C / C++ / MFC

Re: SendMessage with WM_SETFOCUS and SetFocus() function

5-Dec-11 23:50

The WM_SETFOCUS message is sent to a window by the Windows system, as the result of a call to SetFocus() or the user setting the focus to the window by mouse or keyboard. Thus option 2 is the correct way to do it.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Albert Holguin6-Dec-11 3:34

Albert Holguin

6-Dec-11 3:34

Just look at the description of SetFocus():
http://msdn.microsoft.com/en-us/library/windows/desktop/ms646312%28v=vs.85%29.aspx[^]

By reading that, you'll see that SetFocus() does a number of calls to make sure the focus is set correctly (kills the previous focus, activates the parent window of the control).

why pApplication.CreateInstance( _T("Excel.Application") ) FAILED?

Le@rner5-Dec-11 19:45

Le@rner

5-Dec-11 19:45

i am reading excel file .

Excel::_ApplicationPtr pApplication;

pApplication.CreateInstance( _T("Excel.Application") );

but i dont understand why pApplication.CreateInstance( _T("Excel.Application") ) failed on my PC while its working fine on another PC.

please help me for this.

thanks.

Re: why pApplication.CreateInstance( _T("Excel.Application") ) FAILED?

CPallini5-Dec-11 21:47

Re: why pApplication.CreateInstance( _T("Excel.Application") ) FAILED?

5-Dec-11 21:47

Le@rner wrote:
but i dont understand why pApplication.CreateInstance( _T("Excel.Application") ) failed

Because you didn't bother to check the return value.

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Le@rner5-Dec-11 22:17

Le@rner

5-Dec-11 22:17

no chk this

if ( FAILED( pApplication.CreateInstance( _T("Excel.Application") ) ) )
			{
				AfxMessage( _T("Failed to initialize Excel!") );
				
				return ;
			}

Re: why pApplication.CreateInstance( _T("Excel.Application") ) FAILED?

Richard MacCutchan5-Dec-11 22:35

Re: why pApplication.CreateInstance( _T("Excel.Application") ) FAILED?

5-Dec-11 22:35

It is no use printing a message such as the above when something fails, as it provides no useful information. ~~You need to capture the system error code from GetLastError() and print its details to find out why your program fails.~~ I am assuming that you have all the necessary libraries installed on your PC in the first place.

Oops: sorry you need to interpret your HRESULT as CPallini suggests.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

CPallini5-Dec-11 22:38

Re: why pApplication.CreateInstance( _T("Excel.Application") ) FAILED?

5-Dec-11 22:38

I believe that's the optimal way with standard API (like Win32). On the other hand, COM calls provides error code in return value.

Richard MacCutchan5-Dec-11 23:47

Re: why pApplication.CreateInstance( _T("Excel.Application") ) FAILED?

5-Dec-11 23:47

You are, of course, correct; it was my bad (mea culpa) and I have fixed it.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

CPallini5-Dec-11 22:36

Re: why pApplication.CreateInstance( _T("Excel.Application") ) FAILED?

5-Dec-11 22:36

That way, you are discarding a precious info, the HRESULT return value.

C++

HRESULT hr;
hr = pApplication.CreateInstance( _T("Excel.Application");
if ( FAILED(hr))
{
  // show error message AND error code here
  return;
}

is far better.

Le@rner17-Jan-12 1:17

Le@rner

17-Jan-12 1:17

C++

HRESULT hr;
  hr = pApplication.CreateInstance( _T("Excel.Application");
  if ( FAILED(hr))
  {
//format Message Of GetLastError();

   "An attempt was made to reference a token that does not exist" error comes when i format the message of GetLastError().    
return;
  }

modified 17-Jan-12 7:33am.

Re: why pApplication.CreateInstance( _T("Excel.Application") ) FAILED?

CPallini17-Jan-12 1:36

Re: why pApplication.CreateInstance( _T("Excel.Application") ) FAILED?

17-Jan-12 1:36

I don't know about, however it looks like Excel doesn't allow your application to access it (I guessed that from this page[^]: they face the same error message, see the "Configure Excel application to be accessed by non-System account" section. You may try to run your application 'As Administrator' to validate such hypothesys.

Sampath57927-Aug-19 1:15

Sampath579

27-Aug-19 1:15

Hi.

I am facing exactly same problem and posted in the query in below link.

https://www.codeproject.com/Answers/5165616/Excel-applicationptr-createinstance-is-failing#answer1

Can any one explain how to resolve this CreateInstance() failure.

Windows 10 - 64 bit and Office 365 64bit and VS2017 enterprise edition i am using.

win32 edit box, validating text

jkirkerx5-Dec-11 9:20

jkirkerx

5-Dec-11 9:20

This is my first textbox using CreateWindow "edit", and I want to make sure the box is not empty.

So I sent the message, and the buffer comes back 0x0000, for the first wchar.

Is there a common method that folks use in c++ to check the contents of the box before performing any actions?

I wrote this, simple, but not good enough

// Get the Database Name
LRESULT iTextSize = SendMessage(txt_SQL_DatabaseCreate_DB_Field, EM_GETLIMITTEXT, 0, 0);
WCHAR *szDatabaseName = new WCHAR[iTextSize];
			SendMessage(txt_SQL_DatabaseCreate_DB_Field, WM_GETTEXT, iTextSize, (LPARAM)szDatabaseName);

if ((szDatabaseName[0] != 0x0000) && wcslen(szDatabaseName) >0)) {

David Crow5-Dec-11 10:52

David Crow

5-Dec-11 10:52

jkirkerx wrote:
LRESULT iTextSize = SendMessage(txt_SQL_DatabaseCreate_DB_Field, EM_GETLIMITTEXT, 0, 0);

You should probably be using WM_GETTEXTLENGTH instead.

"One man's wage rise is another man's price increase." - Harold Wilson

"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

"Show me a community that obeys the Ten Commandments and I'll show you a less crowded prison system." - Anonymous

jkirkerx6-Dec-11 6:46

jkirkerx

6-Dec-11 6:46

That was a good idea, I changed my code to that, it was more accurate.

enhzflep5-Dec-11 17:21

enhzflep

5-Dec-11 17:21

I just use the GetWindowTextLength and GetWindowText functions, something like this:

C++

case IDC_BTN_TEST:
    editWnd = GetDlgItem(hwndDlg, IDC_EDIT1);
    stringLength = GetWindowTextLength(editWnd);
    if (stringLength != 0)
    {
        strBuffer = new WCHAR[stringLength+2];
        GetWindowText(editWnd, strBuffer, stringLength+1);
        MessageBox(hwndDlg, strBuffer, L"title", MB_OK);
        delete strBuffer;
    }
    return TRUE;

For some reason, calling GetWindowText with stringLength (as opposed to stringLength+1) returns the string minus the last character... WTF | :WTF:

Randor 5-Dec-11 17:37

Randor

5-Dec-11 17:37

enhzflep wrote:
For some reason, calling GetWindowText with stringLength (as opposed to stringLength+1) returns the string minus the last character...

That is of course because 'C' strings are terminated with a NULL character. The GetWindowTextLength function sends the WM_GETTEXTLENGTH message[^] and therefore is returning only the length of the text excluding the NULL character. When allocating space for C-style strings you should always calculate the bytes required as:

((number of characters) * sizeof(TCHAR)) + sizeof(TCHAR)

Feel free to replace TCHAR with char or wchar_t dependent on your compiler/platform and ANSI/Unicode build.

Best Wishes,
-David Delaune

Pyramid of Asterisk - Reverse?

jkirkerx6-Dec-11 7:00

jkirkerx

6-Dec-11 7:00

I didn't know that existed, makes sense, SetWindowText, GetWindowTextLength. So that's a quick way to see if there is data without sending a message, or get the size +1 for allocating space.

I did get the regex to work for wchar's, so now I can validate the input as well.

Yolande MR5-Dec-11 8:34

Yolande MR

5-Dec-11 8:34

I'm building a pyramid of asterisk with for loop statement:

for (int i = 1, i < 5, i++)
{
for (int j = 1; j <= i, j++)
{
cout << "*";
}
cout << endl;
}

here's is the question: i need another for loop statement to reverse the pyramid. I need it has to do something with the spaces, but could not write one. Since i don't have a database to look at. Could someone hint me in the right direction?

Albert Holguin5-Dec-11 8:41

Albert Holguin

5-Dec-11 8:41

Not clear... what do you mean a for loop to reverse the pyramid? ..you mean you want to undo what you just did?

Richard MacCutchan5-Dec-11 8:43

5-Dec-11 8:43

"Normal" counts from 1 to 5, so I would guess that reverse counts down from 5 to 1.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Yolande MR5-Dec-11 8:47

Yolande MR

5-Dec-11 8:47

Richard M.:
reverse count down from 5 to 1 only inverted the pyramid, not REVERSE it !
what I'm trying to create is a RIGHT-ALIGNED pyramid going from 1 to 5 in counts, as oppose to a left-aligned pyramid counting from 1 to 5. Hope you get this.