Мониторинг действий приложений

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim HWND As IntPtr = FindWindow(vbNullString, "iSendSMS - Отправка SMS/MMS сообщений")
        If HWND <> 0 Then
            Dim HGroupBox As IntPtr = FindWindowEx(HWND, 0, "TGroupBox", "Дополнительные параметры")
            If HGroupBox <> 0 Then
                Dim HComboBox As IntPtr = FindWindowEx(HGroupBox, 0, "TCheckBox", "Указать время доставки")
                If HComboBox <> 0 Then
                    SendMessage(HComboBox, WM_KEYDOWN, Keys.Space, 0)
                    SendMessage(HComboBox, WM_KEYUP, Keys.Space, 0)
                End If
            End If
        Else
            MsgBox("Окно не найдено!")
        End If
    End Sub

Public Class Form1
    <DllImport("user32.dll")>
    Public Shared Function GetComboBoxInfo(ByVal hWnd As IntPtr, ByRef pcbi As COMBOBOXINFO) As Boolean
    End Function
    <StructLayout(LayoutKind.Sequential)>
    Public Structure COMBOBOXINFO
        Public cbSize As Int32
        Public rcItem As Rectangle
        Public rcButton As Rectangle
        Public buttonState As ComboBoxButtonState
        Public hwndCombo As IntPtr
        Public hwndEdit As IntPtr
        Public hwndList As IntPtr
    End Structure
 
    Public Enum ComboBoxButtonState
        STATE_SYSTEM_NONE = 0
        STATE_SYSTEM_INVISIBLE = &H8000
        STATE_SYSTEM_PRESSED = &H8
    End Enum
 
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim cbi As COMBOBOXINFO
        cbi.cbSize = System.Runtime.InteropServices.Marshal.SizeOf(cbi)
        If GetComboBoxInfo(ComboBox1.Handle, cbi) Then
            '...
        End If
    End Sub
End Class

    Declare Auto Function SendMessage Lib "user32.dll" (ByVal hWnd As IntPtr, ByVal msg As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr
    Declare Function SendMessageByString Lib "user32.dll" Alias "SendMessageA" (ByVal hwnd As IntPtr, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As String) As Integer
    Function GetText(ByVal WindowHandle As IntPtr)
        Dim TextLen As Integer = SendMessage(WindowHandle, WM_GETTEXTLENGTH, 0, 0) + 1
        Dim Text As String = New String(" "c, TextLen)
        SendMessageByString(WindowHandle, WM_GETTEXT, TextLen, Text)
        Return Text
    End Function

<DllImport("user32.dll")> _
Private Shared Function IsWindowEnabled(ByVal hWnd As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
End Function