Get Text From Specific Textboxes From External Application - Visual Basic .Net - vb.net

Question

I can get text from external application text box but now I want to get text from my desired text box from external application.
My English is not so good that's why see Image Below.
The Below Code Return The First Text Box Value Only.
Imports System.Runtime.InteropServices
Public Class Form1
Private Const WM_GETTEXT As Integer = &HD
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
<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function FindWindowEx(ByVal parentHandle As IntPtr, _
ByVal childAfter As IntPtr, _
ByVal lclassName As String, _
ByVal windowTitle As String) As IntPtr
End Function
Declare Auto Function FindWindow Lib "user32.dll" (ByVal lpClassName As String, ByVal lpWindowName As String) As IntPtr
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
'Find the running notepad window
Dim Hwnd As IntPtr = FindWindow(Nothing, TextBox1.Text)
'Alloc memory for the buffer that recieves the text
Dim Handle As IntPtr = Marshal.AllocHGlobal(100)
'send WM_GWTTEXT message to the notepad window
Dim NumText As Integer = SendMessage(Hwnd, WM_GETTEXT, 50, Handle)
'copy the characters from the unmanaged memory to a managed string
Dim Text As String = Marshal.PtrToStringUni(Handle)
'Display the string using a label
Label1.Text = Text
'Find the Edit control of the Running Notepad
Dim ChildHandle As IntPtr = FindWindowEx(Hwnd, IntPtr.Zero, "Edit", Nothing)
'Alloc memory for the buffer that recieves the text
Dim Hndl As IntPtr = Marshal.AllocHGlobal(200)
'Send The WM_GETTEXT Message
NumText = SendMessage(ChildHandle, WM_GETTEXT, 200, Hndl)
'copy the characters from the unmanaged memory to a managed string
Text = Marshal.PtrToStringUni(Hndl)
'Display the string using a label
Label2.Text = Text
End Sub
End Class

Answer 1

You'll have to loop through children of the main window (External Application) and get their properties.
You'll use the following:
<DllImport("User32.dll")> _
Public Function EnumChildWindows _
(ByVal WindowHandle As IntPtr, ByVal Callback As EnumWindowProcess, _
ByVal lParam As IntPtr) As Boolean
End Function
Public Delegate Function EnumWindowProcess(ByVal Handle As IntPtr, ByVal Parameter As IntPtr) As Boolean
Public Function GetChildWindows(ByVal ParentHandle As IntPtr) As IntPtr()
Dim ChildrenList As New List(Of IntPtr)
Dim ListHandle As GCHandle = GCHandle.Alloc(ChildrenList)
Try
EnumChildWindows(ParentHandle, AddressOf EnumWindow, GCHandle.ToIntPtr(ListHandle))
Finally
If ListHandle.IsAllocated Then ListHandle.Free()
End Try
Return ChildrenList.ToArray
End Function
For for details, check this How can I get properties of controls contained in a popup message box using VB.Net

Answer 2

' try this on excel vbe
External_application_handle=findwindow(vbNullString,"External_application")
textbox_1_handle=findwindowex(External_application_handle,0&,"Edit",vbNullString)
next_handle=textbox_1_handle
textbox_2_handle=findwindowex(External_application_handle,next_handle,"Edit",vbNullString")
Length = SendMessage(textbox_2_handle, WM_GETTEXTLENGTH, 0,0)
buffer$=space(Length)
call sendmessage(textbox_2_handle,Length+1,buffer$)
msgbox buffer