parameter-passing | 易学教程

Parameter passing with initWithNibName:

阅读更多关于 Parameter passing with initWithNibName:

问题 In iphone Application I need to pass some values to a new viewcontroller object while it create from a method in another viewcontroller class so I can initialize that values in (id)initWithNibName:method of new viewcontroller then I can load those values in viewdidLoad method. what I want to know is how do I pass the values(parameters) to the constructor(initWithNibName) of a new viewcontrollor Object like constructor overloading in java give me some code example just showing how

Rails 4 - Pundit, Scopes: Getting Started

阅读更多关于 Rails 4 - Pundit, Scopes: Getting Started

I am really struggling in my efforts over the past 2+ years to try to learn how to use pundit. I am trying to write scoped policies, so that different users can receive objects based on the scope class that they fit into. I have asked several questions on the same topic previously, but I'm not getting any closer to a solution. My recent questions are: here , here , here , here , here and here . There are several others but these give the general picture, that I am struggling with the fundamentals of how to get started. I have a million problems with getting started and realise that after 4

How to best fake keyword style function arguments in Rust?

阅读更多关于 How to best *fake* keyword style function arguments in Rust?

问题 I'm interested to have something functionally similar to keyword arguments in Rust, where they're currently not supported. For languages that provide keyword argument, something like this is common: panel.button(label="Some Button") panel.button(label="Test", align=Center, icon=CIRCLE) I've seen this handled using the builder-pattern, eg: ui::Button::new().label("Some Button").build(panel) ui::Button::new().label("Test").align(Center).icon(CIRCLE).build(panel) Which is fine but at times a

When not to use std::forward with r-values?

阅读更多关于 When not to use std::forward with r-values?

问题 What are the cases when std::forward is not needed? It is used to wrap inner function argument which is templated-rvalue (that is, it can be lvalue or named-rvalue). Like in: template<class T> void outer(T&& t) { inner(std::forward<T>(t)); } I am guessing one case is when inner function parameters are passed by value. Are there other cases? I've got this question when I was writing std::begin(std::forward<Ct>(ct)) where Ct is templated-rvalue-ref. EDIT about possible duplicate If I remember

Passing single value to params argument in NUnit TestCase

阅读更多关于 Passing single value to params argument in NUnit TestCase

问题 I have the following test: [ExpectedException(typeof(ParametersParseException))] [TestCase("param1")] [TestCase("param1", "param2")] [TestCase("param1", "param2", "param3", "optParam4", "optParam5", "some extra parameter")] public void Parse_InvalidParametersNumber_ThrowsException(params string[] args) { new ParametersParser(args).Parse(); } The first TestCase (obviously) fails with the following error: System.ArgumentException : Object of type 'System.String' cannot be converted to type

Create insert function of any record type in Delphi XE7?

阅读更多关于 Create insert function of any record type in Delphi XE7?

问题 I have an record type for each Table in SQL Server. So when I want to insert (or update) a record on table I define a function to do so. Each field in delphi record has equivalent field in SQL table (with exact same name an type). It is too interesting to me to write a function to do this ( for example Inserting) for all record types using Retti. I mean a function that have a parameter for receive any record and creates insert query. I searched a lot and asked this question but finally not

How to pass by reference in Ruby?

阅读更多关于 How to pass by reference in Ruby?

问题 Currently I'm developing a Watcher class in Ruby, which, among other things, is able to find the period duration of a toggling signal. This is in general rather simple, but a problem I'm facing is that apparently Ruby passes all parameters by value. While researching online I found many different discussions about what "pass by value" and "pass by reference" actually is, but no actual "how to". Coming from a C/C++ background, for me this is an essential part of a programming/scripting

How do I pass a string value from a TextBox between Forms?

阅读更多关于 How do I pass a string value from a TextBox between Forms?

问题 I have two forms: Form1 which is my app and Form2 which is a login page. I want to pass a value entered into the username textbox (LoginTbox) on Form2 to Form1. This is what I have so far. No error is received, but it seems to be passing nothing. I've tried constructors, but couldn't seem to get that to work either. What am i doing wrong? Program.cs static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Form2 fLogin = new Form2(); if

What does map(&:name) mean in Ruby?

阅读更多关于 What does map(&:name) mean in Ruby?

问题 I found this code in a RailsCast: def tag_names @tag_names || tags.map(&:name).join(' ') end What does the (&:name) in map(&:name) mean? 回答1: It's shorthand for tags.map(&:name.to_proc).join(' ') If foo is an object with a to_proc method, then you can pass it to a method as &foo , which will call foo.to_proc and use that as the method's block. The Symbol#to_proc method was originally added by ActiveSupport but has been integrated into Ruby 1.8.7. This is its implementation: class Symbol def

passing a parameter pack over a legacy function signature using forward_as_tuple

阅读更多关于 passing a parameter pack over a legacy function signature using forward_as_tuple

问题 In my app I would like to pass in a parameter pack over a legacy function signature, and change the values. Here is code that illustrates my question with my attempts as comments: #include <tuple> #include <cassert> void LegacySignature( void* param ); template< typename... ArgsT > // using ???; // attempt: can 'template alias' or 'using declaration' make the pack's type visible so I can use it inside the LegacyFunction? void MyFunc( ArgsT&... args ) { auto userArgsTuple = std::forward_as