Array C#

C# > Types > Array

An array is a data structure that contains a number of variables called the elements of the array.
C# arrays are zero indexed.
All of the array elements must be of the same type.
Array elements can be of any type, including an array type.

Single-Dimensional Arrays

int[] m_i = new int[3];

string[] m_s = new string[5];
int[] m_i = new int[] { 1, 2, 3 }; // Array Initialization

Multidimensional Arrays

int[,] m_i = new int[3,2]; // two-dimensional array of 3 rows and two columns:
int[,,] m_i_1 = new int [5,1,2]; //  array of three dimensions, 5, 1, 2
int[,] myArray = new  int[,] {{1,2}, {3,4}, {5,6} }; // Array Initialization

Jagged Arrays

A jagged array is an array whose elements are arrays. The elements of a jagged array can be of different dimensions and sizes.

int[][] m_j = new int[2][];

m_j[0] = new int[2];
m_j[1] = new int[3];

Loop all rows DataTable C#

C# > Data > DataTable > Loop all rows

foreach (DataRow row in DataTable1.Rows)
{
     m_v = row["ColName"].ToString();
}

HTTP (Hypertext Transfer Protocol)

HTTP (Hypertext Transfer Protocol) is the set of rules for transferring files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web.
When a user opens their Web browser, the user is indirectly making use of HTTP.
HTTP is an application protocol that runs on top of the TCP/IP protocols.

Find locked tables SQL Server

SQL Server > Dynamic Management Views and Functions > sys.dm_tran_locks

Returns information about currently active lock manager resources in SQL Server. Each row represents a currently active request to the lock manager for a lock that has been granted or is waiting to be granted.

Example:

Find locked tables SQL Server

select
   object_name(P.object_id) as TableName,
   resource_type,
   resource_description
from
   sys.dm_tran_locks L
   join sys.partitions P on L.resource_associated_entity_id = p.hobt_id

Static Constructors C#

C# > Class > static constructor

A static constructor is used to initialize any static data, or to perform a particular action that needs performed once only. It is called automatically before the first instance is created or any static members are referenced.

Static constructors have the following properties:

• A static constructor is called automatically to initialize the class before the first instance is created or any static members are referenced.

• A static constructor cannot be called directly.

• A typical use of static constructors is when the class is using a log file and the constructor is used to write entries to this file.

Example

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication2
{
     public class Log
    {
         // Static constructor:
         static Log()
        {
            System.Console.WriteLine("The static constructor invoked.");
         }
         public static void Write(string text)
        {
           System.Console.WriteLine("The Write method invoked.");
        }
   }
   class Program
   {
       static void Main(string[] args)
      {
          Log.Write("text"); // constructor invoked
          Log.Write("text"); // constructor not invoked.
      }
  }
}

protected C#

C# > Access Modifiers > Protected

The protected access modifier is between the private and public and is accessible from within the class in which it is declared, and from within any class derived from the class that declared this member.

Example:

namespace WFA

{

   public  class A

    {

        protected int x = 1;

        private int y;

    }

    public class B : A

    {

        B()

        {

            x = 2; // can access x, but cannot access y

            A a = new A();

            a.x = 1; // Error: Cannot access protected member 'WFA.A.x' via a qualifier of type 'WFA.A'; the qualifier must be of type 'WFA.B' (or derived from it)

        }

    }

Partial Class c#

C# > Class > Partial

Partial split the definition of a class over  more source files.
Each source file contains a section of the class definition, and all parts are combined when the application is compiled.

Use partial class when:

• working on large projects allows multiple programmers to work on it simultaneously.
• working with automatically generated source, code can be added to the class without having to recreate the source file.

Example

public partial class Car
{
      public int Year()
     {
      }
}

public partial class Car
{
      public void Go()
     {
      }
}