basic but I was trying to pick up on .Net 3.5. Question: Is there anything great about Func<> and it's 5 overloads? From the looks of it, I can still create a similar delgate on my own say, MyFunc<> with the exact 5 overloads and even more. eg: public delegate TResult MyFunc<TResult>() and a combo of various overl...
Going from a lambda to an Expression is easy using a method call... public void GimmeExpression(Expression<Func<T>> expression) { ((MemberExpression)expression.Body).Member.Name; // "DoStuff" } public void SomewhereElse() { GimmeExpression(() => thing.DoStuff()); } But I would like to turn the Func in to an expression, only i...
Hi all, I was wondering if someone could explain what Func<int, string> is and how it is used with some clear examples. Thanks in advance ...
Does the "C" standard support something similar to __func__ for the function arguments' names? ...
All the examples I can find about Func<> and Action<> are simple as in the one below where you see how they technically work but I would like to see them used in examples where they solve problems that previously could not be solved or could be solved only in a more complex way, i.e. I know how they work and I can see they are terse and ...
In the below example, how can I easily convert eventScores to List<int> so that I can use it as a parameter for prettyPrint? Console.WriteLine("Example of LINQ's Where:"); List<int> scores = new List<int> { 1,2,3,4,5,6,7,8 }; var evenScores = scores.Where(i => i % 2 == 0); Action<List<int>, string> prettyPrint = (list, title) => { ...
Hello, I've got a method (fyi, I'm using c#), accepting a parameter of type "Func", let's say it's defined as such: MethodAcceptingFuncParam(Func<bool> thefunction); I've defined the function to pass in as such: public bool DoStuff() { return true; } I can easily call this as such: MethodAcceptingFuncParam(() => { return Do...
Hello, I have a numerical analysis program which for simplicity calculates an algorithm similar to: y = ax^3 + bx^2 + cx + d; I calculate the values of a,b,c,d at runtime and would like to pass the following equivalent as a Func<double, double>. Where I can set a value for X, and get Y. y = 12x^3 + 13x^2 + 14x + 15; Where 12,13,14...
In haskell it is posible to partially apply an infix function using sections, for instance given the infix function < (less than) one can partially apply any of the function's arguments: (5 <) , (< 5) In other words, in haskell we have the following shorthand notation: op :: a -> b -> c (`op` y) === \x -> x `op` y (x `op`) === \y -> x...
I'd like a method that has the following API: //get all users with a role of admin var users = myRepository.GetUsers(u => u.Role == Role.Admin); Will something like this work? IList<User> GetUsers(Func<User, bool> predicate) { var users = GetAllUsers(); return users.Where(predicate).ToList(); ...
Does anyone know why I can't call BeginInvoke / EndInvoke on Action and Func delegates in my Silverlight app? I keep getting a NotSupportedException. Is there a workaround? ...
I want to make an extension method which fills a stackpanel with buttons. In order to do this I have to pass in a mouse-click-handler. What type does the mouseClickHandler parameter have to be here? I know it's something like these but they all don't work: delegate Func<object, RoutedEventArgs> Action<> Code: public static void F...
Hi All, I have a constructor signature like this public NavigationLink(Func<String> getName, Func<UrlHelper, String> getURL, Func<bool> isVisible, IEnumerable<NavigationLink> subItems) Inside that constructor I am assigning the getName to a property of the containin...
public object MethodName(ref float y) { //method } How do I defined a Func delegate for this method? ...
Hey, I'm writing my func spec, and I was wondering if there are any good samples of a complete and well-written func spec? Like "This is a standard You're supposed to aspire to" type of spec. I know that Joel has a skeleteon of a func spec on his website, but I am looking for something more complete because I'm not of the appropriate am...
Hello, I've been seing Func<> for sometime now, and I've manage to avoid it (for now). But, now it looks like I can't dodge it forever. For instance, I tried Dynamic Linq, but almost everything was in terms of Func<>. I've tried one of my book (C# 2008/Deitel&Deitel) and also MSDN but I'm not getting it yet. They all jump straight in th...
I've been trying to make my way through this article: http://blogs.msdn.com/wesdyer/archive/2008/01/11/the-marvels-of-monads.aspx ... And something on page 1 made me uncomfortable. In particular, I was trying to wrap my head around the Compose<>() function, and I wrote an example for myself. Consider the following two Func's: Func<d...
I have a sample program, which needs to execute 3 methods in a particular order. And after executing each method, should do error handling. Now i did this in a normal fashion, w/o using delegates like this. class Program { public static void Main() { MyTest(); } private static bool MyTest() { ...
Hi, We're writing a web-based tool to configure our services provided by multiple servers. This includes interfaces configuration, dhcp configs etc. etc. Having configs in database and views that generate proper output, how to send it/make it available for servers? I'm thinking about sending it through scp and invoking reload command t...