C# Discussion Boards - CodeProject

buchstaben2-May-08 4:11

2-May-08 4:11

Hello,

I'm stuck with the following issue:
let's say there is a DateTime 'timepoint', wich is passed in my method. I need to check now, whether timepoint's DayOfWeek is between 'fromDayOfWeek' and 'toDayOfWeek'.

that's what I've done so far:

protected override bool checkTimepoint(DateTime timepoint, DayOfWeek from, DayOfWeek to)
        {
            bool retValue;

            retValue = timepoint.DayOfWeek >= from && timepoint.DayOfWeek <= to;

            return retValue;
        }

This will work for ranges like Monday-Friday, Thursday-Wednesday, Wednesday-Wednesday, but it will fail for something like Saturday-Sunday, since Sunday (0) is lower than Saturday(6).

Any idea on how to logically implement this issue?

Thanks in advance.

Re: DateTime, DayOfWeek in range comparison

Urs Enzler2-May-08 4:22

Urs Enzler

2-May-08 4:22

We solved a similar problem by using a mapping from DayOfWeek to integer that returned 7 instead of 0 for Sunday.

This way your code would work, too.
Not very nice but it works.

For .net the week start on Sunday Frown | :(

-^-^-^-^-^-^-^-
no risk no funk

Re: DateTime, DayOfWeek in range comparison

buchstaben2-May-08 4:28

buchstaben

2-May-08 4:28

This will fix the problem for Saturday-Sunday, but it will not solve for Saturday-Tuesday.

Re: DateTime, DayOfWeek in range comparison

Spacix One2-May-08 4:54

Spacix One

2-May-08 4:54

why not:

protected override bool checkTimepoint(DateTime timepoint, DayOfWeek from, DayOfWeek to)
        {
            return timepoint.DayOfWeek >= from && timepoint.DayOfWeek <= to;
        }

-Spacix
All your skynet questions[^] belong to solved

I dislike the black-and-white voting system on questions/answers. Dead | X|

Re: DateTime, DayOfWeek in range comparison

buchstaben2-May-08 5:19

buchstaben

2-May-08 5:19

because this doesn't work.

testcase:

timepoint = new DateTime(2008,5,4);//sunday, 0
from = DayOfWeek.Friday; // 5
to = DayOfWeek.Tuesday; // 2

return 0 >= 5 && 0 <= 2;

return value is 'false', but sunday is between friday and tuesday!

Re: DateTime, DayOfWeek in range comparison [modified]

#realJSOP2-May-08 6:35

#realJSOP

2-May-08 6:35

You can use the CultureInfo class to set the first day of the week.

using System.Threading;

Thread.CurrentThread.CurrentCulture.DateTimeFormat.FirstDayOfWeek = DayOfWeek.Sunday;

So, set the first day of the week to whatever day you want, and then do your comparison.

protected override bool checkTimepoint(DateTime timepoint, DayOfWeek from, DayOfWeek to)
{
    Thread.CurrentThread.CurrentCulture.DateTimeFormat.FirstDayOfWeek = from;
    bool inRange = timepoint.DayOfWeek >= from && timepoint.DayOfWeek <= to;
    Thread.CurrentThread.CurrentCulture.DateTimeFormat.FirstDayOfWeek = DayOfWeek.Sunday;
    return inRange;
}

"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

modified on Friday, May 2, 2008 1:26 PM

Re: DateTime, DayOfWeek in range comparison

PIEBALDconsult2-May-08 7:39

PIEBALDconsult

2-May-08 7:39

Huh, interesting.

I wonder how it performs in a loop.

Re: DateTime, DayOfWeek in range comparison

#realJSOP2-May-08 7:45

#realJSOP

2-May-08 7:45

If performance is an issue (in a loop), you could always wait until the loop is done and reset to the proper 1st day at that point, thus saving n calls to do it in that checkpoint function.

Re: DateTime, DayOfWeek in range comparison

#realJSOP2-May-08 8:15

#realJSOP

2-May-08 8:15

Just thought I'd let you know I was completely wrong. Smile | :)

I posted a new response to the OP with the correct solution.

Re: DateTime, DayOfWeek in range comparison

PIEBALDconsult2-May-08 8:46

PIEBALDconsult

2-May-08 8:46

What? Say it ain't so! OMG | :OMG:

Re: DateTime, DayOfWeek in range comparison

PIEBALDconsult2-May-08 7:28

PIEBALDconsult

2-May-08 7:28

return ( true ) ;

Every timepoint falls between some DayOfWeek X and some DayOfWeek Y. Big Grin | :-D

buchstaben wrote:
Thursday-Wednesday

Did you mean that?

If you want Sunday to sort higher than Saturday, then you can simply add seven to it, but you'll need to store the values as integers rather than as the provided enum values.

int x = (int) timepoint.DayOfWeek ;
int y = (int) from ;
int z = (int) to ;

x += x==0 ? 7 : 0 ;
y += y==0 ? 7 : 0 ;
z += z==0 ? 7 : 0 ;

return ( x >= y && x <= z ) ;

but that's rather ugly.

Re: DateTime, DayOfWeek in range comparison

#realJSOP2-May-08 7:43

#realJSOP

2-May-08 7:43

You can set the first day of the week to be thursday, and then the comparison would work.

Re: DateTime, DayOfWeek in range comparison

#realJSOP2-May-08 8:10

#realJSOP

2-May-08 8:10

Ignore my first post. This is the best way (notice no bizarre culture crap going on):

DayOfWeek from = DayOfWeek.Thursday;
DayOfWeek to   = DayOfWeek.Tuesday;

DayOfWeek currentDay = DayOfWeek.Wednesday;

bool inRange = (currentDay >= from || currentDay <= to);

Notice that I'm using OR instead of AND. If you make currentDay Wednesday, inRange will be false. If you make it any other day, it will be true.

It's kind of pointless to do a Sunday-Saturday (or similar) comparison because any date will fall into the range. BTW, the comparison above also works for from=Saturday and to=Sunday.

Re: DateTime, DayOfWeek in range comparison

PIEBALDconsult2-May-08 9:13

PIEBALDconsult

2-May-08 9:13

I was just reviewing a method I wrote a few months back where I was checking to see if a value (integer) is between two others. I decided I needed more than a true/false, there are (currently) four result values:

[System.FlagsAttribute()]
public enum CheckRangeResult
{
    WithinStrictRange = 0
,
    Low               = 1
,
    High              = 2
,
    WithinLooseRange  = 3
}

Basically; given Min, Max, and Test we expect Min to be less than Max; and Test will be Lower than Min (1), Higher than Max (2), or WithinStrictRange (0).

But, when Min is greater than Max and Test is between Min and Max, both tests are true, yielding WithinLooseRange (3).

In the case presented here, when Min is greater than Max and Test is not between the values, that should translate to "true", but that's not currently supported.

I think I need to add value 4 to indicate that Min is greater than Max, then WithinLooseRange would have value 7. I'll think about it over the weekend.

Re: DateTime, DayOfWeek in range comparison

PIEBALDconsult2-May-08 18:55

PIEBALDconsult

2-May-08 18:55

It occurred to me late today that this might make a good Friday Programming Quiz. Big Grin | :-D

Re: DateTime, DayOfWeek in range comparison

#realJSOP3-May-08 0:26

#realJSOP

3-May-08 0:26

Maybe even two questions...

1) Given the following:

DayOfWeek startDay = DayOfWeek.Thursday;
DayOfWeek endDay = DayOfWeek.Monday;
DayOfWeek currentDay = DayOfWeek.Wednesday;

Write a C# publicly accessible function that determines whether or not the day falls between startDay and endDay. The function should work for any combination of startDay/endDay values, and should return a boolean value (true if in range, false if not in range).

Answer:

public bool DateInRange(DayOfWeek currentDay, DayOfWeek startDay, DayofWeek endDay)
{
    return (currentDay >= startDay || currentDay <= endDay);
}

2) Given the function above, change the function so that the class encapsulating it does not have to be instantiated in order to use the function.

Answer:

public static bool DateInRange(DayOfWeek currentDay, DayOfWeek startDay, DayofWeek endDay)
{
    return (currentDay >= startDay || currentDay <= endDay);
}

Re: DateTime, DayOfWeek in range comparison

PIEBALDconsult3-May-08 5:09

PIEBALDconsult

3-May-08 5:09

I don't think that works with the "normal" case where startDay < endDay.

It's also not a very general solution (which is no crime).

Given a number (value) line, two points on that line that define a range, and another point to test inclusion.

Normal
...........
1 > 2 < 3

Inverted (endponts not in normal order)
...........
4 < 5 > 6

The test value could be in any of the spots labeled 1 - 6.

We then need to assign true/false to these spots.

Clearly 2 yields true, while 1 and 3 yield false.

The question is about the inverted range;
The OP needs to assign true to 4 and 6, false to 5.
The code I wrote in November was designed to allow assigning true to 5, false to 4 and 6.

I have now modified my helper method (and enum) so it returns one of six values (it was four previously).
The application then needs to provide a method that handles the translation to true/false.

Re: DateTime, DayOfWeek in range comparison

#realJSOP4-May-08 4:02

#realJSOP

4-May-08 4:02

I think this should cover it then... Smile | :)

public static void DayInRange(DayOfWeek currentDay, DayOfWeek startDay, DayOfWeek endDay)
{
    if (startDay == endDay)
    {
        return true;
    }
    if (startDay < endDay)
    {
        return (currentDay >= startDay && currentDay <= endDay);
    }
    return (currentDay >= startDay || currentDay <= endDay);
}

Re: DateTime, DayOfWeek in range comparison

PIEBALDconsult4-May-08 5:34

PIEBALDconsult

4-May-08 5:34

That hurts my eyes.

(Not that I should talk. Blush | :O

)

Keypress event

D i x y2-May-08 2:38

D i x y

2-May-08 2:38

On keypress event i am disallow some of the some of the ascii value
like this

if (((e.KeyChar >= 91 && e.KeyChar <= 96) || e.KeyChar == 123 || e.KeyChar == 124 || e.KeyChar == 125 || e.KeyChar == 42 || e.KeyChar == 33 || e.KeyChar == 35 || e.KeyChar == 38 || e.KeyChar == 40 || e.KeyChar == 39 || e.KeyChar == 34 || e.KeyChar == 41 || e.KeyChar == 44 || e.KeyChar == 64 || e.KeyChar == 61 || e.KeyChar == 59 || e.KeyChar == 58 || e.KeyChar == 63 || e.KeyChar == 60 || e.KeyChar == 62) != false)<br />
                    {<br />
                        e.Handled = true;<br />
<br />
                    }

Now hat i want when user press space bar (Ascii value 32) then it will print '~' (Ascii value 126) in place of Ascii 32

if user enter
ABCD(SPACE)FGT THEN IT SHOULD PRINT
ABCD~FGT

Re: Keypress event

John Ad2-May-08 3:54

John Ad

2-May-08 3:54

Hi,

You may use the following code:

Private Sub TextBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyDown

If e.KeyCode = Keys.Space Then

e.SuppressKeyPress = True

Dim i As Integer

i = Me.TextBox1.SelectionStart

Me.TextBox1.Text = Me.TextBox1.Text + "~"

Me.TextBox1.SelectionStart = i + 1

End If

End Sub

Hope this helps.

Vinay
ComponentOne LLC.
www.componentone.com

Re: Keypress event

PIEBALDconsult2-May-08 8:22

PIEBALDconsult

2-May-08 8:22