TraceEvent Event

In This Topic

Occurs when DbMonitor object signals about some database activity.

Syntax

Visual Basic
C#


'Declaration Public Event TraceEvent As MonitorEventHandler


public event MonitorEventHandler TraceEvent

Event Data

The event handler receives an argument of type MonitorEventArgs containing data related to this event. The following MonitorEventArgs properties provide information specific to this event.

Property	Description
CallStack	Gets the call stack of the monitor event.
Description	Gets the description of a DbMonitor event.
Duration	The time between the start and the end of the event.
EventType	Gets DbMonitor event type.
ExtraInfo	Gets the additional information for a DbMonitor event.
TracePoint	Determines whether TraceEvent event occurs before or after the operation takes place.

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) { MySqlConnection myConn = new MySqlConnection( "User Id=root;Host=localhost;Database=Test;"); MySqlMonitor myMonitor = new MySqlMonitor(); myMonitor.TraceEvent += new MonitorEventHandler(OnEvent); myMonitor.IsActive = true; MySqlCommand myCommand = new MySqlCommand("select count(*) from Dept",myConn); myConn.Open(); Console.WriteLine(myCommand.ExecuteScalar()); myConn.Close(); myMonitor.TraceEvent -= new MonitorEventHandler(OnEvent); Console.ReadLine(); }

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)
{
  MySqlConnection myConn = new MySqlConnection(
      "User Id=root;Host=localhost;Database=Test;");
  MySqlMonitor myMonitor = new MySqlMonitor();
  myMonitor.TraceEvent += new MonitorEventHandler(OnEvent);
  myMonitor.IsActive = true;
  MySqlCommand myCommand = new MySqlCommand("select count(*) from Dept",myConn);
  myConn.Open();
  Console.WriteLine(myCommand.ExecuteScalar());
  myConn.Close();
  myMonitor.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 myConn As MySqlConnection = New MySqlConnection( _ "User Id=root;Host=localhost;Database=Test;") Dim myMonitor As MySqlMonitor = New MySqlMonitor AddHandler myMonitor.TraceEvent, AddressOf OnEvent myMonitor.IsActive = True Dim myCommand As MySqlCommand = New MySqlCommand("select count(*) from Dept", myConn) myConn.Open() Console.WriteLine(myCommand.ExecuteScalar()) myConn.Close() RemoveHandler myMonitor.TraceEvent, AddressOf OnEvent Console.ReadLine() End Sub

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 myConn As MySqlConnection = New MySqlConnection( _
      "User Id=root;Host=localhost;Database=Test;")
  Dim myMonitor As MySqlMonitor = New MySqlMonitor
  AddHandler myMonitor.TraceEvent, AddressOf OnEvent
  myMonitor.IsActive = True
  Dim myCommand As MySqlCommand = New MySqlCommand("select count(*) from Dept", myConn)
  myConn.Open()
  Console.WriteLine(myCommand.ExecuteScalar())
  myConn.Close()
  RemoveHandler myMonitor.TraceEvent, AddressOf OnEvent
  Console.ReadLine()
End Sub

Reference

DbMonitor Class
DbMonitor Members

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