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# Storing a value that corresponds to a users selection

Posted on 2011-09-07
Medium Priority
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I have a schedule where the user can specify a job should run every n weeks, It also allows them to specify on what days of the weeks they would like it to run ie

Sun, Mon & Tuesday

Ideally I want to save their selection as a single integer, is this possible if I assign each day a binary figure.

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Question by:rocky050371
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Accepted Solution

CSIPComputing earned 1336 total points
ID: 36494963
Storing which days of the week the user selected is simple.

Use Binary.

Assign each day a bit (i.e. bit 0=Mon, Bit 1=Tues, Bit 2=Wed, Bit3=Thurs, Bit 4 = Fri, Bit 5 = Sat, Bit 6=Sun), then you can "Translate" as follows: (see the code snippet)

Monday, Tuesday, Thursday becomes 1 + 2 + 8 = 11
Wed, Fri, Sun becomes 4 + 16 + 64 = 84

You can encode any number of days selected, and of course DE-code them in this way.

The every "N" weeks is just a number anyway... i.e. 1 = Every week, 2 = Every fortnight, 4=Every month etc.

So using 2 integers, you can encode your entire schedule.
Hope that makes sense!

n/a  Sun  Sat Fri Thu Wed Tue Mon
128   64   32  16  8   4   2   1
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Author Comment

ID: 36495084
How would you recommend I decode, say for example 11 is in the database, do it via a select case?
0

LVL 10

Expert Comment

ID: 36495231
It depends on how you know what "day" it is in your code, and what you need to compare with.

I'm not a code guru (as you'll see below), but in my dim and distant past, I'd have done something like this, and I'm sure it can be translated into a Case statement:

Dim strToday as String = "Wed" (or whatever/however you know today)
Dim intSched as Integer = #value read from wherever you're storing it#
Dim intShouldIRun as Integer

If intSched >64 then
if strToday="Sun" then intShouldIRun=1
intSched=intSched-64
End If

If intSched >32 then
if strToday="Sat" then intShouldIRun=1
intSched=intSched-32
End If

If intSched >16 then
if strToday="Fri" then intShouldIRun=1
intSched=intSched-16
End If

..etc...

if intShouldIRun<>0 then
run my scheduled job
End If
0

LVL 40

Expert Comment

ID: 36500526
An alternative would be to use a flagged Enum, typically in the declaration section of a Module:

<Flags()> Enum Days
Sunday = 1
Monday = 2
Tuesday = 4
Wednesday = 8
Thursday = 16
Friday = 32
Saturday = 64
End Enum

0

LVL 40

Assisted Solution

Jacques Bourgeois (James Burger) earned 664 total points
ID: 36500549
Sorry, hit Submit by mistake before finishing.

An alternative would be to use a flagged Enum, typically in the declaration section of a Module:
<Flags()> Enum Days
Sunday = 1
Monday = 2
Tuesday = 4
Wednesday = 8
Thursday = 16
Friday = 32
Saturday = 64
End Enum
To use it, you create a variable. The nice thing is that Intellisense will display the possible values when you try to assign to it:
Dim selection As Days
selection = Days.Monday Or Days.Friday Or Days.Sunday
An enumeration is an integer by default. Depending on how your environment is set, you might be able to use it as any other Integer. If you have errors, simple use is as CInt(selection).

To decode it, you use And in an If or a Select Case:
If CBool(selection And Days.Monday) Then
Debug.WriteLine("Monday was selected")
End If
Or you could use that nice little feature of flagged enumerations:
MessageBox.Show(selection.ToString("g"))
The result will be "Sunday, Monday, Friday".
0

Author Comment

ID: 36501546
If the user selected Monday, Tuesday, Wednesday + Friday

Then I store away the corresponding total 46, when I retrieve how will I know those four days have been selected?

Not sure how (selection And Days.Monday) seems to work either

I appreciate the help though this is definitely heading in the right direction

0

LVL 10

Expert Comment

ID: 36501650
OK, Using Jame's day definitions, and the total of 46, but my method of decoding (as I don't know CBOOL functions either),

46<64, so Saturday is NOT selected
46=>32 so Friday IS selected - Subtract 32
14<16 so Thursday is NOT selected
14=>8 so Wednesday IS selected - Subtract 8
6=>4 so Tuesday IS Selected - Subtract 4
2=>2 so Monday IS Selected - Subtract 2
0<1 so Sunday is NOT Selected.

Sorry I can't write the code for you, but hopefuilly the above makes sense!
0

LVL 40

Expert Comment

ID: 36504002
@CISPComputing

The AND operator on a flagged enumeration returns an Integer. When the project is configured for strict type checking, you cannot use an Integer with If, you need a Boolean.

CBool is the VB method to convert to a Boolean. Similar to Convert.ToBoolean(), but more efficient because the conversion is compiled into the assembly instead of being called at runtime.

0

Author Comment

ID: 36504942
So I take it I simply check my stored value (46 as a integer) against each flag element top determine what has been selected

0

LVL 40

Expert Comment

ID: 36506846
Yes you do.
0

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Assisted Solution

CSIPComputing earned 1336 total points
ID: 36510827
Sounds like a plan :-)
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