How do I capture "Enter" Key in an Edit Control? - C / C++ / MFC Discussion Boards

skinnyreptile1686-Dec-05 13:00

6-Dec-05 13:00

Either of your methods is better than FindWindow(). Using memory mapped file looks clean but I am not too familiar with it. RegisterWindowMessage() seems easy enough for me to pick up quick.
Thanks a million, guys!

Re: FindWindow question

Blake Miller6-Dec-05 15:56

Blake Miller

6-Dec-05 15:56

Bzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzt....

foreach hWnd in TopLevelWindows {    <br />
  if(YOUR_MAGIC_COOKIE == SendMessage(hWnd, nMessage, 0, 0)) {

This will hang your application if the top-level window you sent a message to is not responding.

Better use the other technique, or else at LEAST use SendMessageTimeout.

Re: FindWindow question

Jörgen Sigvardsson7-Dec-05 7:06

Jörgen Sigvardsson

7-Dec-05 7:06

You're right!

--
Pictures[^] from my Japan trip.

Re: FindWindow question

Jörgen Sigvardsson7-Dec-05 7:09

Jörgen Sigvardsson

7-Dec-05 7:09

Another solution is to use HWND_BROADCAST and register another response message. Then collect the result in a/the message loop.

--
Pictures[^] from my Japan trip.

Re: FindWindow question

ThatsAlok6-Dec-05 19:05

ThatsAlok

6-Dec-05 19:05

vitowong wrote:
Either of your methods is better than FindWindow(). Using memory mapped file looks clean but I am not too familiar with it.

Have a look at this thread before using FindWindow api!-
PROS AND CONS of FINDWINDOW[^]

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV

CImageList question ...

Maximilien6-Dec-05 10:32

Maximilien

6-Dec-05 10:32

( must be a dumb day for me ... )

I have a CImageList that I use in a Tree Control; the bitmap contains non-mask images all bundled in one big bitmap; I create the imagelist like :

/// il is a class member.
il.Create( IDB_TREE_IMAGES, 16, 0, RGB(0,128,128) );  // the RGB is the color that I mark as tranparent in the bitmap.
il.SetBkColor( GetSysColor(COLOR_WINDOW) );
//...
SetImageList( &il, TVSIL_NORMAL ); // for the tree control.

This works well, all images are drawn transparently.

I want to split the big bitmap into individual smaller bitmaps, why ? because it's easier to add and remove images from the image list by adding and removing individual images instead of having to remove and resize the big image.

so, I do this :

m_ImageList.Create( 16, 14,ILC_COLOR4,30, 10 );//  RGB(0,128,128) );
CBitmap bm;
bm.LoadBitmap(ITB_TREE_COORDINATE);
COORDINATE_IMAGE_INDEX = m_ImageList.Add( &bm, RGB(0,128,128) );
bm.DeleteObject();
...
/// I do an Add for each individual bitmap.
m_ImageList.SetBkColor( GetSysColor(COLOR_WINDOW) );
//...
SetImageList( &m_ImageList, TVSIL_NORMAL );

but in this second case, the images are not drawn transparently; the bitmaps are 256 colors palettized bitmaps.

Any ideas ?

in my example that works, there is not specification for the type of images ( ILC_COLOR, ... ) and for my second example, I need to specify one, is there a default type I can/should use ?

Thanks.

Max.

Maximilien Lincourt
Your Head A Splode - Strong Bad

Re: CImageList question ...

Jörgen Sigvardsson6-Dec-05 10:47

Jörgen Sigvardsson

6-Dec-05 10:47

You're supposed to use ILC_MASK in the Create() call together with your color format (e.g. ILC_COLOR8).

--

How do I capture "Enter" Key in an Edit Control?

Jethro636-Dec-05 7:57

Jethro63

6-Dec-05 7:57

Hi:

I am trying to do what I thought would be a simple thing. I have a dialog which contains a variety of controls. One of my controls is an edit box. When a user is entering data through this control, I would like the user to be able to press the "ENTER" key to accept what has been entered.

I understand that dialogs will execute their DEFAULT button when "ENTER" is pressed but I THOUGHT that if I derived a new CMyEdit from CEdit and found the right function to override, I would be able to intercept the "ENTER" key and have it process the input instead. I must find a way to do this because I have users that feel that pressing enter after making an entry into a control like this is a natural thing to do and it is natural to expect that the input should be processed at that point. Frankly, I somewhat agree...

Is it my imagination or is this impossible? I have overridden every CEdit virtual function that I can find and NONE of them are called when I press "ENTER". Some of them are called if I press other keys, but not "ENTER".

What gives? What am I doing wrong?

Thanks in advance for your help!
Mark

-- modified at 14:33 Tuesday 6th December, 2005

Re: How do I capture &amp;amp;lt;RETURN&amp;amp;gt; in an Edit Control?

David Crow6-Dec-05 8:18

David Crow

6-Dec-05 8:18

Use the ES_WANTRETURN style.

"Take only what you need and leave the land as you found it." - Native American Proverb

Re: How do I capture "Enter" key in an Edit Control?

Jethro636-Dec-05 8:33

Jethro63

6-Dec-05 8:33

Hi David. Thanks for your response.

I did try this already. It made no difference. As it turns out, the VS help item that discusses "Want Return" says:

"This style has no effect on a single-line edit-box control."

I am using a single line edit box so I guess that explains it. I really don't want to use a multiline box so I am still stuck with this problem.

Thanks,
Mark

Re: How do I capture &quot;Enter&quot; key in an Edit Control?

David Crow6-Dec-05 8:38

David Crow

6-Dec-05 8:38

In the context of a single-line edit control, the enter key makes no sense. It should do the default behavior, which is to dismiss the dialog.

"Take only what you need and leave the land as you found it." - Native American Proverb

Re: How do I capture ENTER key in an Edit Control?

Jethro636-Dec-05 8:47

Jethro63

6-Dec-05 8:47

Well, I guess there is an "old school" that feels that pressing ENTER means "Take this input and process it". Some feel that it should then move the focus to the next item in the TAB order. It makes some sense to me although I would like nothing more at this point then to tell my users that this is the "new school" and "get over it". Unfortunately, I don't think they are going to drop this issue. I wish I could find a way...

Thanks again,
Mark

Re: How do I capture ENTER key in an Edit Control?

Nish Nishant6-Dec-05 9:02

Nish Nishant

6-Dec-05 9:02

Looks like you'll have to handle it in the dialog that contains the edit control. PreTranslateMessage is probably a good place to do this. Check for WM_KEYDOWN, use GetFocus to see if focus is on your edit control, check for VK_RETURN and do your stuff.

Re: How do I capture ENTER key in an Edit Control?

Jethro636-Dec-05 9:06

Jethro63

6-Dec-05 9:06

Hi Nishant:

I'll give that a try.

Thanks for your suggestion.
Mark

Re: How do I capture ENTER key in an Edit Control?

Jörgen Sigvardsson6-Dec-05 13:07

Jörgen Sigvardsson

6-Dec-05 13:07

I'm thinking you could probably trap the WM_KEYDOWN/VK_RETURN in your PreTranslateMessage function, and then fake a WM_KEYDOWN/VK_TAB. You should do the same for WM_KEYUP. That way you can reuse the tab code for the dialog.

However, I really wish you would reconsider doing this. This will annoy the hell out of some people, me included (well, in principle.. I don't know if I'm a user of your apps! Big Grin | :-D

). I'm using an app at work which uses enter as a means of navigating to the next field, while tab doesn't do it at all. This goes against everything I expect out of a Windows program, and makes me make a lot of mistakes. Mistakes that costs time, and makes me less productive. It's f**king with people's minds! Smile | :)

--
Pictures[^] from my Japan trip.

Force window on top

Shay Harel6-Dec-05 6:34

Shay Harel

6-Dec-05 6:34

Hi,

I wrote an application that has to warn a user of a certain state.
I want to make sure the user sees my window.
How do a I force it to be always on top of all other applications running ?
This window is a simple CDialog derived window.

Thanks in advance,
Shay

Re: Force window on top

David Crow6-Dec-05 7:01

David Crow

6-Dec-05 7:01

Does SetWindowPos() or BringWindowToTop() work for you?

"Take only what you need and leave the land as you found it." - Native American Proverb

Re: Force window on top

Shay Harel6-Dec-05 7:57

Shay Harel

6-Dec-05 7:57

Almost there....

I want to force it on top of all windows and SetWindowPost seems to do the best work. However, I need a way to get the exact size of the bottom right corner.

This code is crashing for me:

<br />
LPRECT lpRect;<br />
this->GetWindowRect(lpRect);<br />
this->SetWindowPos(&CWnd::wndTopMost,10,10,lpRect->right,lpRect->bottom,SWP_SHOWWINDOW);<br />

Re: Force window on top

David Crow6-Dec-05 8:17

David Crow

6-Dec-05 8:17

Shay Harel wrote:
LPRECT lpRect;

Change to:

RECT Rect;

"Take only what you need and leave the land as you found it." - Native American Proverb

Re: Force window on top

Shay Harel6-Dec-05 8:32

Shay Harel

6-Dec-05 8:32

this one worked, thanks !

Re: Force window on top

Blake Miller6-Dec-05 9:43

Blake Miller

6-Dec-05 9:43

Also, you could be seriously jacking up your window position, if it is already positioned near the upper left corner with only a little bit of the lower right corner showing.
I strongly recommend something like:

this->SetWindowPos(
&CWnd::wndTopMost,10,10,
Rect.right - Rect.left, // its width
Rect.bottom - Rect.Top, // its height
SWP_SHOWWINDOW);

Or even

this->SetWindowPos(
&CWnd::wndTopMost,10,10,
max(Rect.right - Rect.left, 100), // its width
max(Rect.bottom - Rect.Top, 100), // its height
SWP_SHOWWINDOW);

If you are REALLY paranoid, like me OMG | :OMG:

IsBadReadPtr vs IsBadStringPtr

Chintoo7236-Dec-05 6:11

Chintoo723

6-Dec-05 6:11

What is the difference between IsBadReadPtr and IsBadStringPtr?

thanks!

Re: IsBadReadPtr vs IsBadStringPtr

David Crow6-Dec-05 7:03

David Crow

6-Dec-05 7:03

One specifies a nul-terminated string, the other does not.

"Take only what you need and leave the land as you found it." - Native American Proverb

Re: IsBadReadPtr vs IsBadStringPtr

Jörgen Sigvardsson6-Dec-05 12:59

Jörgen Sigvardsson

6-Dec-05 12:59

Be cautious when you use these functions. Especially so the IsBadWritePtr, as it works by "trying" to write to the provided memory area inside a structured exception handling block. If it fails with an exception, it makes the function return false. If it succeeds, it writes back the contents which was in the buffer before the write. Clearly, this introduces race conditions in a multithreaded environment.

There are also other sinister possible side effects. Unfortunately I can't remember what those were, but if my memory serves me right, Raymond Chen[^] has an article about it somewhere.

--
Pictures[^] from my Japan trip.

MS Access locking Problem

zinc_z6-Dec-05 5:05

zinc_z

6-Dec-05 5:05

Hi ,

I have VC++ application which listens on socket and get msgs, most of time one msg per second and I use MS Access to store my messages. Then I distribute these messages in different MS Access tables . My problem is I am getting error like record is blocked by Admin , can't access that record .

Now I want to know that how MS Access locking system works ? like If one thread is reading from Table 'A' so can other thread write to that table ?

And my senior collegue told me that he tried MS SQL server earlier to store these msgs but it did't work as it jammed the SQL Server.

Regards,
ZINC

ZINC

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.