Question about IntPtr

[Ron Vecchi]

I am creating my own MainMenu control similar to VS.Net. (yes I know theirs
some out their).
I have predominatly been a web developer for about 5 years and am playing
with Windows forms. So this should help me learn.

My question is about IntPtr.
Basically what is it, I know its a pointer but what is a pointer.(of course
I know it points to something but how) .
In my MenuControl I needed a graphics object in my OnPaint override.

This works great but I dont know why...
//////////////////////////////////
protected override void OnPaint(PaintEventArgs e) {

this.rmm_Graphics = Graphics.FromHwnd(this.Parent.Handle);

}

I think by understanding what pointers are and how they work I will
understand exactly how I extracted the grapics object from my containing
form.
Does any one know of some newbie windows resopurces that expain this on a
moronic level.


Thanks,

 

[Mountain Bikn' Guy]

Any intro to computer science text book using C. For example, mine was
"Introduction to Computer Science Using C" by Roger Eggen. Highly
recommended.

The pointer contains a memory address. 32 bit operating systems use 32 bit
ints to address each available memory position. Conceptually, you can start
to get a handle on it by thinking of your street address "pointing" to your
house's physical location. Someone writes your address on a box and the USPS
delivers it to you. That's what a pointer can do.

Of coursed managed code complicates this because your "house" is moved when
the garbage collector runs.

 

[Ron Vecchi]

ok, I think I understand. using the IntPtr is like saying "at this memory
location"
so in my case am I abstractly saying "give me the graphics object from the
form at this memory location"

Oh, also Im an idiot, I didn't realize that the PaintEventArgs supplied a
graphics object. Although that didn't stop me from still wondering about
the IntPtr. It just accelerated it.

Any intro to computer science text book using C. For example, mine was
"Introduction to Computer Science Using C" by Roger Eggen. Highly
recommended.

The pointer contains a memory address. 32 bit operating systems use 32 bit
ints to address each available memory position. Conceptually, you can start
to get a handle on it by thinking of your street address "pointing" to your
house's physical location. Someone writes your address on a box and the USPS
delivers it to you. That's what a pointer can do.

Of coursed managed code complicates this because your "house" is moved when
the garbage collector runs.

 

[Mountain Bikn' Guy]

Personally, I would first try to understand pointers outside the context of
dotnet. I wouldn't try to understand IntPtr without understanding a plain
generic pointer. That's just my opinion. BTW, the text book I mentioned is
available for $15 used at
http://www.amazon.com/exec/obidos/t...002-8702177-3519244?v=glance&s=books&n=507846

But I'm sure you can find coverage of this topic by searching on Google.

In general, a pointer holds the address of another variable. It's that
simple.

ok, I think I understand. using the IntPtr is like saying "at this memory
location"
so in my case am I abstractly saying "give me the graphics object from the
form at this memory location"

Oh, also Im an idiot, I didn't realize that the PaintEventArgs supplied a
graphics object. Although that didn't stop me from still wondering about
the IntPtr. It just accelerated it.

Any intro to computer science text book using C. For example, mine was
"Introduction to Computer Science Using C" by Roger Eggen. Highly
recommended.

The pointer contains a memory address. 32 bit operating systems use 32 bit
ints to address each available memory position. Conceptually, you can start
to get a handle on it by thinking of your street address "pointing" to your
house's physical location. Someone writes your address on a box and the USPS
delivers it to you. That's what a pointer can do.

Of coursed managed code complicates this because your "house" is moved when
the garbage collector runs.

on