If Not EventLog.SourceExists("MyApp1") Then
    EventLog.CreateEventSource("MyApp1", "Application")
End If

        if (!System.Diagnostics.EventLog.SourceExists("MyApp1"))
            System.Diagnostics.EventLog.CreateEventSource(
               "MyApp1", "Application");

If Not EventLog.SourceExists("MyApp1", "myserver") Then
    Dim create As New EventSourceCreationData("MyApp1", "Application")
    create.MachineName = "myserver"
    EventLog.CreateEventSource(create)
End If

        EventSourceCreationData sourceData = new EventSourceCreationData("MyApp1", "Application");
        sourceData.MachineName = "myserver";
        if (!System.Diagnostics.EventLog.SourceExists("MyApp1", "myserver"))
            System.Diagnostics.EventLog.CreateEventSource(sourceData);