nameof

问题 Let's say I have a ASP.NET Core 3.0 MVC application, which features a simple controller containing two actions and using attribute based routing: [Route("home")] public class HomeController : Controller { public static string ControllerName { get; } = "Home"; public HomeController() { } string GenerateUrls() { string url1 = Url.Action(nameof(Action1), ControllerName); string url2 = Url.Action(nameof(Action2Async), ControllerName); return $"Action1: '{url1}'\nAction2: '{url2}'"; } [HttpGet("a1

问题 Take the following class and method: public class Foo public Foo Create(string bar) { return new Foo(bar); } So getting "Create" is obvious: nameof(Foo.Create) Is there any way to get "bar" other than using reflection to read the parameters at run time? 回答1: No. There is no way to get the parameter names from the outside of the method using nameof . nameof doesn't work for method parameters if you want the name on the calling side (for the callee it does work obviously). The other methods you

问题 I'm in MonoDevelop v5.9.6. Although it seems to support C# 6.0, the editor doesn't recognize the nameof keyword, and it marks it red, because it tries to recognize it as if it were an identifier. Is there any hack I can use to make it work in the editor, without breaking the compilation somehow? 回答1: This hack works: // hack to make MonoDevelop recognize nameof syntax from C#6.0 using nameof = System.Func<string>; The editor recognizes it as "returning a string" and doesn't give any errors

问题 In my other question, I found a hack to make this syntax work in MonoDevelop editor: // hack to make MonoDevelop recognize nameof syntax from C#6.0 using nameof = System.Func<string>; The C# compilers (Mono and VS) don't give any warnings or errors, and usages of the nameof keyword also work normally. My question is why. 回答1: I'm not a language lawyer but I believe the reason your code works is that nameof is a contextual keyword Let's take a step back to a more general case. If you try to

问题 Ok, there's an existing question here on S/O with the following title: Swift: Get Variable Actual Name as String By it's name, it seems that's exactly what I want. However, looking at the accepted answer (and the other non-accepted ones), they are referring to key path manipulation, which isn't what I'm after. (i.e. This is not a duplicate!) In my case, I want the name of one variable to be stored in a second variable of type string. In C#, this is trivial using nameof , like so... int

问题 In relation to the question Get the name of parameters from a calling method and Finding the Variable Name passed to a Function in C# I'm still looking for a way to define the WhatDoesTheAnimalSay_WANTED method: I want to know the name of the variable that's used as a parameter: public class Farm { public readonly string Cow = "Muuuuhh"; public string Cat { get; set; } public void MainFunction() { var dog = "WauWau"; var kiwi = new Bird("QueeeekQueeek"); Cat = "Miiiaaauuuu"; // This one works

问题 In C# 6.0 you can write this: var instance = default(object); var type = typeof(object); They have the same result of: var instance = default(System.Object); var type = typeof(System.Object); But you can't write this: var name = nameof(object); It generates the following error: Invalid expression term 'object'. But you can still write this: var name = nameof(System.Object); Why nameof(object) does not compile? 回答1: The difference is that object is a synonym for the class Object and nameof()

问题 Is it possible to get the name of class's property (attention!) at compile time and without object instantiation? With instantiation it can easely be done with nameof(): class DummyClass { public int DummyProperty { get; set; } } void Meth() { //With instantiation var dc = new DummyClass(); var prname = nameof(dc.DummyProperty); } 回答1: You may use nameof(DummyClass.DummyProperty) , if I understood you correctly. There is a similar example for such a use case at docs. Used to obtain the simple

问题 It is a good idea to use nameof over expressions for extracting property names? //method with expression protected void RaisePropertyChanged<T>(Expression<Func<T>> propertyExpression, bool isValid, [param: Localizable(true)] string validationError) { string propertyName = PropertySupport.ExtractPropertyName(propertyExpression); RaisePropertyChanged(propertyName, isValid, validationError); } //the same logic without expression protected void RaisePropertyChanged(string propertyName, [param:

问题 To be clear, this is Not a duplicate of this question. Obviously, I can use the nameof operator to get the name of a variable or a parameter; I know that. But is there a way I can get the original name of a variable that's passed to a method? Currently, I have to do it like this: static void Foo(string someVariable, string variableName) { if (!FulfilsCondition(someVariable)) Console.WriteLine($"{variableName} is bad!"); // More code } And I call it like this: string bar = string.Empty; Foo