Class with events VB NET

VB.NET > Class > WithEvents

WithEvents specifies that one or more declared member variables refer to an instance of a class that can raise events.

Example: class with events

 Public Class Export
        Public Event TimesUp()
        Public Sub New()
            Dim worker As New BackgroundWorker()
            AddHandler worker.DoWork, AddressOf DoWork
            AddHandler worker.RunWorkerCompleted, AddressOf bg_RunWorkerCompleted
            worker.RunWorkerAsync()
        End Sub
        Private Sub DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs)
            ' export stuff
            Thread.Sleep(5000)
        End Sub
        Private Sub bg_RunWorkerCompleted(ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs)
            MsgBox("Background worker completed", vbInformation, "Background worker")
            RaiseEvent TimesUp() 'Triggers an event declared at module level within a class, form, or document.
        End Sub
    End Class

    Dim WithEvents _Export As New Export

    Private Sub handleTimesUp() Handles _Export.TimesUp
        MsgBox("TimesUp Event Raised and Handled")
    End Sub

 

BackgroundWorker VB.NET

VB.NET > BackgroundWorker

Executes an operation on a separate thread.

DoWork event occurs when RunWorkerAsync is called.
RunWorkerCompleted event occurs when the background operation has completed, has been canceled, or has raised an exception.

Example:

Imports System.ComponentModel

Imports System.Threading
Module Module1

  Public Sub backWork()
    Dim worker As New BackgroundWorker()
    AddHandler worker.DoWork, AddressOf DoWork
    AddHandler worker.RunWorkerCompleted, AddressOf bg_RunWorkerCompleted
    worker.RunWorkerAsync()
  End Sub

  Private Sub DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs)
    ' some work
    Thread.Sleep(5000)
  End Sub

  Private Sub bg_RunWorkerCompleted(ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs)
    MsgBox("Background worker completed", vbInformation, "Background worker")
  End Sub

End Module

ArrayList Class C#

C# > Collections > ArrayList

Implements the IList interface using an array whose size is dynamically increased as required.

Example

using System;
using System.Collections;
public class SampleArrayList  {

public static void Main()
{
   ArrayList m_l = new ArrayList();
   m_l.Add("a");
   m_l.Add("b");
   m_l.Add("c");
   m_l.Add(1);
   Console.WriteLine(" Count: {0}", m_l.Count);
   Console.WriteLine(" Capacity: {0}", m_l.Capacity);
   Console.Write( " Elements:" );
   PrintElements(m_l);
  }
  public static void PrintElements(IEnumerable m_l)
 {
    System.Collections.IEnumerator _enum = m_l.GetEnumerator();
    while (_enum.MoveNext())
           Console.Write("\t {0}", _enum.Current);
    Console.ReadLine ();
 }
}

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