OleDB로 엑셀파일을 제어하는 툴을 만들었었는데,

MySheet$                                        // 내가 만든 Sheet

MySheet$_xlnm#_FilterDatabase        // 만들지도 않았고, 엑셀파일에서 보이지도 않음.

생각지도 못한 MySheet$_xlnm#_FilterDatabase 라는 Sheet Name이 뜨길래 뭔가 했는데 검색해보니 VB 관련으로 엑셀의 VBA를 쓰면 내부적으로 만들어서 사용하는 것 같다.

어쨌든 나에겐 필요없는 정보라서 Sheet Name에 "_FilterDatabase"가 포함되어 있으면 Skip하도록 소스를 조금 수정했다.

참조 : http://stackoverflow.com/questions/23034296/multi-sheet-import-with-oledb-netting-xlnm-filterdatabase-as-sheet-names

Google Protocol Buffer 사용해보기 with C# - 첫번째

Google Protocol Buffer 사용해보기 with C# - 세번째

Link : http://mrw0119.tistory.com/category/C%23

출처 : http://msdn.microsoft.com/ko-kr/library/bb397687.aspx

람다 식(C# 프로그래밍 가이드)

Visual Studio 2013

다른 버전

3명 중 3명이 도움이 되는 것으로 평가 - 이 항목 평가

delegate int del(int i);
static void Main(string[] args)
{
    del myDelegate = x => x * x;
    int j = myDelegate(5); //j = 25
}

using System.Linq.Expressions;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Expression<del> myET = x => x * x;
        }
    }
}

(input parameters) => expression

(x, y) => x == y

(int x, string s) => s.Length > x

() => SomeMethod()

(input parameters) => {statement;}

delegate void TestDelegate(string s);
…
TestDelegate myDel = n => { string s = n + " " + "World"; Console.WriteLine(s); };
myDel("Hello");

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private async void button1_Click(object sender, EventArgs e)
    {
        // ExampleMethodAsync returns a Task.
        await ExampleMethodAsync();
        textBox1.Text += "\r\nControl returned to Click event handler.\r\n";
    }

    async Task ExampleMethodAsync()
    {
        // The following line simulates a task-returning asynchronous process.
        await Task.Delay(1000);
    }
}

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        button1.Click += async (sender, e) =>
        {
            // ExampleMethodAsync returns a Task.
            await ExampleMethodAsync();
            textBox1.Text += "\r\nControl returned to Click event handler.\r\n";
        };
    }

    async Task ExampleMethodAsync()
    {
        // The following line simulates a task-returning asynchronous process.
        await Task.Delay(1000);
    }
}

public delegate TResult Func<TArg0, TResult>(TArg0 arg0)

Func<int, bool> myFunc = x => x == 5;
bool result = myFunc(4); // returns false of course

int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
int oddNumbers = numbers.Count(n => n % 2 == 1);

var firstNumbersLessThan6 = numbers.TakeWhile(n => n < 6);

var firstSmallNumbers = numbers.TakeWhile((n, index) => n >= index);

customers.Where(c => c.City == "London");

delegate bool D();
delegate bool D2(int i);

class Test
{
    D del;
    D2 del2;
    public void TestMethod(int input)
    {
        int j = 0;
        // Initialize the delegates with lambda expressions.
        // Note access to 2 outer variables.
        // del will be invoked within this method.
        del = () => { j = 10;  return j > input; };

        // del2 will be invoked after TestMethod goes out of scope.
        del2 = (x) => {return x == j; };
      
        // Demonstrate value of j:
        // Output: j = 0 
        // The delegate has not been invoked yet.
        Console.WriteLine("j = {0}", j);        // Invoke the delegate.
        bool boolResult = del();

        // Output: j = 10 b = True
        Console.WriteLine("j = {0}. b = {1}", j, boolResult);
    }

    static void Main()
    {
        Test test = new Test();
        test.TestMethod(5);

        // Prove that del2 still has a copy of
        // local variable j from TestMethod.
        bool result = test.del2(10);

        // Output: True
        Console.WriteLine(result);
           
        Console.ReadKey();
    }
}

public static class Extensions
{
    public static bool TryGetKey<K, V>(this IDictionary<K, V> instance, V value, out K key)
    {
        foreach (var entry in instance)
        {
            if (!entry.Value.Equals(value))
            {
                continue;
            }
            key = entry.Key;
            return true;
        }
        key = default(K);
        return false;
    }
}

the usage is also so simple

int key = 0;
if (myDictionary.TryGetKey("twitter", out key))
{
    // successfully got the key :)
}

Link : http://stackoverflow.com/questions/4001908/get-dictionary-key-by-using-the-dictionary-value

[참조] https://www.dotnetperls.com/extension

public class YourClass
{
    private readonly IDictionary<string, string> _yourDictionary = new Dictionary<string, string>();

    public string this[string key]
    {
        // returns value if exists
        get { return _yourDictionary[key]; }

        // updates if exists, adds if doesn't exist
        set { _yourDictionary[key] = value; }
    }
}

class SampleCollection<T>
{
    // Declare an array to store the data elements. 
    private T[] arr = new T[100];

    // Define the indexer, which will allow client code 
    // to use [] notation on the class instance itself. 
    // (See line 2 of code in Main below.)         
    public T this[int i]
    {
        get
        {
            // This indexer is very simple, and just returns or sets 
            // the corresponding element from the internal array. 
            return arr[i];
        }
        set
        {
            arr[i] = value;
        }
    }
}

// This class shows how client code uses the indexer. 
class Program
{
    static void Main(string[] args)
    {
        // Declare an instance of the SampleCollection type.
        SampleCollection<string> stringCollection = new SampleCollection<string>();

        // Use [] notation on the type.
        stringCollection[0] = "Hello, World";
        System.Console.WriteLine(stringCollection[0]);
    }
}
// Output: 
// Hello, World.

Link : http://msdn.microsoft.com/en-us/library/6x16t2tx.aspx

[추가]

Google NTP 주소 : time.google.com

[링크] https://developers.google.com/time/

C# - Simple Network Time (NTP) Protocol Client

SNTPClient.cs

Network Time Protocol (NTP) is a protocol for synchronizing the clocks of computer systems over packet-switched, variable-latency data networks. NTP uses UDP on port 123 as its transport layer. It is designed particularly to resist the effects of variable latency by using a jitter buffer. NTP also refers to a reference software implementation that is distributed by the NTP Public Services Project.

NTP is one of the oldest Internet protocols still in use (since before 1985). NTP was originally designed by Dave Mills of the University of Delaware, who still maintains it, along with a team of volunteers.

NTP is not related to the simpler DAYTIME (RFC 867) and TIME (RFC 868) protocols.

위키에서 가져옴-_-

경로 : http://en.wikipedia.org/wiki/Network_Time_Protocol

서버 따위에서 시간을 맞추기 위해서 사용하는 프로토콜이고 이런 시간 정보를 제공하는 서버를 타임 서버라고 많이들 이야길 하죠..

아래  ITS 는 아주 간단하게 구현되고 사용할 수 있지만 NTP 는 좀 까다롭습니다. -_-

그래서 괜히 어설프게 문서 만들고 예제 만들다간 욕 처먹을거 같아서 -.- 클래스 퍼온거 올려봅니다.

(원래는 간단하게 -_- 만들고 있었는데 제대로 된 소스를 발견해서 쪽팔려서 지움..;; -_- )

일단 아래는 활용 예제와 결과물입니다. 

출처 : http://www.devpia.com/Maeul/Contents/Detail.aspx?BoardID=18&MAEULNO=8&no=1770&page=11

링크 : http://www.pressblog.co.kr/linkblog/471319

출처 : http://msdn.microsoft.com/en-us/library/x53a06bb.aspx

C# Keywords

Visual Studio 2013

Other Versions

14 out of 17 rated this helpful - Rate this topic

Keywords are predefined, reserved identifiers that have special meanings to the compiler. They cannot be used as identifiers in your program unless they include @ as a prefix. For example, @if is a valid identifier but if is not because if is a keyword.

The first table in this topic lists keywords that are reserved identifiers in any part of a C# program. The second table in this topic lists the contextual keywords in C#. Contextual keywords have special meaning only in a limited program context and can be used as identifiers outside that context. Generally, as new keywords are added to the C# language, they are added as contextual keywords in order to avoid breaking programs written in earlier versions.

abstract	as	base	bool
break	byte	case	catch
char	checked	class	const
continue	decimal	default	delegate
do	double	else	enum
event	explicit	extern	false
finally	fixed	float	for
foreach	goto	if	implicit
in	in (generic modifier)	int	interface
internal	is	lock	long
namespace	new	null	object
operator	out	out (generic modifier)	override
params	private	protected	public
readonly	ref	return	sbyte
sealed	short	sizeof	stackalloc
static	string	struct	switch
this	throw	true	try
typeof	uint	ulong	unchecked
unsafe	ushort	using	virtual
void	volatile	while

Contextual Keywords

A contextual keyword is used to provide a specific meaning in the code, but it is not a reserved word in C#. Some contextual keywords, such as partial and where, have special meanings in two or more contexts.

add	alias	ascending
async	await	descending
dynamic	from	get
global	group	into
join	let	orderby
partial (type)	partial (method)	remove
select	set	value
var	where (generic type constraint)	where (query clause)
yield

See Also

Concepts

C# Programming Guide

Other Resources

C# Reference