CSharp

#region CmdLineStuff
......
#endregion CmdLineStuff

using System;

namespace HelloWorld
{
    class Program
    {
        private static void Main()
        {
            Console.WriteLine("Hello, world!");
        }
    }
}

string name = "Mark";
var date = DateTime.Now;

// Composite formatting:
Console.WriteLine("Hello, {0}! Today is {1}, it's {2:HH:mm} now.", name, date.DayOfWeek, date);
// String interpolation:
Console.WriteLine($"Hello, {name}! Today is {date.DayOfWeek}, it's {date:HH:mm} now.");
// Both calls produce the same output that is similar to:
// Hello, Mark! Today is Wednesday, it's 19:40 now.

Console.Write($"{aDoubleValue:f2}");

catch (InvalidCastException e) when (e.Data != null)
{
    // Take some action.
}

public interface CallbackInterface
{
    void OnRhythmComplete(int successCount, int failureCount, int readyCount);
    void OnRhythmChangeCursor(int measureNumber, int beatNumber, float progressPercentage);
}

public abstract class BaseElementInterface
{
    public abstract void OpenAttributeImpl(Xml.XmlNode node);
    public abstract void OpenElementImpl(Xml.XmlNode node);
    public abstract void ClearImpl();

    public abstract string ToPrintableText();
    public abstract string ToParamsText();
}

public int this[int key]
{
    get => GetValue(key);
    set => SetValue(key, value);
}

private Variant _Get(string section, string key, Variant @default = default /* `new Variant()` 와 동일하다. */ )
{
    return _config.GetValue(section, key, @default);
}

public enum Colors { None=0, Red = 1, Green = 2, Blue = 4 };
// ...
Colors colorValue = (Colors) Enum.Parse(typeof(Colors), colorString, true);

string filename = "C:\\Temp\\1.txt";

// @심벌을 사용하여 보다 자연스럽게 패스 지정
string filename = @"C:\Temp\1.txt";

// 여러 줄도 가능하다:
string code = @"
public string ReadFile(string filename)
{
    if (!string.IsNullOrEmpty(filename))
    {
        return File.ReadAllText(filename);
    }
    return string.Empty;
}
";

Console.WriteLine(code);

public void Run()
{
    // object라는 변수명 지정
    string @object = "객체";

    @object = @object + "1";
    Console.WriteLine(@object);
}

// ASP.NET MVC Html Helper
@Html.ActionLink("Goto Menu", "Menu", null,
     new { @class="linkStyle", target="_blank"});

<A href="/Home/Menu" class="linkStyle" target="_blank">
   Goto Menu
</A>

public string MyProp { get; } = "You cannot change me";

private readonly string myProp = "You cannot change me"
public string MyProp { get { return myProp ; } }

public string MyProp { get; }
protected MyClass(string myProp, ...)
{
    this.MyProp = myProp;
    ...
}

private readonly string myProp;
public string MyProp { get { return myProp; } }
protected MyClass(string myProp, ...)
{
    this.myProp = myProp;
    ...
}

Enumerable.Range(1, 10).Select(x => x + 2);

Enumerable.Range(1, 10).Aggregate(0, (acc, x) => acc + x);

Enumerable.Range(1, 10).Where(x => x % 2 == 0);

import System.IO;

// ...

foreach (string file in Directory.EnumerateFiles(path, "*.*", SearchOption.AllDirectories))
{
    Console.WriteLine(file);
}

static void DirSearch(string sDir)
{
    try
    {
        foreach (string d in Directory.GetDirectories(sDir))
        {
            foreach (string f in Directory.GetFiles(d))
            {
                Console.WriteLine(f);
            }
            DirSearch(d);
        }
    }
    catch (System.Exception excpt)
    {
        Console.WriteLine(excpt.Message);
    }
}

FolderBrowserDialog fbd = new FolderBrowserDialog();
if (fbd.ShowDialog() == DialogResult.OK)
{
    // ...
}

public void ChooseFolder()
{
    if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
    {
        textBox1.Text = folderBrowserDialog1.SelectedPath;
    }
}

public class CreateFileOrFolder
{
    static void Main()
    {
        // Specify a name for your top-level folder.
        string folderName = @"c:\Top-Level Folder";

        // To create a string that specifies the path to a subfolder under your
        // top-level folder, add a name for the subfolder to folderName.
        string pathString = System.IO.Path.Combine(folderName, "SubFolder");

        // You can write out the path name directly instead of using the Combine
        // method. Combine just makes the process easier.
        string pathString2 = @"c:\Top-Level Folder\SubFolder2";

        // You can extend the depth of your path if you want to.
        //pathString = System.IO.Path.Combine(pathString, "SubSubFolder");

        // Create the subfolder. You can verify in File Explorer that you have this
        // structure in the C: drive.
        //    Local Disk (C:)
        //        Top-Level Folder
        //            SubFolder
        System.IO.Directory.CreateDirectory(pathString);

        // Create a file name for the file you want to create.
        string fileName = System.IO.Path.GetRandomFileName();

        // This example uses a random string for the name, but you also can specify
        // a particular name.
        //string fileName = "MyNewFile.txt";

        // Use Combine again to add the file name to the path.
        pathString = System.IO.Path.Combine(pathString, fileName);

        // Verify the path that you have constructed.
        Console.WriteLine("Path to my file: {0}\n", pathString);

        // Check that the file doesn't already exist. If it doesn't exist, create
        // the file and write integers 0 - 99 to it.
        // DANGER: System.IO.File.Create will overwrite the file if it already exists.
        // This could happen even with random file names, although it is unlikely.
        if (!System.IO.File.Exists(pathString))
        {
            using (System.IO.FileStream fs = System.IO.File.Create(pathString))
            {
                for (byte i = 0; i < 100; i++)
                {
                    fs.WriteByte(i);
                }
            }
        }
        else
        {
            Console.WriteLine("File \"{0}\" already exists.", fileName);
            return;
        }

        // Read and display the data from your file.
        try
        {
            byte[] readBuffer = System.IO.File.ReadAllBytes(pathString);
            foreach (byte b in readBuffer)
            {
                Console.Write(b + " ");
            }
            Console.WriteLine();
        }
        catch (System.IO.IOException e)
        {
            Console.WriteLine(e.Message);
        }

        // Keep the console window open in debug mode.
        System.Console.WriteLine("Press any key to exit.");
        System.Console.ReadKey();
    }
    // Sample output:

    // Path to my file: c:\Top-Level Folder\SubFolder\ttxvauxe.vv0

    //0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
    //30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56
    // 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 8
    //3 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
}

private object lockObject = new object();
// ...
lock (lockObject)
{
    // ...
}

// ...
    public string GetIdentificationText()
    {
        using (MemoryStream stream = new MemoryStream())
        {
            using (StreamWriter writer = new StreamWriter(stream))
            {
                writer.WriteLine("[Identification]");
                foreach (var right in _scorePartwise.Identification.Rights)
                {
                    writer.WriteLine($"- Right: {right.Value}");
                }

                var encoding = _scorePartwise.Identification.Encoding;
                foreach (var encoder in encoding.Encoder)
                {
                    writer.WriteLine($"- Encoder: {encoder.Value}");
                }
                foreach (var encodingDate in encoding.EncodingDate)
                {
                    writer.WriteLine($"- Encoding Date: {encodingDate}");
                }
                foreach (var encodingDescription in encoding.EncodingDescription)
                {
                    writer.WriteLine($"- Encoding Description: {encodingDescription}");
                }
                foreach (var software in encoding.Software)
                {
                    writer.WriteLine($"- Software: {software}");
                }
                foreach (var supports in encoding.Supports)
                {
                    var e = supports.Element;
                    var t = supports.Type;
                    var v = supports.Value;
                    var a = supports.Attribute;
                    writer.WriteLine($"- Software: element={e}, type={t}, value={v}, attribute={a}");
                }
            }
            return System.Text.Encoding.UTF8.GetString(stream.ToArray());
        }
    }
// ...

// Two-dimensional array.
int[,] array2D = new int[,] { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };
// The same array with dimensions specified.
int[,] array2Da = new int[4, 2] { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };
// A similar array with string elements.
string[,] array2Db = new string[3, 2] { { "one", "two" }, { "three", "four" },
                                        { "five", "six" } };

// Three-dimensional array.
int[, ,] array3D = new int[,,] { { { 1, 2, 3 }, { 4, 5, 6 } }, 
                                 { { 7, 8, 9 }, { 10, 11, 12 } } };
// The same array with dimensions specified.
int[, ,] array3Da = new int[2, 2, 3] { { { 1, 2, 3 }, { 4, 5, 6 } }, 
                                       { { 7, 8, 9 }, { 10, 11, 12 } } };

for (int i = 0; i < array3D.Rank; i++) {
    total *= array3D.GetLength(i);
}

int[,] array2Da = new int[4, 2] { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };
array2Da.GetLength(0); // Return 4
array2Da.GetLength(1); // Return 2

Random r = new Random();
r.Next(); // 랜덤값 생성
r.Next(Int32 min, Int32 max); // 최소 min 값 부터 최대 max - 1 까지