C Sharp Flags: Difference between revisions

From Leo's Notes
This page was last edited on 9 December 2012, at 19:06.
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  state = state | State.InService;
  state = state | State.InService;
   
   
<code>state</code> is now InService. The actual value of <code>state</state> is 0x04.
<code>state</code> is now InService. The actual value of <code>state</code> is 0x04.
 


=== Checking ===
=== Checking ===

Revision as of 19:06, 9 December 2012

Defining Flags

[Flags]
public enum  State {
   Idle = 0x01,
   Available = 0x02,
   InService = 0x04,
   
   Accelerating = 0x08,
   Decelerating = 0x10,
   Stopped = 0x20,
}

Notice that the flags are given values of powers of two.

Operations

Setting a Flag

Use the bit-wise OR operation to set (add) a flag. 

State state = State.Available;
state = state | State.Stopped;

state now has both Available and Stopped. The actual value of state is 0x22 (from 0x02 + 0x22)

Removing a Flag

Use the bit-wise XOR (^) operation to unset (remove) a flag. 

State state = State.Available | State.Stopped;
state = state ^ State.Available;
state = state ^ State.Stopped;
state = state | State.InService;

state is now InService. The actual value of state is 0x04.

Checking

Use the bit-wise AND operation to do checking. 

State state = State.Available | State.Stopped;

if (state & State.Idle == State.Idle) {
   // This will fail as state is set to Available and Stopped.
}