Special component LinqMonitor is used for monitoring of the application interaction with database. It allows you to print trace messages to any output stream and use the dbMonitor tool for trace viewing. LinqMonitor offers you a possibility to monitor your database operations from DataContext. It can be used for any kind of applications – desktop, ASP.NET and windows services.

To start monitoring do the following steps:

• Create an instance of the LinqMonitor class
• Set the IsActive property to true
• Add the handler to the TraceEvent of the LinqMonitor class instance
• Use the Description and ExtraInfo properties of the MonitorEventArgs class to get an information about database operations

The following example shows you how to use LinqMonitor:

static void Main(string[] args)
{
     LinqMonitor linqMonitor = new LinqMonitor();
     linqMonitor.IsActive = true;
            
     CrmDemoContext.CrmDemoDataContext db = new CrmDemoContext.CrmDemoDataContext();
     linqMonitor.TraceEvent += new Devart.Data.Linq.Monitoring.MonitorEventHandler(OnEvent);
     var query = from it in db.Companies
                 select it;
            
     foreach (CrmDemoContext.Company company in query)
     {
         Console.WriteLine(company.CompanyName);
     }
 
     linqMonitor.TraceEvent -= OnEvent; 
}

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

Private Shared Sub Main(ByVal args As String())   
    Dim linqMonitor As New LinqMonitor
    linqMonitor.IsActive = True
    
    Dim db As New CrmDemoDataContext
    AddHandler linqMonitor.TraceEvent, New MonitorEventHandler(AddressOf Program.OnEvent)
    
    Dim query = From it in db.Companies
                Select it;
    
    Dim company As Company
    For Each company In query
        Console.WriteLine(company.CompanyName)
    Next
    
    RemoveHandler linqMonitor.TraceEvent, New MonitorEventHandler(AddressOf Program.OnEvent)
End Sub

Private Shared 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

The output of this sample is listed below:

Description: Open connection: "User ID=CRM_DEMO;Password=CRM_DEMO;SERVER=DB;"


Extra info: User ID=CRM_DEMO;Password=CRM_DEMO;SERVER=DB;;


Description: Execute: SELECT t1."CompanyID", t1."CompanyName", t1."PrimaryContact", 
t1."Web", t1."Email", t1."AddressTitle", t1."Address", t1."City", 
t1."Region", t1."PostalCode", t1."Country", t1."Phone", t1."Fax"
FROM CRM_DEMO."Company" t1


Extra info: -1


Borland UK CodeGear Division
Alpha Bank
...
Orderbase Consulting Gmbh


Description: Disconnect


Extra info: 

Monitoring capabilities are available at design-time as well. Just change the IsActive property to true and add a new handler on the Properties window.

Note:
Please note that the LinqMonitor doesn't support connection pool monitoring. To monitor connection pools install the Professional editions of the Devart data providers and use provider-specific monitors (OracleMonitor, MySqlMonitor, PgSqlMonitor, SQLiteMonitor).