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Hi All,
VC++ 6, MFC, WinXP
My application's main interface consists of a FormView with a few controls – a tab control and a custom CView based control. In operation, the user *should* (yes, I know …not in the real world) click and then release the left mouse button in this view make a selection. The act of clicking starts a process and the act of releasing ends the process. Specifically, the application sends MIDI notes, similar to a piano keyboard control: MIDI note ON when the left mouse button is pressed, and MIDI note OFF when the button released. I need to send a MIDI note OFF message if the user drags out of the selection window - that would stop the note from playing when the mouse leaves the window. The idea is as long as the left mouse button is pressed, the note will play.
All works fine when the user clicks and releases in the same view but if they click, drag away, then release in a different view, the original view does not get notified and the selection remains - in other words, the note stays playing.
I’ve looked through the forums and articles and have tried a few of the suggestions but have yet not found any method to get notified immediately when the mouse leaves the active view if the left button is still down. Most of the methods have a "delayed action" before they notify the original view and only seem to trigger if the user clicks on another view - AFTER they released the left mouse initially on that non-original view. I need to find a way to get notified immediately should the mouse leave the active view when its left button is down.
Any suggestions and help would be appreciated.
Paul
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See CWnd::SetCapture[^], this redirects all mouse messages to the given window until you either call ReleaseCapture or the mouse capture is lost because of some other event (then you get WM_MOUSECAPTURED[^] to notify you about this, you get this also when calling SetCapture/ReleaseCapture explicitly), alternatively, see TrackMouseEvent[^], maybe that better suits your needs.
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Leela: Fry, you're wasting your life sitting in front of that TV. You need to get out and see the real world.
Fry: But this is HDTV. It's got better resolution than the real world <
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Works perfectly!
SetCapture() in the OnLButtonDown() handler and ReleaseCapture() in the OnLButtonUp() handler gives me better functionality. Now as long as the user lets go of the left mouse button anywhere, the view gets the mouse input and the OFF command is sent.
Thank you for the direction and the links (and lesson)!
Best Regards,
Paul
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Yourwelcome. Just be careful, as i said, you might lose the mouse capture because of some "external" event, like a dialog box popping up from another application, and if you don't handle this correctly the user might need to click the correct spot in your application to trigger a button-up. I suggest, in OnLButtonDown, use SetCapture to grab the mouse input and start your midi play, in OnLButtonUp, use ReleaseCapture and in OnCaptureChanged, if you are loosing the capture, stop the sound. This way, both if the user releases the key or some other event triggers the capture-change, you won't end up with your program playing the sound endlessly.
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Leela: Fry, you're wasting your life sitting in front of that TV. You need to get out and see the real world.
Fry: But this is HDTV. It's got better resolution than the real world <
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Oh, I have to admit I missed that suggestion before but it makes perfect sense. I've moved the code in OnLButtonUp()(keeping the ReleaseCapture() call) to OnCaptureChanged(). As is, it looks like it works in the same exact way as before but has the 'safety' features you stated. Thanks again!
Best Regards,
Paul
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Yourwelcome, again. 
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Leela: Fry, you're wasting your life sitting in front of that TV. You need to get out and see the real world.
Fry: But this is HDTV. It's got better resolution than the real world <
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hello guys...I declared an array in one file MyClass.cpp, use it and then using the extern keyword I access it in MyProjDlg.cpp like this..
MyClass.cpp
-----------
LPTSTR Array[];
Arrar[index] = StudentName;
MyProjDlg.cpp
-------------
extern LPTSTR Array[];
BOOL CMyProjDlg::OnInitDialog()
{
...........
...........
Listbox.AddString(Array[index]);
}
But it is showing 3 errors, I dont know why?
MyClass.obj : error LNK2001: unresolved external symbol "char * * Array"
MyProjDlg.obj : error LNK2001: unresolved external symbol "char * * Array"
Debug/MyProj.exe : fatal error LNK1120: 1 unresolved external symbol
thnx
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What you've done has many problems.
Instead you must do this -
You want to store many strings. So declare std::vector<std::string> Array;
To add to this array you do - Array.push_back(StudentName);
In the other file, declare it extern - extern std::vector<std::string> Array;
Now you can loop through this and use and index to access all elements as you've already done.
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As «_Superman_» said, you've got lots of problems here. Firstly note these lines:
LPTSTR Array[];
Arrar[index] = StudentName;
You haven't allocated any storage for the array! Ask youself how big it is! You really should use a std::vector[^] (as «_Superman_» suggested), especially since you don't seem to have a grasp of basic memory managment. Try something like this:
MyClass.h
-----------
#include <string>
#include <vector>
extern std::vector<std::string> Array;
MyClass.cpp
-----------
#include "MyClass.h"
std::vector<std::string> Array;
MyProjDlg.cpp
-------------
#include "MyClass.h"
BOOL CMyProjDlg::OnInitDialog()
{
Array.push_back("String 1");
Array.push_back("String 2");
Listbox.AddString(Array[index].c_str());
}
Steve
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thnx....this was really helpful...
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I am passing float value to a varibale, but I am not getting correct value
float Val1=4.6;
float Val2 = Val1;//getting 4.5999999
I am getting 4.5999999, How can I get the return value as 4.6?
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This is due to floating point precision. See here[^] (or google for it) for more information. If you really need more precision, you can always use a double (but I doubt that you need it).
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Welcome to floating point math! Your result is typical and is why the #1 rule on doing floating point math is to never depend on the value being exact. You will need to compensate or use a higher precision number type, depending on what you are trying to accomplish.
In most situations the difference in calculated values is not significant, but sometimes it is. The worst resolution problems usually occur when you subtract 2 numbers that are close, then do further manipulations. If you are checking the value with if statements, for example, then you need to check that the value is within a reasonable tolerance.
Search around using Google and Bing for "floating point precision" and you should find lots of information.
CQ de W5ALT
Walt Fair, Jr., P. E.
Comport Computing
Specializing in Technical Engineering Software
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Read here.
"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
"Man who follows car will be exhausted." - Confucius
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Wow! Fantastic article: even those who already know the topic should read (and learn) it!
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Hi, I am using HtmlHelp api to display help window in my
project.
HtmlHelp(hWnd, File Name, HH_HELP_CONTEXT, Id);
I have a Parent Dialog contains some controls. Whenever I press a
help button, help window should be opened.
After opening the help window, I am able to interact with the Parent Dialog.
But the problem is, the help windopw is still on the top of the parent dialog.
I want to push the help window behind Parent Dialog whenever I interact with
the Parent Dialog.
Please throw some ideas.
Regards
msr
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msr_codeproject wrote: But the problem is, the help windopw is still on the top of the parent dialog.
I want to push the help window behind Parent Dialog whenever I interact with
the Parent Dialog.
It sounds to me like you want to change the window Z-Order[^] and remove the HWND_TOPMOST flag. The SetWindowPos Function[^] can do that for you. Something like:
SetWindowPos(YourHelp->hWnd, HWND_NOTOPMOST, 0, 0 , 0 , 0, SWP_NOMOVE | SWP_NOSIZE);
Best Wishes,
-David Delaune
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I am developing a SDI application. When I change anything in .rc file, like add string in string table, add entry in accel table, I get error in compilation "error RC2135 : file not found: 0".
How can I resolve this issue?
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Are you editing the rc file manually ? You shouldn't do it.
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Well, unless you know what you're doing...
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]
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Yes, which doesn't seem to be the case for the OP, since he's getting that error 
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Post the .rc entries here to show what you have changed.
Just say 'NO' to evaluated arguments for diadic functions! Ash
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Hi all,
i m using CreateFile to access com port,
i want to use this port at same time by the diffrent thread.
currently in my application if i run 5 threads than only any one is able to read this other return the error of Invalid Handle or Paramete is incorrect.
please help me how can i do this.
thanks in advance.
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