Und was bringt es wenn du weißt, dass er die Maustaste noch nicht losgelassen hat?
Gefunden habe ich das hier:
CButton
The CButton class provides the functionality of Windows button controls. A button control is a small, rectangular child window that can be clicked on and off. Buttons can be used alone or in groups and can either be labeled or appear without text. A button typically changes appearance when the user clicks it.
Typical buttons are the check box, radio button, and pushbutton. A CButton object can become any of these, according to the button style specified at its initialization by the Create member function.
In addition, the CBitmapButton class derived from CButton supports creation of button controls labeled with bitmap images instead of text. A CBitmapButton can have separate bitmaps for a button's up, down, focused, and disabled states.
You can create a button control either from a dialog template or directly in your code. In both cases, first call the constructor CButton to construct the CButton object; then call the Create member function to create the Windows button control and attach it to the CButton object.
Construction can be a one-step process in a class derived from CButton. Write a constructor for the derived class and call Create from within the constructor.
If you want to handle Windows notification messages sent by a button control to its parent (usually a class derived from CDialog), add a message-map entry and message-handler member function to the parent class for each message.
Each message-map entry takes the following form:
ON_Notification( id, memberFxn )
where id specifies the child window ID of the control sending the notification and memberFxn is the name of the parent member function you have written to handle the notification.
The parent’s function prototype is as follows:
afx_msg void memberFxn( );
Potential message-map entries are as follows:
Map entry Sent to parent when...
ON_BN_CLICKED The user clicks a button.
ON_BN_DOUBLECLICKED The user double-clicks a button.
If you create a CButton object from a dialog resource, the CButton object is automatically destroyed when the user closes the dialog box.
If you create a CButton object within a window, you may need to destroy it. If you create the CButton object on the heap by using the new function, you must call delete on the object to destroy it when the user closes the Windows button control. If you create the CButton object on the stack, or it is embedded in the parent dialog object, it is destroyed automatically.
#include <afxwin.h>
Vielleicht hilft es ja obwohl da auch nur klick und doppelklick steht.
EDIT: Kannst ja bei WM_LBUTTONUP auch eine Variable setzen, und wenn die nicht true ist oder einen bestimmten Wert hat im Vergleich zu einer anderen Variable bei WMLBUTTENDOWN weißt du ja dass die Maustaste noch nicht wieder losgelassen wurde. ;)