linq-to-objects

This sound simple but it not that much. I want to order a List based on one of the properties of T, which is double type. If you know the propertyname before compilation: myList = myList.OrderBy(a=>a.propertyName).ToList(); or myList = (from m in myList order by m.propertyName).ToList(); If you don't have the property at compile time (e.g. dynamic sorting in a grid or something); try the following extension methods: static class OrderByExtender { public static IOrderedEnumerable<T> OrderBy<T>(this IEnumerable<T> collection, string key, string direction) { LambdaExpression sortLambda =

I have a problem where I want a group type to be strongly typed but if I do it doesn't group correctly. See the code below... using System; using System.Collections.Generic; using System.Linq; namespace ConsoleApplication35 { class Program { static void Main(string[] args) { List<Foo> foos = new List<Foo>(); foos.Add(new Foo() { Key = "Test" }); foos.Add(new Foo() { Key = "Test" }); foos.Add(new Foo() { Key = "Test" }); var groups = foos.GroupBy<Foo, dynamic>(entry => new { GroupKey = entry.Key }); Console.WriteLine(groups.Count()); groups = foos.GroupBy<Foo, dynamic>(entry => new GroupingKey(

I have two Generic Lists containing different types, for the sake of example, lets call them Products and Employees . I'm trying to find Products that are based at the same location as Employees, i.e. where product.SiteId == emp.SiteId List<Product> lstProds; List<Employees> lstEmps; My (old skool) brain is telling me to use a forEach loop to find the matches but I suspect there is a ('better'/terser/faster?) way to do it using Linq. Can anyone illuminate me? All the examples I've found online deal with Lists of primitives (strings/ints) and are not especially helpful. I would say: var

I'm developing an app in C# targeting .NET 3.5. In it, I have 2 similar dictionaries that contain validation criteria for a specific set of elements in my app. Both dictionaries have identical signatures. The first dictionary has the default settings and the 2nd dictionary contains some user defined settings. var default_settings = new Dictionary<string, MyElementSettings>(); var custom_settings = new Dictionary<string, MyElementSettings>(); I would like to combine the 2 dictionaries into one that contains the elements of both dictionaries. The problem that I am running into is it is possible

I'm a bit surprised to find the results of the following code, where I simply want to remove all 3s from a sequence of ints: var sequence = new [] { 1, 1, 2, 3 }; var result = sequence.SkipWhile(i => i == 3); // Oh noes! Returns { 1, 1, 2, 3 } Why isn't 3 skipped? My next thought was, OK, the Except operator will do the trick: var sequence = new [] { 1, 1, 2, 3 }; var result = sequence.Except(i => i == 3); // Oh noes! Returns { 1, 2 } In summary, Except removes the 3, but also removes non-distinct elements. Grr. SkipWhile doesn't skip the last element, even if it matches the condition. Grr.

Any advice on when DataTable.Select should be used versus LINQ Select when dealing with an in-memory DataTable? I find LINQ syntax easier and more powerful, but I'm not sure if there are performance or other issues which make a DataTable select preferable. (I'm using a third party API that provides a DataTable that has been pre-populated from the database. I need to filter that further in-memory.) Based upon personal experience, I try to avoid the Datatable.Select. I find it to be slow and has some odd bugs. One (confirmed and documented by Microsoft) bug I ran into was that DataTable.Select