Subclassing The Desktop
-
This isn't a .NET rule - it's a Windows rule. ;) What are you trying to accomplish? It's likely there is another way to do it.
"Blessed are the peacemakers, for they shall be called sons of God." - Jesus
"You must be the change you wish to see in the world." - Mahatma GandhiI am trying to draw on the desktop. I need to be notified of the WM_Paint message for the desktop otherwise what I draw is erased on the next WM_Paint. Thanks for your help Forever Developing
-
I am trying to draw on the desktop. I need to be notified of the WM_Paint message for the desktop otherwise what I draw is erased on the next WM_Paint. Thanks for your help Forever Developing
-
And why do you need to draw on the desktop? ;)
"Blessed are the peacemakers, for they shall be called sons of God." - Jesus
"You must be the change you wish to see in the world." - Mahatma GandhiJust for fun. Forever Developing
-
Just for fun. Forever Developing
It might not be what you want to do, but check out the ControlPaint class.
-
I am trying to draw on the desktop. I need to be notified of the WM_Paint message for the desktop otherwise what I draw is erased on the next WM_Paint. Thanks for your help Forever Developing
I do not know of a way in .NET but in Win32 you can probably do it with a DLL and HookProc. It will map your DLL into the system memory space were you can trap the messages. I used this method in the old days to communicate with the AOL software and capture its messages. Rocky Moore <><
-
I do not know of a way in .NET but in Win32 you can probably do it with a DLL and HookProc. It will map your DLL into the system memory space were you can trap the messages. I used this method in the old days to communicate with the AOL software and capture its messages. Rocky Moore <><
It's best not to deal with system-wide hooks, but it can be done. The main thing is that if your DLL hangs, the system hangs. (I've had experience with that! :( ) You might also look into a journal hook, although it may not work for paint messages.
"Blessed are the peacemakers, for they shall be called sons of God." - Jesus
"You must be the change you wish to see in the world." - Mahatma Gandhi -
It's best not to deal with system-wide hooks, but it can be done. The main thing is that if your DLL hangs, the system hangs. (I've had experience with that! :( ) You might also look into a journal hook, although it may not work for paint messages.
"Blessed are the peacemakers, for they shall be called sons of God." - Jesus
"You must be the change you wish to see in the world." - Mahatma Gandhijdunlap wrote: The main thing is that if your DLL hangs, the system hangs. Makes debugging interesting ;) Actually, I never had any problems with System Wide Hooks. The code required to implement them is not complex and as long as you keep to only what is required and do not pile a lot into the DLL, things should be fine. You need to watch when you attach and detach from different applications, a goof in there can cause strange things to happen ;) Thre are not anything to be afriad of though, I used them for years with the application I mentioned and never recieved on issue about it crashing their system. Rocky Moore <><
-
It's best not to deal with system-wide hooks, but it can be done. The main thing is that if your DLL hangs, the system hangs. (I've had experience with that! :( ) You might also look into a journal hook, although it may not work for paint messages.
"Blessed are the peacemakers, for they shall be called sons of God." - Jesus
"You must be the change you wish to see in the world." - Mahatma Gandhijdunlap wrote: It's best not to deal with system-wide hooks, but it can be done. FYI: According to MSDN you can't perform a global hook under the .NET Framework : Knowledge Base Article - 318804[^] -Nick Parker
-
jdunlap wrote: It's best not to deal with system-wide hooks, but it can be done. FYI: According to MSDN you can't perform a global hook under the .NET Framework : Knowledge Base Article - 318804[^] -Nick Parker
"To install a global hook, a hook must have a native dynamic-link library (DLL) export to inject itself in another process that requires a valid, consistent function to call into. This requires a DLL export, which .NET Framework does not support. " But this supported by MC++. I have a single dll with exports and a manifest ad can be used by bith managed and unmanaged apps, just as long as you have .NET installed, the process is transparent to unmanaged code. So IMO its should be a trivial task to make an interface for a global hook. I havent done anything like this, am I correct? leppie::AllocCPArticle(Generic DFA State Machine for .NET);
-
"To install a global hook, a hook must have a native dynamic-link library (DLL) export to inject itself in another process that requires a valid, consistent function to call into. This requires a DLL export, which .NET Framework does not support. " But this supported by MC++. I have a single dll with exports and a manifest ad can be used by bith managed and unmanaged apps, just as long as you have .NET installed, the process is transparent to unmanaged code. So IMO its should be a trivial task to make an interface for a global hook. I havent done anything like this, am I correct? leppie::AllocCPArticle(Generic DFA State Machine for .NET);
leppie wrote: But this supported by MC++. I have a single dll with exports and a manifest ad can be used by bith managed and unmanaged apps, just as long as you have .NET installed, the process is transparent to unmanaged code. I guess what they mean is that the .NET Framework doesn't natively support this type of functionality (strictly within the Framework itself), I believe what you have is a "work-around". Then again, I could be completely wrong. :-D -Nick Parker