Solved

Window handle

Posted on 1998-03-27
9
287 Views
Last Modified: 2008-02-01
How do you retrieve the handle of the main window in an SDI application?  I need the HWND value for various procedures, but not sure if I have it correctly.  Example prefered.

Thanks
0
Comment
Question by:jerm
  • 4
  • 4
9 Comments
 
LVL 4

Expert Comment

by:jtwine100697
Comment Utility
  Assuming you are using MFC, try AfxGetMainWnd().  That will return a CWnd*, from which you can obtain the HWND.

-=- James.
0
 

Accepted Solution

by:
HoJu earned 10 total points
Comment Utility
It's all going to depend on where you're trying to get the handle from ...

If you're getting it from within your main callback -- probably called WndProc -- then it should be your hwnd parameter.

If you're getting it from within other callbacks that have the main window as a parent window or an owner window, you can use:

hwndMain = (HWND) GetWindowLong(hwnd, GWL_HWNDPARENT);
or
hwndMain = (HWND) GetWindow(hwnd, GWL_OWNER);

... where hwnd is the handle of the window whose callback you're inside of.

Any other functions can be passed hwnd as a parameter, or you can simply have hwnd be a static HWND when you declare it in the first place, so you can access it from anywhere.

Hope that answers your question.
0
 
LVL 1

Expert Comment

by:vsinha
Comment Utility
I think a simpler solution would be:

hwndMain = (HWND) GetWindow(hwnd, GWL_OWNER);

I am however not an expert (currently) in this topic, so try it and correct me if I am wrong.
0
 
LVL 1

Expert Comment

by:vsinha
Comment Utility
sorry about the previous comment, it should have been:

I think a simpler solution would be:

hwndMain = GetParent(hwnd);

I am however not an expert (currently) in this topic, so try it and correct me if I am wrong.
0
How your wiki can always stay up-to-date

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

 
LVL 4

Expert Comment

by:jtwine100697
Comment Utility
  "vsinha", you are assuming that the immediate parent will be the main window...

   That is not always the case. :P

-=- James.
0
 
LVL 1

Expert Comment

by:vsinha
Comment Utility
Jtwine, I guess this is not my question, but it would be very helpful if you could give me an example where my soln. won't work and yours will. Also could you explain why?

0
 
LVL 4

Expert Comment

by:jtwine100697
Comment Utility
  If you are in, say, a dialog box, or in a custom control that is implemented in a window (or in the view of an MFC Doc/View MDI application), the parent of the "current" window might not be the "main window" of the application.  (Note the question reads "various procedures".  That could mean various windows.)

   You (We) need more details on the specifics of where "jerm" wants to obtain the main window from.  If using MFC, AfxGetMainWnd() works...  Anywhere.

-=- James.

0
 
LVL 1

Expert Comment

by:vsinha
Comment Utility
jtwine, thanks. If you are not using MFC would this function work:

HWND GetMainWnd(HWND hwnd)
{
   while (GetParent(hwnd) != NULL)
      hwnd = GetParent(hwnd);
   
   return hwnd;
}

[written, based on the fact that the parent of the main window is NULL]

Also didn't HoJu`s soln. have the same drawback as mine.
0
 
LVL 4

Expert Comment

by:jtwine100697
Comment Utility
  Yes, the function (loop) will work as expected.  (That, BTW, is similar to how MFC delegates control [updates] for Context Menus!)

   And yes, the Answer posted by "Hoju" has the same problem.  That is why I try to contain myself and post suggestions before wasting time with possibly incorrect answers! :)

-=- James.
0

Featured Post

How to run any project with ease

Manage projects of all sizes how you want. Great for personal to-do lists, project milestones, team priorities and launch plans.
- Combine task lists, docs, spreadsheets, and chat in one
- View and edit from mobile/offline
- Cut down on emails

Join & Write a Comment

  Included as part of the C++ Standard Template Library (STL) is a collection of generic containers. Each of these containers serves a different purpose and has different pros and cons. It is often difficult to decide which container to use and …
Container Orchestration platforms empower organizations to scale their apps at an exceptional rate. This is the reason numerous innovation-driven companies are moving apps to an appropriated datacenter wide platform that empowers them to scale at a …
The goal of the tutorial is to teach the user how to use functions in C++. The video will cover how to define functions, how to call functions and how to create functions prototypes. Microsoft Visual C++ 2010 Express will be used as a text editor an…
The goal of the video will be to teach the user the concept of local variables and scope. An example of a locally defined variable will be given as well as an explanation of what scope is in C++. The local variable and concept of scope will be relat…

763 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

Need Help in Real-Time?

Connect with top rated Experts

12 Experts available now in Live!

Get 1:1 Help Now