c#-6.0

I have two identical ASP.Net 4.6 MVC project, project 1 is using roslyn complier within the site which is working fine. c:\windows\system32\inetsrv>C:\Websites1\bin\roslyn\csc.exe Microsoft (R) Visual C# Compiler version 1.2.0.60325 With the second project I'm getting the error below, it's using the complier from .Net framework. c:\windows\system32\inetsrv> "C:\Windows\Microsoft.NET\Framework64\v4.0.30319\csc.exe" Microsoft (R) Visual C# Compiler version 4.6.1590.0 Line 6: @if (!Model?.Item?.IsDerived(Templates.PageMetadata.ID) ?? true) Line 7: { Line 8: return; c:\Website2\Views\metadata

I have started to use Interpolated Strings (new feature of C# 6) and it is really useful and gracefully. But according to my needs I have to pass format of string to a method as a parameter. Something like next: MyMethod(string format) In the past, I used it in the next way: MyMethod("AAA{0:00}") Now I tried this code: MyMethod($"AAA{i:00}") But this doesn't work, because i is created inside of the method and is out of scope in this context. Is it possible to use any trick for passing interpolated strings as a parameter to a method? You cannot do that, and that would not be a very good idea

What is the difference between the following expressions for initializing the properties in C# 6: 1. Auto-Property initialized from constructor public class Context1 { public Context1() { this.Items = new List<string>(); } public List<string> Items { get; private set; } } 2: Property initialized from a backing field public class Context2 { private readonly List<string> items; public Context2() { this.items = new List<string>(); } public List<string> Items { get { return this.items; } } } 3: Auto-Property new syntax in C# 6 public class Context3 { public List<string> Items { get; } = new List

With C# 6.0 I can do this var isEqual = x.Id == y.Id && x.UpdatedAt == y.UpdatedAt && x.Name == y.Name && x.RulesUrl == y.RulesUrl && x.OngoingChallenges?.Count == y.OngoingChallenges?.Count && x.MembershipIds?.Count == y.MembershipIds?.Count; Is there any nice solution to do this with C# < 6.0? I mean this part && x.OngoingChallenges?.Count == y.OngoingChallenges?.Count && x.MembershipIds?.Count == y.MembershipIds?.Count; Because in old projects we do not have possibility to use C# 6.0. How to write isEqual efficiently? x.OnGoingChallenges?.Count is equivalent to x.OnGoingChallenges != null ?

Using expression-bodied members allows you to define the body of a method or property as a single expression without a return keyword (should it return something). For example it turns these int Method1() { return 5; } void Method2() { Console.WriteLine(); } into these int Method1() => 5; void Method2() => Console.WriteLine(); A difference comes into play when you throw an exception from the body: void Method3() { throw new Exception(); } However, the following will not compile: void Method3() => throw new Exception(); with the following messages: Warning The member 'Program.Exception()' does

I have an unchanging dictionary that is exposed in a class. Currently my code looks like using System.Collections.Generic; using System.Collections.ObjectModel; public class FooClass { private static ReadOnlyDictionary<string, byte> _validRevisions = new ReadOnlyDictionary<string, byte>( new Dictionary<string, byte>() { { "1.0", 0x00 }, { "1.1", 0x01 }, { "1.2", 0x02 }, { "1.3", 0x03 } } ); public static ReadOnlyDictionary<string, byte> ValidRevisions => _validRevisions; // other FooClass contents... } I've used the backing field _validRevisions as I could not figure out a better way of

Are there cases when you would want a public readonly field v.s. a get-only auto-implemented property? public class Foo { public readonly string Hello; public string Hello2 { get; } } Both can only be set during the constructor and both offer readonly access outside of the class.. I'm a little tired so I might be missing something. PaulF One reason would be for data binding - .net implements binding to properties but not to public fields. Some discussion here : Why can't we use public fields for data binding in C#? Making it a property rather than a field means it can be used on interfaces.

Interpolated strings is one of the new features of C# 6.0. According to MSDN, the syntax of the embedded C# expressions can contain an optional, comma-separated value, deemed as <optional-comma-field-width> in the documentation . Unfortunately I didn't find what this field is for. From its name one might think that this value sets the maximal size of the "interpolated" field, but when I try the following expression: var p = Process.GetCurrentProcess(); Console.WriteLine($"Process name is {p.ProcessName, 5}"); I get the following output: Process name is LINQPad.UserQuery It's the minimum width