Public Class Form1
 
    Private Declare Function GetHandle Lib "dshandle" (ByVal Class1 As String, _
      ByVal Class2 As String, _
                ByVal Text1 As String, ByVal Text2 As String, Optional ByVal _
                Prop As Integer = 0, _
                Optional ByVal MatchClass As Integer = 0, Optional ByVal _
                MatchText As Integer = 0, _
                Optional ByVal hParent As Integer = 0, Optional ByVal _
                OnlyChildren As Integer = 0, _
                Optional ByVal IsChild As Integer = 0, Optional ByVal IsVisible _
                As Integer = 0, _
                Optional ByVal IsEnabled As Integer = 0, Optional ByVal Number _
                As Integer = 0, _
                Optional ByVal ThreadID As Integer = 0, Optional ByVal NotThrd _
                As Integer = 0, _
                Optional ByVal ProcID As Integer = 0, Optional ByVal NotProc As _
                Integer = 0) As Integer
 
    Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" _
                                        (ByVal parentHandle As IntPtr, _
                                         ByVal childAfter As IntPtr, _
                                         ByVal lclassName As String, _
                                         ByVal windowTitle As String) As IntPtr
 
    Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
                                        (ByVal hwnd As Integer, _
                                         ByVal wMsg As Integer, _
                                         ByVal wParam As Integer, _
                                         ByVal lParam As Integer) As Integer
 
    Private Declare Function SendMessageBystring Lib "user32" Alias _
      "SendMessageA" ( _
                                            ByVal hwnd As Integer, _
                                            ByVal wMsg As Integer, _
                                            ByVal wParam As Integer, _
                                            ByVal lParam As String) As Integer
 
    Private Const WM_GETTEXT As Integer = &HD
    Private Const WM_GETTEXTLENGTH As Integer = &HE
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
 
        Dim hwnd_calc As Integer = FindWindowEx(0, 0, "scicalc", vbNullString)
 
        If hwnd_calc > 0 Then
 
            For index As Int16 = 1 To 70
 
                Dim hwnd_button As Integer = 0
                hwnd_button = GetHandle("button", "", "*", "*", 0, 1, 1, _
                  hwnd_calc, 0, 0, 0, 0, index)
 
                Dim txtlen As Integer = 0
                txtlen = SendMessage(hwnd_button, WM_GETTEXTLENGTH, 0, 0) + 1
 
                Dim buttontext As String = ""
                buttontext = Space(txtlen)
 
                SendMessageBystring(hwnd_button, WM_GETTEXT, txtlen, buttontext)
 
                ListBox1.Items.Add("Button No. " + index.ToString + " Handle :" & _
                  "" + hwnd_button.ToString + " Text : " + buttontext)
 
            Next
 
        End If
 
    End Sub
 
End Class

Gruss mm78pr

http://msdn.microsoft.com/de-de/default.aspx