Thread: Custom control information

What's the best way for me to keep 'information' with an instance of my custom control? Like at the moment, my controls have a class created on the WM_CREATE message and then I use SetWindowLong() to have a pointer to it. However, this makes the GWL_USERDATA useless for anything else ... and you can set it on the standard windows controls so that got me thinking that windows does it differently!

Now, the idea I'm working on now is to have an ever expanding array of a struct which uses the id and hwnd of a control as a unique id to store the class instance.. This way I can just search the array for the id and hwnd that match the control I'm painting and then retrieve the class pointer ...

Code:

typedef struct {
   
   HWND hwnd;
   int id;
   LONG *ptr;

}CLASSINFOSTRUCT, *lpCLASSINFOSTRUCT;

That would be the struct, or at least something similar to that. And then on the WM_PAINT message I'd just search the array looking for the matching struct members and then typecast the long pointer to the class type.

And this would be entered into the dynamic array after the class instance is instatiated.

Is this feasable??

Window memory:

SetWindowLong documentation:

Reserve extra window memory by specifying a nonzero value in the cbWndExtra member of the WNDCLASSEX structure used with the RegisterClassEx function.

nIndex - Specifies the zero-based offset to the value to be set. Valid values are in the range zero through the number of bytes of extra window memory, minus the size of an integer.

See example:
http://cboard.cprogramming.com/showt...threadid=49888

Use SetWindowLongPtr for pointers.

You can also use SetProp() but window memory is far safer and more efficient.

So SetProp allows me to say set the property "WindowClass" or whatever I want to a value??

If this is true I am forever in your debt!! You will have increased my productivity and reduced my headaches exponentially!!

It works!! You legend!! I have so many problems I can solve now because of you!! No more pointer related errors and crashes!

I can't thank you enough lol, ...

Cheers!

I wouldn't use SetProp()! Window memory, as used in the example, is far better.