Yesterday I was thinking about whether it would be possible to use the convenience of C++0x lambda functions to write callbacks for Windows API functions. For example, what if I wanted to use a lambda as an EnumChildProc with EnumChildWindows? Something like: EnumChildWindows(hTrayWnd, CALLBACK [](HWND hWnd, LPARAM lParam) { //...
I have my own html helper extension, wich I use this way <%=Html.LocalizableLabelFor(model => model.Reason_ID, Register.PurchaseReason) %> which declared like this. public static MvcHtmlString LocalizableLabelFor<T>(this HtmlHelper<T> helper, Expression<Func<T, object>> expr, string captionValue) where T : class { return...
I read on the internet many tutorials that explained how to use lambdas with the standard library (such as std::find), and they all were very interesting, but I couldn't find any that explained how I can use a lambda for my own functions. For example: int main() { int test = 5; LambdaTest([&](int a) { test += a; }); return...
Hi All, I hope i'm missing something obvious, but I'm having some troubles defining a method that takes a parameter of a method to fetch the method information for the passed method. I do NOT want actually execute the method. I want to be able to do: busObject.SetResolverMethod<ISomeInterface>(x=>x.GetNameById); Where GetNameById ...
I have two samples of code. One works and returns the correct result, one throws a null reference exception. What's the difference? I know there's some magic happening with capturing variables for the lambda expression but I don't understand what's going on behind the scenes here. int? x = null; bool isXNull = !x...
I'm really interested how lambda functions are used. Does it make sense to use them in a modern, high-level programming language like php? If yes, why? Is this really just a function embedded in a function (like this) or is there more behind them? ...
I am learning scheme. I know how to use both lambda and let expressions. However I'm struggling to figure out what the point is of using lambda. Can't you do everything with let that you can with lambda? It would be especially helpful to see an example of a situation where a lambda expression is a better choice than let. One other thi...
Important update: Apparently I drew the wrong conclusion when I asked this question. Thanks to the responses I found out the lambda function [=]() does work fine in a multithreaded scenario. My apologies for posing this confusing question. Please vote to close, as it was a non-issue. In our company we've written a library function to ...
Let's look at the code, generated by F# for simple function: let map_add valueToAdd xs = xs |> Seq.map (fun x -> x + valueToAdd) The generated code for lambda expression (instance of F# functional value) will looks like this: [Serializable] internal class map_add@3 : FSharpFunc<int, int> { public int valueToAdd; internal ...
I am using the EventAgregator pattern to subscribe and publish events. If a user subscribes to the event using a lambda expression, they must use a strong reference, not a weak reference, otherwise the expression can be garbage collected before the publish will execute. I wanted to add a simple check in the DelegateReference so that if ...
There are a lot of such classes in my project (very old and stable code, I can't do many changes to them, maybe slight changes are OK) public class MyEntity { public long ID { get; set; } public string Name { get; set; } public decimal Salary { get; set; } public static GetMyEntity ( long ID ) { MyEntity e = new MyE...
hello. How come this is not allowed? lambda: print "x" is this not a single statement or something else? documentation is a little sparse on what allowed lambda is thank you ...
Hey, I'm not sure that silly question, but I ask: So, if there is an anonymous function I can give it as another anonymous functions parameter, if it has been already stored a variable. But, whats in that case, if I have stored only one function in a variable, and add the second directly as a parameter into it? Can I add parameters to t...
I'm new in C# and earlier I saw the lambda expression is like (params) => { expression;} but in LINQ, I saw examples like IEnumerable<string> customerFirstNames = customers.Select(cust => cust.FirstName); No brackets. Are they the same or is there any difference? Thanks a lot. ...
I have a class that extends the HtmlHelper in MVC and allows me to use the builder pattern to construct special output e.g. <%= Html.FieldBuilder<MyModel>(builder => { builder.Field(model => model.PropertyOne); builder.Field(model => model.PropertyTwo); builder.Field(model => model.PropertyThree); }) %> ...
I have two colluections List<Application> myApps; List<Application> yourApps; These lists have overlapping overlapping data but they are coming from different sources and each source has some missing field data. Application object has a property called Description Both collections have a unique field called Key i want to see if t...
I am trying to pass a lambda expression to a function that takes a function pointer, is this even possible? Here is some sample code, i'm using VS2010: #include <iostream> using namespace std; void func(int i){cout << "I'V BEEN CALLED: " << i <<endl;} void fptrfunc(void (*fptr)(int i), int j){fptr(j);} int main(){ fptrfunc(func,...
How, in C#, do I have a Func parameter representing a method with this signature? XmlNode createSection(XmlDocument doc, params XmlNode[] childNodes) I tried having a parameter of type Func<XmlDocument, params XmlNode[], XmlNode> but, ooh, ReSharper/Visual Studio 2008 go crazy highlighting that in red. Update: okay, Googling for 'c#...
I have the following methods: protected static void updateExistingSection(XmlDocument doc, XmlNode rootNode, string sectionTag, CreateSection createSection, Func<XmlNode[]> createChildNodes, Action<XmlNode> firstSection) { IEnumerable<XmlNode> sections = getChildNodesByName(rootNode, sectionTag); if (sections.Cou...