Database Connection state change event : Collection « Data Structure « VB.Net

Database Connection state change event

Database Connection state change event
Imports System
Imports System.Data
Imports System.Data.SqlClient

public class MainClass
   Shared Sub Main()
      Dim thisConnection As New SqlConnection("server=(local)\SQLEXPRESS;" & _
          "integrated security=sspi;database=MyDatabase")

      ' Sql Query
      Dim sql As String = "SELECT FirstName, LastName From Employee"

      ' Create command
      Dim thisCommand As New SqlCommand(sql, thisConnection)

      ' Add second handler to StateChange event
      AddHandler thisConnection.StateChange, AddressOf StateIsChanged


         ' Open connection and fire two statechange events

         ' Create datareader
         Dim thisReader As SqlDataReader = thisCommand.ExecuteReader()

         ' Display rows in event log
         While thisReader.Read()
            Console.WriteLine(thisReader.GetString(0) _
               + "-" + thisReader.GetString(1))
         End While
      Catch ex As SqlException
         ' Remove second handler from StateChange event
         RemoveHandler thisConnection.StateChange, AddressOf StateIsChanged

         ' Close connection and fire one StateChange event
      End Try
   End Sub
   Shared Private Sub StateIsChanged(ByVal sender As Object, ByVal e As System.Data.StateChangeEventArgs)
      ' Event handler for the StateChange Event
      Console.WriteLine("Entering Second StateChange EventHandler")
      Console.WriteLine("Sender = " + sender.ToString())
      Console.WriteLine("Original State = " + e.OriginalState.ToString())
      Console.WriteLine("Current State = " + e.CurrentState.ToString())
      Console.WriteLine("Exiting Second StateChange EventHandler")
   End Sub

End Class


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