THANK YOU! I really appreciate the thorough response. This makes a lot of
sense - I've never worked with bitwise operators before, but I now certainly
see their value.
I'm hoping my final question is simple -- what indicates that
CodeMemberMethod.Attributes requires bitwise operations or that it allows
for more than one bit to be set? The word "attributes" below is plural, but
is there another clear indication? I'm looking at the class library and
don't see anything about the Attributes property allowing for multiple
values. I would assume that by NOT specifying this more clearly, it would
only allow one ... but perhaps I just need to watch for the plural part.
Thanks again. - Mark
**** FROM CLASS LIBRARY ***
CodeTypeMember.Attributes Property [C#]
Gets or sets the attributes of the member.
[C#]
public MemberAttributes Attributes {get; set;}
Property Value
One of the MemberAttributes values that indicates the attributes of the
member. The default value is Private | Final.
Remarks
This property is used to specify attributes of the type member. Some types
of attributes are Access (Public/Private) and Scope (Final/Override).
**** END CLASS LIBRARY ***
"Derek Harmon" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> "Mark" <(E-Mail Removed)> wrote in message
news:%(E-Mail Removed)...
> > 1. What is the purpose of the |= operator here?
>
> |= is a special C# assignment operator that combines assignment (=) with a
bitwise-OR (|).
> You may be more familiar with the more common +=,
>
> sum += item.Value;
>
> which is equivalent to,
>
> sum = sum + item.Value;
>
> Similarly,
>
> codeMethod.Attributes |= MemberAttributes.Static;
>
> is equivalent to,
>
> codeMethod.Attributes = codeMethod.Attributes |
MemberAttributes.Static;
>
> which says the Attributes are the same as they are originally, but the
Static
> flag is turned on (if it isn't already on).
>
> > 2. I'd like to make it static AND public. It appears to only allow you
to
> > do one ... if you do both in a row, the second prevails. The default
> > behavior is private and an instance method. Is there a workaround?
>
> Attributes is a [Flags] enumeration. If you're familiar with C
programming, you
> may have encountered enums that were used to create "bitmasks" such as,
>
> enum MyFlags {
> XMIT_CHAR = 1,
> RECV_CHAR = 2,
> CARRIER = 4
> };
>
> and in this case you could have an int variable that could contain none-,
one-,
> two- or all three- of these binary bit flags. You would turn ON a flag by
using
> a bitwise-OR operation, or you would turn OFF a flag by using a bitwise
AND
> operation. For example (this is in C pseudocode),
>
> /* auxStatReg is 5, it has bits 0 and 2 turned ON. */
> int auxStatReg = XMIT_CHAR | CARRIER;
>
> /* auxStatReg is 4, bit 0 has been turned OFF. */
> auxStatReg = auxStatReg & CARRIER;
>
> /* auxStatReg is tested to see whether bit 2 is turned ON. */
> if ( ( auxStatReg & CARRIER ) == CARRIER )
> /* we have carrier. */
> else
> /* no carrier. */
>
> These operations continue to be used in C#, in fact they've been improved
and
> enum declarations that have a [FlagsAttribute( )] applied to them
automatically
> support these sorts of operations with strong compile-time type checking
(and
> meaningful identifier names when debugging in the IDE).
>
> In this case, Attributes is of type MemberAttributes which is a [Flags]
enum.
> That means you can turn on multiple flags, but working with them means you
> need to be familiar with using the bitwise-OR and -AND operations.
>
> > CodeMemberMethod method = new CodeMemberMethod();
> > method.Name = "MyMethod";
> > method.Attributes = MemberAttributes.Static;
> > method.Attributes = MemberAttributes.Public; //This one overwrites the
> > other!!
>
> You can use the bitwise-OR operator, |, to turn on both flags.
>
> // Makes the Attributes Static and Public (overwrites previous Final,
Private
> // flag selections).
> //
> method.Atributes = MemberAttributes.Static | MemberAttributes.Public;
>
> If you're familiar with Set Theory, think of OR as performing a Union, and
> think of AND as performing an Intersection.
>
>
> Derek Harmon
>
>
|
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