How to access to struct member?

[SL82]

Please help me.
I need to know how can I access to struct member if I know only struct address.
For example, something like this:

STRUC MY_STRUCT
x dd ?
y dd ?
ENDS MY_STRUCT
...
pop edi ; edi directs to variable of type MY_STRUCT
add edi, offset MY_STRUCT.y

Last string don't want to be compiled.

This problem is terrible for me, because I need to write a program on tasm with classes. I had wrote some non-static methods and have to calculate (by hands) addresses of class members in each methods. It's terrible!
I think, must be a good access method. Am I right?

 

[TessaBonting]

make this:

add edi, offset MY_STRUCT.y

this:

add edi,[MY_STRUCT.Y+edi]

and it will work fine

Tessa