Tutorial by Examples: od

Extension methods were introduced in C# 3.0. Extension methods extend and add behavior to existing types without creating a new derived type, recompiling, or otherwise modifying the original type. They are especially helpful when you cannot modify the source of a type you are looking to enhance. Ex...

Extension methods can also be used like ordinary static class methods. This way of calling an extension method is more verbose, but is necessary in some cases. static class StringExtensions { public static string Shorten(this string text, int length) { return text.Substring(0, ...

Expression-bodied function members allow the use of lambda expressions as member bodies. For simple members, it can result in cleaner and more readable code. Expression-bodied functions can be used for properties, indexers, methods, and operators. Properties public decimal TotalPrice => Base...

Declaration: void MyGenericMethod<T1, T2, T3>(T1 a, T2 b, T3 c) { // Do something with the type parameters. } Invocation: There is no need to supply type arguements to a genric method, because the compiler can implicitly infer the type. int x =10; int y =20; string z = "tes...

Get Instance method and invoke it using System; public class Program { public static void Main() { var theString = "hello"; var method = theString .GetType() .GetMethod("Substring", ...

Returns a new dictionary from the source IEnumerable using the provided keySelector function to determine keys. Will throw an ArgumentException if keySelector is not injective(returns a unique value for each member of the source collection.) There are overloads which allow one to specify the value t...

string sqrt = "\u221A"; // √ string emoji = "\U0001F601"; // 😁 string text = "\u0022Hello World\u0022"; // "Hello World" string variableWidth = "\x22Hello World\x22"; // "Hello World"

public class SomeClass { public void DoStuff() { } protected void DoMagic() { } } public static class SomeClassExtensions { public static void DoStuffWrapper(this SomeClass someInstance) { someInstance.DoStuff(); // ok ...

List<int> l2 = l1.FindAll(x => x > 6); Here x => x > 6 is a lambda expression acting as a predicate that makes sure that only elements above 6 are returned.

Visual Studio helps manage user and application settings. Using this approach has these benefits over using the appSettings section of the configuration file. Settings can be made strongly typed. Any type which can be serialized can be used for a settings value. Application settings can be...

var collection = new BlockingCollection<int>(5); var random = new Random(); var producerTask = Task.Run(() => { for(int item=1; item<=10; item++) { collection.Add(item); Console.WriteLine("Produced: " + item); Thread.Sleep(random.Next(1...

When passing formal arguments to a generic method, relevant generic type arguments can usually be inferred implicitly. If all generic type can be inferred, then specifying them in the syntax is optional. Consider the following generic method. It has one formal parameter and one generic type paramet...

Every method has a unique signature consisting of a accessor (public, private, ...) ,optional modifier (abstract), a name and if needed method parameters. Note, that the return type is not part of the signature. A method prototype looks like the following: AccessModifier OptionalModifier ReturnTyp...

Calling a static method: // Single argument System.Console.WriteLine("Hello World"); // Multiple arguments string name = "User"; System.Console.WriteLine("Hello, {0}!", name); Calling a static method and storing its return value: string input = System.Con...

Just like other methods, extension methods can use generics. For example: static class Extensions { public static bool HasMoreThanThreeElements<T>(this IEnumerable<T> enumerable) { return enumerable.Take(4).Count() > 3; } } and calling it would be like: ...

Many LINQ functions both operate on an IEnumerable<TSource> and also return an IEnumerable<TResult>. The type parameters TSource and TResult may or may not refer to the same type, depending on the method in question and any functions passed to it. A few examples of this are public stat...

Given an async method like this: Task<string> GetNameAsync(CancellationToken cancellationToken) Wrap it as an IObservable<string> like this: Observable.FromAsync(cancellationToken => GetNameAsync(cancellationToken))

The following examples will not compile: string s = "\c"; char c = '\c'; Instead, they will produce the error Unrecognized escape sequence at compile time.

Product flavors are defined in the build.gradle file inside the android { ... } block as seen below. ... android { ... productFlavors { free { applicationId "com.example.app.free" versionName "1.0-free" } paid { ...

Dependencies can be added for a specific product flavor, similar to how they can be added for specific build configurations. For this example, assume that we have already defined two product flavors called free and paid (more on defining flavors here). We can then add the AdMob dependency for the ...