Detect user inactivity (systemwide)

Imports System.Runtime.InteropServices

Public Class IdleTime

    Private Declare Function GetLastInputInfo Lib "User32.dll" _
      (ByRef lastInput As LASTINPUTINFO) As Boolean

    <structlayout(layoutkind.sequential)> _
    Public Structure LASTINPUTINFO
        Public cbSize As Int32
        Public dwTime As Int32
    End Structure


    Public ReadOnly Property IdleTime() As Integer

        Get

            Dim lastInput As New LASTINPUTINFO

            lastInput.cbSize = Marshal.SizeOf(lastInput)

            If GetLastInputInfo(lastInput) Then

                Return (Environment.TickCount - lastInput.dwTime) / 1000

            End If

        End Get

    End Property

End Class