MFC, Strange behavior when subclassing a static control in modal dialog

Strange behavior when subclassing a static control in modal dialog

Author	Message
dlio #1 / 6	Strange behavior when subclassing a static control in modal dialog I have written a MFC program which uses a modal dialog window. There is a static control in the dialog window. In order to paint on this static control, I subclassed it by using CMyStatic::SubclassDlgItem() and defined a OnPaint() in CMyStatic. (CMyStatic is derived from CStatic.) This works fine. But when I want this subclassed static control to do something special when it is clicked, I add a OnLButtonDown() in CMyStatic. To my surprise, CMyStatic::OnLButtonDown() is not called when I clicked on the static control. Instead, the CMyDialog::OnLButtonDown() is called. Why? Anybody can explain this for me?
Tue, 31 May 2005 08:38:44 GMT

Thomas Gaweh #2 / 6	Strange behavior when subclassing a static control in modal dialog Quote: >Anybody can explain this for me? You have to work with notifications here: 1. set the windows style of the class to SS_NOTIFY 2. enter something like ON_CONTROL_REFLECT(STN_CLICKED, OnClicked) 3. declare and implement afx_msg void OnClicked(); which is your OnlButtonDown thing. Normally CStatics are used only for navigation, you click it and the focus is set its neighbor. So the click has to handled by the parent! HTH --- Thomas Gawehns www.softwaremeister.com/daily_backup.html daily backup changed/new files into zip archives
Tue, 31 May 2005 09:17:09 GMT

Joseph M. Newcome #3 / 6	Strange behavior when subclassing a static control in modal dialog Not surprising. Do you know what "static" means? It means "DOES NOT RESPOND TO USER INPUT". Now, in later versions of Windows that has been modified somewhat; you can set the SS_NOTIFY flag. So that should solve your problem. You should not need SubclassDlgItem at all. Just create a member variable of your subclass in your modal dialog. If you already have CStatic c_MySpecialControl; then jjust hand-edit it to be CMyStatic c_MySpecialControl; read my essay on avoiding GetDlgItem. The same techniques apply here. Quote: >I have written a MFC program which uses a modal dialog window. >There is a static control in the dialog window. In order to >paint on this static control, I subclassed it by using >CMyStatic::SubclassDlgItem() and defined a OnPaint() in >CMyStatic. (CMyStatic is derived from CStatic.) This works >fine. But when I want this subclassed static control to do >something special when it is clicked, I add a OnLButtonDown() >in CMyStatic. To my surprise, CMyStatic::OnLButtonDown() is not >called when I clicked on the static control. Instead, the >CMyDialog::OnLButtonDown() is called. Why? >Anybody can explain this for me? Joseph M. Newcomer [MVP] Web: http://www3.pgh.net/~newcomer MVP Tips: http://www3.pgh.net/~newcomer/mvp_tips.htm
Tue, 31 May 2005 11:31:42 GMT

dlio #4 / 6	Strange behavior when subclassing a static control in modal dialog Thank you, Joseph. Your reply helps a lot. But I still have something I don't understand. I have defined a virtual function CMyStatic::WindowProc() which overrides CWnd::WindowProc(). In MFC, this means all the messages sent to the static control I subclassed will be received by CMyStatic::WindowProc(). I use some if-statement in it to check what messages it receives. It do receive WM_PAINT, but it don't receive WM_LBUTTIODOWN when I click on the static control. That's what really surprised me. I know "static" means "DOES NOT RESPOND TO USER INPUT". I think it behaves like that because its WndProc simply ignores messages related to user input. But in fact I found that the WndProc doesn't receive WM_LBUTTONDOWN at all. That's strange. Any inspirations? -- Quote: >Not surprising. Do you know what "static" means? It means "DOES NOT RESPOND TO USER >INPUT". Now, in later versions of Windows that has been modified somewhat; you can set the >SS_NOTIFY flag. So that should solve your problem. >You should not need SubclassDlgItem at all. Just create a member variable of your subclass >in your modal dialog. If you already have > CStatic c_MySpecialControl; >then jjust hand-edit it to be > CMyStatic c_MySpecialControl; >read my essay on avoiding GetDlgItem. The same techniques apply here. >>I have written a MFC program which uses a modal dialog window. >>There is a static control in the dialog window. In order to >>paint on this static control, I subclassed it by using >>CMyStatic::SubclassDlgItem() and defined a OnPaint() in >>CMyStatic. (CMyStatic is derived from CStatic.) This works >>fine. But when I want this subclassed static control to do >>something special when it is clicked, I add a OnLButtonDown() >>in CMyStatic. To my surprise, CMyStatic::OnLButtonDown() is not >>called when I clicked on the static control. Instead, the >>CMyDialog::OnLButtonDown() is called. Why? >>Anybody can explain this for me? >Joseph M. Newcomer [MVP] >Web: http://www3.pgh.net/~newcomer >MVP Tips: http://www3.pgh.net/~newcomer/mvp_tips.htm
Wed, 01 Jun 2005 10:42:57 GMT

Jeff Partc #5 / 6	Strange behavior when subclassing a static control in modal dialog Quote: > I have defined a virtual function CMyStatic::WindowProc() which > overrides CWnd::WindowProc(). In MFC, this means all the messages > sent to the static control I subclassed will be received by > CMyStatic::WindowProc(). I use some if-statement in it to check what > messages it receives. It do receive WM_PAINT, but it don't receive > WM_LBUTTIODOWN when I click on the static control. That's what > really surprised me. > I know "static" means "DOES NOT RESPOND TO USER INPUT". I think it > behaves like that because its WndProc simply ignores messages related > to user input. But in fact I found that the WndProc doesn't receive > WM_LBUTTONDOWN at all. That's strange. > Any inspirations? See the "Static Control Default Message Processing" subheading at the following URL... http://msdn.microsoft.com/library/default.asp?url=/library/en-us/shel... ...Under the WM_NCHITTEST message entry we find that the control, "...Returns HTCLIENT if the control style is SS_NOTIFY; otherwise, returns HTTRANSPARENT". -- Jeff Partch [VC++ MVP]
Wed, 01 Jun 2005 12:42:48 GMT

dlio #6 / 6	Strange behavior when subclassing a static control in modal dialog Thank you very much. I got it. -- Quote: >> I have defined a virtual function CMyStatic::WindowProc() which >> overrides CWnd::WindowProc(). In MFC, this means all the messages >> sent to the static control I subclassed will be received by >> CMyStatic::WindowProc(). I use some if-statement in it to check what >> messages it receives. It do receive WM_PAINT, but it don't receive >> WM_LBUTTIODOWN when I click on the static control. That's what >> really surprised me. >> I know "static" means "DOES NOT RESPOND TO USER INPUT". I think it >> behaves like that because its WndProc simply ignores messages related >> to user input. But in fact I found that the WndProc doesn't receive >> WM_LBUTTONDOWN at all. That's strange. >> Any inspirations? >See the "Static Control Default Message Processing" subheading at the >following URL... >http://msdn.microsoft.com/library/default.asp?url=/library/en-us/shel... >...Under the WM_NCHITTEST message entry we find that the control, >"...Returns HTCLIENT if the control style is SS_NOTIFY; otherwise, >returns HTTRANSPARENT".
Wed, 01 Jun 2005 13:34:44 GMT

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