Capture text from another non-Delphi application window (Views: 2146)
Problem/Question/Abstract: I need to capture the text from a scrolling text window in another program that I don't have access to only through a window handle. Can I use SendMEssage or something to ge the text with WM_GETTEXT type message. I know there are programs like spell checkers that can do this. Any help would be appreciated. Answer: Solve 1: The example runs 'chkdsk.exe c:\' and displays the output to Memo1. Put a TMemo (Memo1) and a TButton (Button1) on your form. Put this code in the OnCLick of Button1: procedure TForm1.Button1Click(Sender: TObject); procedure RunDosInMemo(DosApp: string; AMemo: TMemo); const ReadBuffer = 2400; var Security: TSecurityAttributes; ReadPipe, WritePipe: THandle; start: TStartUpInfo; ProcessInfo: TProcessInformation; Buffer: Pchar; BytesRead: DWord; Apprunning: DWord; begin with Security do begin nlength := SizeOf(TSecurityAttributes); binherithandle := true; lpsecuritydescriptor := nil; end; if Createpipe(ReadPipe, WritePipe, @Security, 0) then begin Buffer := AllocMem(ReadBuffer + 1); FillChar(Start, Sizeof(Start), #0); start.cb := SizeOf(start); start.hStdOutput := WritePipe; start.hStdInput := ReadPipe; start.dwFlags := STARTF_USESTDHANDLES + STARTF_USESHOWWINDOW; start.wShowWindow := SW_HIDE; if CreateProcess(nil, PChar(DosApp), @Security, @Security, true, NORMAL_PRIORITY_CLASS, nil, nil, start, ProcessInfo) then begin repeat Apprunning := WaitForSingleObject(ProcessInfo.hProcess, 100); Application.ProcessMessages; until (Apprunning <> WAIT_TIMEOUT); repeat BytesRead := 0; ReadFile(ReadPipe, Buffer[0], ReadBuffer, BytesRead, nil); Buffer[BytesRead] := #0; OemToAnsi(Buffer, Buffer); AMemo.Text := AMemo.text + string(Buffer); until (BytesRead < ReadBuffer); end; FreeMem(Buffer); CloseHandle(ProcessInfo.hProcess); CloseHandle(ProcessInfo.hThread); CloseHandle(ReadPipe); CloseHandle(WritePipe); end; end; begin {Button1 code} RunDosInMemo('chkdsk.exe c:\', Memo1); end; Unfortunaly that will only work with applications that send output to stdout. A Windows application usually doesn't do this. Solve 2: The usually use different techiques, like OCR on a screen bitmap. There is simply no generic method to get text from other windows. What you can try, however, is this: function GetTextFromWindow(wnd: HWND): string; var count: Cardinal; begin result := ''; if SendMessageTimeout(wnd, WM_GETTEXTLENGTH, 0, 0, SMTO_ABORTIFHUNG, 1000, count) <> 0 then begin if count = 0 then Exit; SetLength(result, count); if SendMessageTimeout(wnd, WM_GETTEXT, count + 1, lparam(@result[1]), SMTO_ABORTIFHUNG, 1000, count) = 0 then result := ''; end; end; procedure TForm1.Button1Click(Sender: TObject); var wnd: HWND; begin wnd := FindWindow('notepad', nil); if wnd <> 0 then begin wnd := GetWindow(wnd, GW_CHILD); if wnd <> 0 then memo1.text := GetTextfromwindow(wnd); end else memo1.text := 'Notepad not running.'; end; |