Audit the Current User or Host Identity

• May 06, 2021
• 2 minutes to read

If you build a business application that is intended for use by several end-users at the same time, you need to get information on who made a particular change. For this purpose, the CurrentUserName property of the application’s security system is passed to the Audit Trail system. If you do not use the XAF security system, handle the QueryCurrentUserName event to specify the user name for audit records. In an XAF Windows Forms application you can get the user name from the WindowsIdentity object. In an XAF ASP.NET Web application, you can use the value returned by the HttpContext.Current.Request.UserHostAddress property. The following code demonstrates how this can be implemented.

XAF Windows Forms Application - Program.cs (Program.vb) file:

C#

using System.Security.Principal;
//...
static void Main() {
    MySolutionWindowsFormsApplication application = new MySolutionWindowsFormsApplication();
    // ...
    //Subscribe to QueryCurrentUserName event of the AuditTrailService's instance
    AuditTrailService.Instance.QueryCurrentUserName += 
       new QueryCurrentUserNameEventHandler(Instance_QueryCurrentUserName);
    application.Setup();
    application.Start();
    //...
}
static void Instance_QueryCurrentUserName(object sender, QueryCurrentUserNameEventArgs e) {
    e.CurrentUserName = WindowsIdentity.GetCurrent().Name;
}

VB.NET

Imports System.Security.Principal
'...
Shared Sub Main()
    Dim _application As MySolutionWindowsFormsApplication = New MySolutionWindowsFormsApplication()
    '...
    'Subscribe to QueryCurrentUserName event of the AuditTrailService's instance
    AddHandler AuditTrailService.Instance.QueryCurrentUserName, _
    AddressOf Instance_QueryCurrentUserName
    _application.Setup()
    _application.Start()
    '...
End Sub
Shared Sub Instance_QueryCurrentUserName(ByVal sender As Object, _
ByVal e As QueryCurrentUserNameEventArgs)
    e.CurrentUserName = WindowsIdentity.GetCurrent().Name
End Sub

XAF ASP.NET Application - Global.asax.cs (Global.asax.vb) file:

C#

protected void Session_Start(object sender, EventArgs e) {
    WebApplication.SetInstance(Session, new MySolutionWebApplication());
    AuditTrailService.Instance.QueryCurrentUserName += 
        new QueryCurrentUserNameEventHandler(Instance_QueryCurrentUserName);
    //...
    WebApplication.Instance.Setup();
    WebApplication.Instance.Start();
}
private void Instance_QueryCurrentUserName(object sender, QueryCurrentUserNameEventArgs e) {
    e.CurrentUserName = 
        String.Format("Web user ({0})", HttpContext.Current.Request.UserHostAddress);
}

VB.NET

Protected Sub Session_Start(ByVal sender As Object, ByVal e As EventArgs)
    WebApplication.SetInstance(Session, New MainDemoWebApplication())
    AddHandler AuditTrailService.Instance.QueryCurrentUserName, _
    AddressOf Instance_QueryCurrentUserName    
    '...
    WebApplication.Instance.Setup()
    WebApplication.Instance.Start()
End Sub
Private Sub Instance_QueryCurrentUserName(ByVal sender As Object, _
ByVal e As QueryCurrentUserNameEventArgs)
    e.CurrentUserName = String.Format("Web user ({0})", HttpContext.Current.Request.UserHostAddress)
End Sub