To check if for example AB is set I can do this:
if((letter & Letters.AB) == Letters.AB)
Is there a simpler way to check if any of the flags of a combined flag constant are set than the following?
This checks that both A and B are set, and ignores whether any other flags are set.
if((letter & Letters.A) == Letters.A || (letter & Letters.B) == Letters.B)
This checks that either A or B is set, and ignores whether any other flags are set or not.
This can be simplified to:
if(letter & Letters.AB)
Here's the C for binary operations; it should be straightforward to apply this to C#:
enum {
A = 1,
B = 2,
C = 4,
AB = A | B,
All = AB | C,
};
int flags = A|C;
bool anything_and_a = flags & A;
bool only_a = (flags == A);
bool a_and_or_c_and_anything_else = flags & (A|C);
bool both_ac_and_anything_else = (flags & (A|C)) == (A|C);
bool only_a_and_c = (flags == (A|C));
Incidentally, the naming of the variable in the question's example is the singular 'letter', which might imply that it represents only a single letter; the example code makes it clear that its a set of possible letters and that multiple values are allowed, so consider renaming the variable 'letters'.