3

I have the following enums:

Days:

Sunday    1
Monday    2
Tuesday   4
Wednesday 8
Thursday  16
Friday    32
Saturday  64

WeekOfMonth

First     256
Second    512
Third     1024
Fourth    2048

I have, for example, the number 514 which is a sum of 512(Second) +2(Monday).

How can I get Second & Monday if I only have the number 514?

4

4 に答える 4

6

Assuming the following definitions:

[Flags]
enum Days {
  Sunday = 1,
  Monday = 2,
  Tuesday = 4,
  Wednesday = 8,
  Thursday = 16,
  Friday = 32,
  Saturday = 64
}

[Flags]
enum WeekOfMonth {
  First = 256,
  Second = 512,
  Third = 1024,
  Fourth = 2048
}

You can get the desired string using this code:

var value = (Int32) WeekOfMonth.Second + (Int32) Days.Monday; // 514
var days = (Days) (value & 0xFF);
var weekOfMonth = (WeekOfMonth) (value & 0xFF00);
var str = String.Format("{0} & {1}", weekOfMonth, days);

The variable str will contain Second & Monday as desired.

The [Flags] attribute is important if you want to be able to combine several Days values or WeekOfMonth values. For instance ((Days) 3).ToString() will return Sunday, Monday. If you forget the [Flags] attribute the string returned is 3.

于 2012-07-03T12:16:05.057 に答える
0

You could do a logical AND against each possible value. All values that return non zero are the ones that you want. 

var finalValue = ... // 512 -> 1000000010
var possibleValues = ... // array of flags [00000001, 000000010, 00000100, 00001000 ... ]

var appliedFlags = possibleValues.Where(x => x & finalValue == x).ToList();
于 2012-07-03T12:11:20.050 に答える
0

well I have an idea as I can see it seems to be binary sequence , so you can subtract this number 514 to the nearest binary which will be 512 then do the same process to the remaining until you got 0.

于 2012-07-03T12:15:27.700 に答える
0

Untested but should work: Take the number and divide it by the int value of the first WeekOfMonth value. The result will be a double, ignore everthing behind the comma. Now you have the value for WeekOfMonth. Afterwards use mod (%) division to get the rest of the division to get the remaining value which represtns your Days value.

In code:

var intValue = (int)WeekOfMonth.Second + (int)Days.Monday; //514
var weekOfMonth = (WeekOfMonth)Convert.ToInt32(intValue / (int)WeekOfMonth.First);
var day = (Days)(intValue % (int)WeekOfMonth.First);

I'm not sure if all the casts are working but it should give you the idea ;)

于 2012-07-03T12:20:59.867 に答える