Solved

If I have the hWnd of a textbox how do I get it's text?

Posted on 2004-04-19
7
555 Views
Last Modified: 2006-11-17
I use API, But I don't know how to get the text from a text box using API. Can someone help me? I can get the hWnd or ID of the textbox or any window or control, but what is the function to extract the text from a textbox? Thanks for your help.
0
Comment
Question by:rcherne1
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
  • 2
  • +1
7 Comments
 
LVL 19

Expert Comment

by:BrianGEFF719
ID: 10863979
       
Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long

Public Const WM_GETTEXT = &HD



code:
        dim buffer as string

        Buffer = String(255, Chr(0))
        SendMessage hwnd, WM_GETTEXT, 255, Buffer
        Buffer = Left(Buffer, InStr(1, Buffer, Chr(0)) - 1)
0
 

Author Comment

by:rcherne1
ID: 10864334
BrianGEFF719,

         I make a new projet and put two textboxes on a form, Then I drop this code in. The only thing I get is a crash of the app. What am I doing wrong?



Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Const WM_GETTEXT = &HD

Private Sub Form_Load()
    Dim Txt1_hWnd As Long
    Txt1_hWnd = Text1.hwnd
    Text1.Text = "This is a text"

    'Your Code
              Dim buffer As String
              buffer = String(255, Chr(0))
              Call SendMessage(Txt1_hWnd, WM_GETTEXT, 255, buffer)
              buffer = Left(buffer, InStr(1, buffer, Chr(0)) - 1)
    'End Your Code

    Text2.Text = buffer
End Sub
0
 
LVL 19

Expert Comment

by:BrianGEFF719
ID: 10864350
I dont think you can do it from your own program, try a different text box that is not owned by your application.


-Brian
0
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 

Author Comment

by:rcherne1
ID: 10864450
Actually, that’s exactly what I’m trying to do. I used the code only to simplify the problem. Can you write an example that will work? I’m changing the points to 500 because I feel this is more challenging than I first though.
0
 
LVL 15

Accepted Solution

by:
unknown_routine earned 500 total points
ID: 10864640
Hi

Use this :


Option Explicit

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Integer, ByVal lParam As Any) As Long
Private Const WM_GETTEXT = &HD
Private Const WM_GETTEXTLENGTH = &HE


Private Sub Command1_Click()
    Dim n As Integer
 s As String
 q As Integer
s$ = Space$(255)
Dim k1, k2 As Long
n = SendMessage(Text1.hwnd, WM_GETTEXTLENGTH, k1, k2)
q = SendMessage(Text1.hwnd, WM_GETTEXT, 254, s$)
 s = Left(s, n)
 MsgBox s
End Sub

0
 
LVL 15

Expert Comment

by:unknown_routine
ID: 10864649
I forgot to put dims for 2 lines: add dims !


Dim s As String
Dim  q As Integer
0
 

Expert Comment

by:GentooJava
ID: 11011319
OMG!!!

It took me a couple of hours to find out why this example code crashes!
Change the following line:
     q = SendMessage(Text1.hwnd, WM_GETTEXT, 254, s$)
to
     q = SendMessage(Text1.hwnd, WM_GETTEXT, 254, ByVal s$)

If you do not pass it "ByVal", your app will crash when you make this call.  

:-)
--Nathan
0

Featured Post

Free Tool: Postgres Monitoring System

A PHP and Perl based system to collect and display usage statistics from PostgreSQL databases.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Background What I'm presenting in this article is the result of 2 conditions in my work area: We have a SQL Server production environment but no development or test environment; andWe have an MS Access front end using tables in SQL Server but we a…
If you need to start windows update installation remotely or as a scheduled task you will find this very helpful.
Show developers how to use a criteria form to limit the data that appears on an Access report. It is a common requirement that users can specify the criteria for a report at runtime. The easiest way to accomplish this is using a criteria form that a…
This lesson covers basic error handling code in Microsoft Excel using VBA. This is the first lesson in a 3-part series that uses code to loop through an Excel spreadsheet in VBA and then fix errors, taking advantage of error handling code. This l…

740 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question