C / C++ / MFC Discussion Boards

Rajveer22-Feb-02 7:37

22-Feb-02 7:37

I've created an MDI application. I've also created a dialog box for the app, and I've inserted an extra command in the file menu. How do I make that particular menu command open the dialog box I just created?

Re: opening a dialog box

Sonu Kapoor22-Feb-02 7:51

Sonu Kapoor

22-Feb-02 7:51

CMyDialog dlg;
dlg.DoModal();

Best Regards

Sonu

Re: opening a dialog box

Paul M Watt22-Feb-02 8:00

Paul M Watt

22-Feb-02 8:00

If you are using plain WIN32 programming, declare a DialogProc function similar to your main WindowProc like this:

<br />
INT_PTR CALLBACK DialogProc(<br />
  HWND hwndDlg,  // handle to dialog box<br />
  UINT uMsg,     // message<br />
  WPARAM wParam, // first message parameter<br />
  LPARAM lParam  // second message parameter<br />
);<br />

This function will handle all of the button click events and initialization messages similar to your window proc function.

This function returns an int rather than an LRESULT, because messages in a dialog handler need to return TRUE or FALSE whether they are handled or not.

Next you need to decide whether you want to have a modal or a modeless dialog appear.

A Modal dialog is one that demands all of the users input attention. The user can not switch to any other window in your program until they close this window. If you want this type of window, then call DialogBox. In your DialogProc function for a modal dialog box, you will want to call EndDialog to close the dialog.

A Modeless dialog is one that will allow the user to switch to other windows in your application, and can still remain open. This style is good for toolboxes and things like that. You will want to use CreateDialog to create this type of window. You will want to store thet window handle that is returned to you, and then call ShowWindow when you are ready to display the dialog.
You can close a modeless dialog the same way you would any other window with DestroyWindow.

If you are using MFC or WTL there are other methods. If you have more questions just let me know.

Re: opening a dialog box

Tili2-Dec-02 22:03

Tili

2-Dec-02 22:03

Hi.
I have a question about DialogProc.
I am creating a dialog based application without any other parent window. I am also changing the color of background and all that but still after sometime the window behaves awkwardly and shows 5 and 6 instead of arrows for an editbox. The colours go away and some area is white and rest is blue and the whole thing messes up.
I ma not handling WM_PAINT and I want it to draw itself. The caption bar goes away too.
a complete information is here. But remember there is not parent window and Dialog is itself parent.

http://www.codeproject.com/script/comments/forums.asp?forumid=1647&select=353503&df=6&kw=DialogProc#xx353503xx

Please have a look at it. If you have any such application tht is dialog based like MFC then please show me how to do it right. Why doesnt it draw caption bar itself.
Thanks

In my dream, I was dorwning my §orrow§
But my §orrow§, they learned to §wim

Re: opening a dialog box

Jon Hulatt22-Feb-02 8:06

Jon Hulatt

22-Feb-02 8:06

in the code for the command handler:

CWhateverYourDlgClassIs dlg;
dlg.DoModal();

it's that easy!

Sorry to dissapoint you all with my lack of a witty or poignant signature.

Re: opening a dialog box

mr200322-Feb-02 11:48

mr2003

22-Feb-02 11:48

yo,, this is Ehsan,,
wassup...

Ehsan Behboudi

Thread Problems

Jon Hulatt22-Feb-02 7:37

Jon Hulatt

22-Feb-02 7:37

Hi,

Need more help.

I have a single instance of a CAsyncSocket derived class, which is acting as a listening daemon.

When i accept a new connection, I create a new instance of a new object, which is again a CAsyncSocket derived class. This new object is tuned to handle the SMTP conversation itself.

// create a new connection object for the mail
	CMailConnection *p_MailConn = new CMailConnection;

	SOCKADDR_IN pSockAddr;
	int nSockAddrLen=sizeof(pSockAddr);
	
	if (Accept((*p_MailConn),(sockaddr *) &pSockAddr,&nSockAddrLen) == 0)

Now I want to enforce a limit on the number of concurrent connections. I can see two ways of doing this... One is messy and involves manually keeping a count of connections. The other, better way (IMHO) is to use semaphores. This way I can make my OnAccept thread wait for a free connection using the semaphore on WaitForSingleObject().

However, for this to work, I need to get each instance of my CMailConnection object running in it's own thread. I've used worker threads before, ie. calling a function within AfxBeginThread() to do some heavy processing. But I don't know how to start a thread in this case. Can't see that I can use the regular worker threads model: MSDN says that the thread is killed when the pfnThreadProc returns.

Evidently, there is some internal MFC trickery inside of CAsyncSocket that handles the event functions like OnReceive() etc. Dunno where this code is or if it's relevant.

Help!

Sorry to dissapoint you all with my lack of a witty or poignant signature.

Re: Thread Problems

Paul M Watt23-Feb-02 16:10

Paul M Watt

23-Feb-02 16:10

Since you are using a Derived class from CAsyncSocket, you could simply add a static member variable to the derived class.

Then you would expose a static member function of the class that will create a new instance of the class only if the static count is less than the limit that you want to impose. When ever the objects are destroyed, they will decrement the count of current objects.

Then you can hide the constructors by declaring them private, this will make it so that the only way that users of your class can create a new object by calling your static member function.

The thread solution that you were talking about should be able to work, you would need to structure your worker thread procedure to start, create your new object, attempt to create the connection, then loop while it is working. It would only terminate with some message or event that you set for the thread. With out really knowing the details of what this thread needs to perform, I cannot give any more hints for this solution.

Re: Thread Problems

Jon Hulatt24-Feb-02 21:56

Jon Hulatt

24-Feb-02 21:56

Thanks for those pointers.

Would a "User interface thread" be a help? the UI thread appears to enter is own message loop and runs until explicitly told to stop.

Jon

Sorry to dissapoint you all with my lack of a witty or poignant signature.

Loading bitmaps

22-Feb-02 6:49

Hi all

I need some help. I am making an mp3 player and i designed an emblem for the media player but i dont know how to insert the image into MFC. Can someone please lend me a hand and tell me how i can load the image from my harddrive to a "Picture" control in the dialog Box.
Thanks Laugh | :laugh:

Re: Loading bitmaps

Not Active22-Feb-02 7:11

Not Active

22-Feb-02 7:11

Start at CStatic::SetBitmap, you should be able to figure it out from there.

Re: Loading bitmaps

Paul M Watt22-Feb-02 7:15

Paul M Watt

22-Feb-02 7:15

You can either insert your bitmap into your resource file, associate the bitmap with the picture control at design time and the dialog will load the image for you.

Or you can Load the bitmap with LoadImage (LoadBitmap calls loadImage), then you can use the HBITMAP handle that you receive from LoadImage and send a STM_SETIMAGE message.

<br />
SendMessage( <br />
  (HWND) hWnd,              // handle to destination window <br />
  STM_SETIMAGE,             // message to send<br />
  (WPARAM) wParam,          // image type<br />
  (LPARAM) lParam          // handle to image (HANDLE)<br />
);<br />

Parameters
wParam
Specifies the type of image to associate with the static control. This parameter can be one of the following values:
IMAGE_BITMAP
IMAGE_CURSOR
IMAGE_ENHMETAFILE
IMAGE_ICON

Teh MFC equivalent is probably CStatic::SetImage

Broadcasting the command

yellowine22-Feb-02 6:23

yellowine

22-Feb-02 6:23

I have an MFC app with one CMainFrame, one doc, and multiple views, each view is associated with the same doc but different child frames (CMDIChildFrame).Each view handle certain set of manu commands.

If I have updated the doc's data thru one of the views, how do I broadcast the command so that other views can respond the command?

Re: Broadcasting the command

Tim Smith22-Feb-02 6:30

Tim Smith

22-Feb-02 6:30

You can invoke the UpdateAllViews method of CDocument.

Tim Smith

I know what you're thinking punk, you're thinking did he spell check this document? Well, to tell you the truth I kinda forgot myself in all this excitement. But being this here's CodeProject, the most powerful forums in the world and would blow your head clean off, you've got to ask yourself one question, Do I feel lucky? Well do ya punk?

Re: Broadcasting the command: Problem with UpdateAllViews()

yellowine22-Feb-02 6:34

yellowine

22-Feb-02 6:34

Yes, UpdateAllViews() informs all other views to update their contents. What about if I want other views to respond in a way like following:

if ID_COMMAND1 is send by pView1

then I want:

pView2->WelcomeYou();
pView3->MakeDinnerForYou();
...
pViewn->GoFishing()..

Any idea?

Re: Broadcasting the command: Problem with UpdateAllViews()

Tim Smith22-Feb-02 6:46

Tim Smith

22-Feb-02 6:46

Other than using the hint parameters, no, I don't have any ideas. Not totally sure what you want.

If X happens in view 1, then you want view 2 to do Y, view 3 to do Z, etc, then the hint parameters should work.

Tim Smith

I know what you're thinking punk, you're thinking did he spell check this document? Well, to tell you the truth I kinda forgot myself in all this excitement. But being this here's CodeProject, the most powerful forums in the world and would blow your head clean off, you've got to ask yourself one question, Do I feel lucky? Well do ya punk?

Re: Broadcasting the command: Problem with UpdateAllViews()

Nish Nishant22-Feb-02 9:18

Nish Nishant

22-Feb-02 9:18

yellowine wrote:

if ID_COMMAND1 is send by pView1

then I want:

pView2->WelcomeYou();
pView3->MakeDinnerForYou();
...
pViewn->GoFishing()..

I think you might maintain a global stack of messages and handle them individually in the individual views iterating through each message in the stack. Push only those msgs into the stack that you wish to have handlers for in the different views.

My most recent CP article :-

A newbie's elementary guide to spawning processes

www.busterboy.org

Re: Broadcasting the command: Problem with UpdateAllViews()

yellowine22-Feb-02 10:35

yellowine

22-Feb-02 10:35

Good idea. Thanks.

Re: Broadcasting the command: Problem with UpdateAllViews()

pba_22-Feb-02 10:40

pba_

22-Feb-02 10:40

Something like this ?

CMyMainWnd::OnCommand1()
{
CMyDoc* pDoc = GetActiveDocument();

POSITION pos = pDoc->GetFirstViewPosition();
while( pos )
{
pView = pDoc->GetNextView( &pos);
if( pView->IsKindOf(RUNTIME_CLASS(CMyView1)))
{
((CMyView1*)pView)->WelcomeYou();
}
....etc
}
}

Re: Broadcasting the command: Problem with UpdateAllViews()

yellowine22-Feb-02 10:42

yellowine

22-Feb-02 10:42

Thanks for your idea. I do think this approach works except a maintainence problem. Any time I add a view or I have a new command which will cause a train reaction for other view, I have to add a new handler in the CMyMainFrame or add a new IsKindOf(..) in the while loop, right?

Re: Broadcasting the command: Problem with UpdateAllViews()

pba_22-Feb-02 12:04

pba_

22-Feb-02 12:04

Or you can send the message to each view ...
//
while(....)
{
pView->SendMessage( );
}

and each view will process the message in his own way.

Re: Broadcasting the command

22-Feb-02 7:00

Think about overriding OnCmdMsg( )and route the messages yourself.

Re: Broadcasting the command

yellowine22-Feb-02 10:36

yellowine

22-Feb-02 10:36

I will take this approach and give it a try.

Thanks.

Deallocating Tree Control Data

Aaron Schaefer22-Feb-02 6:17

Aaron Schaefer

22-Feb-02 6:17

Hi There,

I have a question about tree controls. If I set a tree item's data to something like a pointer to a class or something, when is the appropriate time to delete the pointer?

This is inside a dialog bar which houses the tree control.

Thanks,

Aaron

Re: Deallocating Tree Control Data

Tim Smith22-Feb-02 6:19

Tim Smith

22-Feb-02 6:19

When you receive a TVN_DELETEITEM notification for an element in the tree control. That is by far the best way.

Tim Smith

I know what you're thinking punk, you're thinking did he spell check this document? Well, to tell you the truth I kinda forgot myself in all this excitement. But being this here's CodeProject, the most powerful forums in the world and would blow your head clean off, you've got to ask yourself one question, Do I feel lucky? Well do ya punk?

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