In interviews there is always the Singleton question, I personally refuse to answer it on interview. The reason is very simple I don’t code singletons anymore. I use my IoC Container to provide me with a singleton. Sorry if you dont know what an IoC (Inversion of Control Container) is, then you are still in […]
Tag: .net
C# has the as keyword, it is mainly used to cast object of one type to another, and if it fails it should return a null rather than crashing the program or throwing exception. From MSDN documentation it states: You can use the as operator to perform certain types of conversions between compatible reference types […]
So C# what is the yield keyword? The yield keyword in C# is basically an iterator, its a form of syntactic sugar added from C# 2.0 to create IEnumerable and IEnumerator objects, thus returning one element at a time. From MSDN documentation it states. When you use the yield keyword in a statement, you indicate […]
In C# if one wishes to use C# constructor overloading they can use the “this” keyword right after to initialize the object, the only thing to note is one will not be able to do any validation of the data using this method. Below I have listed 3 ways that one can initialize constructor overload […]
C# readonly what is that for? The readonly keyword in C# is used as a modifier. A field can be declared with readonly modifier, and its assignment can only be in the Constructor or when the variable is declared. An example:
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public readonly int MinAge = 10; //this is valid public class Person { public readonly int _age; public Person(int age) { _age = age; //this is also valid } public void SetAge(int age) { _age = age; //this is invalid, one cannot set it here would give compile error } public int Age { get { return _age; } //this is also valid no setter just getter } } |
The main thing to understand about readonly modifiers is that they are initialized […]
From the C# documentation it states that the @ symbol is an Identifier. 2.4.2 Identifiers The prefix “@” enables the use of keywords as identifiers, which is useful when interfacing with other programming languages. The character @ is not actually part of the identifier, so the identifier might be seen in other languages as a […]
C# Func vs. Action? What is the difference between a Func vs an Action in C#? The main difference is whether one wants the delegate to return a value or not. By using Func it will expect the delegate to return a value and Action for no value (void) 1. Func for methods that return […]
So sometimes you will get these strange errors or exceptions when using Linq Sequence contains no matching element For example if you use
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var result = myEnumerableCollection.First(x => x.Name == person.Name); |
This will throw InvalidOperationException with Sequence contains no matching element. But if you use
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var result = myEnumerableCollection.FirstOrDefault(x => x.Name == person.Name); if(result == null) //did not find in the collection something went wrong or ..... |
Which will return you a null if its not found then you can check if the […]
