Compare structures with C#

  • Thread starter Thread starter Gianco
  • Start date Start date
G

Gianco

Hello people

I have the following problem, probably it has an easy solution but I
don't know how to solve it:

There's a structure with many fields, with this structure I create a
variable named, for instance 'A'. Then I create a second variable
named 'B'. I would save the complete content of A into B with one or
few commands (not copying field by field) and, later, check if A is
different from B, with C/C++ is very easy, first I make a memcpy of A
into B then, to see if something is different I can use the memcmp

How can do it with C#?

If I write 'B = A' B is just referenced to A so when I change
something into A, B has always the same content of A. And when I
compare A to B with 'if (A == B)' it gives me always true...

Sorry for the banal question, thanks in advance to anyone can help me

Gianco
 
Gianco said:
I have the following problem, probably it has an easy solution but I
don't know how to solve it:

There's a structure with many fields, with this structure I create a
variable named, for instance 'A'. Then I create a second variable
named 'B'. I would save the complete content of A into B with one or
few commands (not copying field by field) and, later, check if A is
different from B, with C/C++ is very easy, first I make a memcpy of A
into B then, to see if something is different I can use the memcmp

How can do it with C#?

If I write 'B = A' B is just referenced to A so when I change
something into A, B has always the same content of A. And when I
compare A to B with 'if (A == B)' it gives me always true...

Sorry for the banal question, thanks in advance to anyone can help me
Click to expand...

It sounds like you're actually dealing with classes, not structs.

Could you post a short but complete program which demonstrates the
problem?

See http://www.pobox.com/~skeet/csharp/complete.html for details of
what I mean by that.
 
As you say doing something like 'B = A' means that A and B are pointing to
the same object. Thereafter A == B will always return true. It sounds like
you want to implement a "deep clone". Theres a debate a over whether you
should use the ICloneable interaface, I think the concensus is to avoid it
as it you cannot make a distinction between a shallow or deep copy.

Once you have a deep copy you can implement IComparable such that the
following will test for equality:

YourType A;
YourType B;

if(A.CompareTo(B) == 0)
{
//Same value;
}
 
Yes I supposed to work with a structure but it was declared as class,
now I changed something to use it as a structure and now make test if
the problem is solved. Thank you very much

Gianco
 
Back
Top