Handy C# Knowledge

Intro

Just some things I have learnt when programming in the csharp language that didn’t make for a separate tutorial.

This will be updated when I learn new cool things in C#.

Keywords

Ref (Passing values by reference)

• A referenced local variable will not only effect the local variable but the variable from where it was passed.

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int a = 5;
AddOne(ref a);
Console.WriteLine(a);

public static void AddOne(ref int a)
{
    a += 1;
}

Out (passing variable by Ref & assigning a value to it)

• parameters are always passed by reference
• variable must only be initialized when calling with out
• variable can be initialized with the out keyword or outside separately

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GetMyInt(out int a);
Console.Write(a);

public static void GetMyInt(out int x)
{
    x = 10;
}

Useful things

Swapping variables

Extra variable

• requires extra variable to be defined

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int a = 4;
int b = 8;

int c = a;
int a = b;
int b = c

Tuples (C# 7.0)

• does not need extra variable defined
• more readable

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int a = 4;
int b = 8;

(a, b) = (b, a);

Compact Getters/Setters

Traditional

• can get messy when there are lots of getters and setters

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class MyClass
{
    private string myVar1 = "hello";
    public string MyVar1
    {
        get
        {
            return myVar1;
        }
    }
}

Compact 1

• supports both get and set

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class MyClassCompact
{
    private string myVar1 = "hello";
    public string MyVar1
    {
        get => myVar1;
    }
}

Compact 2

• only supports getter
• very clean (only uses one line)

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class MyClassCompact2
{
    private string myVar1 = "hello";
    public string MyVar1 => myVar1;
}

Auto Defined Private Fields

Traditional

• two variables are written
• looks neater when lots of fields defined

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class MyClass
{
    private string myVar1;
    public string MyVar1 => myVar1;
}

Compact

• no need to write another variable name
• private variable is still defined internally
• can still set variable inside class (acts as private)

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class MyClassCompact
{
    public string MyVar1 { get; private set; }
}