MonitorEventHandler Delegate

In This Topic

Represents the method that will handle the TraceEvent event of the DbMonitor class.

Syntax

Visual Basic
C#

'Declaration
 
Public Delegate Sub MonitorEventHandler( _
   ByVal sender As Object, _
   ByVal e As MonitorEventArgs _
)

public delegate void MonitorEventHandler( 
   object sender,
   MonitorEventArgs e
)

Parameters

sender: The source of the event.
e: The MonitorEventArgs object that contains the event data.

Remarks

When you create a MonitorEventArgs delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event handler delegates, see "Events and Delegates" in the .NET Framework SDK documentation.

Example

The following sample shows how to enable and disable monitoring of database activity in your application.

csharp

static void OnEvent(object sender, MonitorEventArgs e)
{
  if (e.TracePoint==MonitorTracePoint.BeforeEvent)
  {
    Console.WriteLine("Description: " + e.Description);
    Console.WriteLine(" Extra info: " + e.ExtraInfo);
  }
}


[MTAThread]
static void Main(string[] args)
{
  SQLiteConnection sqConn = new SQLiteConnection(
      "DataSource=mydatabase.db;");
  SQLiteMonitor sqMonitor = new SQLiteMonitor();
  sqMonitor.TraceEvent += new MonitorEventHandler(OnEvent);
  sqMonitor.IsActive = true;
  SQLiteCommand sqCommand = new SQLiteCommand("select count(*) from Dept",sqConn);
  sqConn.Open();
  Console.WriteLine(sqCommand.ExecuteScalar());
  sqConn.Close();
  sqMonitor.TraceEvent -= new MonitorEventHandler(OnEvent);
  Console.ReadLine();
}

Visual Basic

Sub OnEvent(ByVal sender As Object, ByVal e As MonitorEventArgs)
  If e.TracePoint = MonitorTracePoint.BeforeEvent Then
    Console.WriteLine("Description: " & e.Description)
    Console.WriteLine(" Extra info: " & e.ExtraInfo)
  End If
End Sub

<MTAThread()> _
Sub Main()
  Dim sqConn As SQLiteConnection = New SQLiteConnection( _
      "DataSource=mydatabase.db;")
  Dim sqMonitor As SQLiteMonitor = New SQLiteMonitor
  AddHandler sqMonitor.TraceEvent, AddressOf OnEvent
  sqMonitor.IsActive = True
  Dim sqCommand As SQLiteCommand = New SQLiteCommand("select count(*) from Dept", sqConn)
  sqConn.Open()
  Console.WriteLine(sqCommand.ExecuteScalar())
  sqConn.Close()
  RemoveHandler sqMonitor.TraceEvent, AddressOf OnEvent
  Console.ReadLine()
End Sub

Reference

MonitorEventHandler Members
Devart.Common Namespace

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