detecting the 30 minutes interval in time scheduling

[psyke]

Hi! I have a problem in detecting the 30 minutes interval in time scheduling like for example i have a combobox(starting_time) and combobox2(endtime) and I select there 9:30-10:00 it has 30 minutes I want to show a message box that I should be 1 hour .Can you help me? Thanks in advance ^^

[cicatrix]

DateTimes can be added subtracted and compared:

Dim HalfAnHour As TimeSpan = TimeSpan.FromMinutes(30)
        Dim d1 As DateTime = DateTime.Parse("12:30")
        Dim d2 As DateTime = DateTime.Parse("12:26")
        Dim d3 As DateTime = DateTime.Parse("11:59")
 
 
        If d2 - d1 < HalfAnHour Then
            MsgBox("Less than 30 mins")
        End If
 
        If d2 - d3 > HalfAnHour Then
            MsgBox("More than 30 mins") ' Never called
        End If

[psyke]

But how can i insert it there the combo box? the name of my combo box is starting_time and end_time? Thanks!

[cicatrix]

Put combobox1 and combobox2 on a form

' Put combobox1  and combobox2 on a form
Public Class Form1
 
    Dim StartTime As DateTime
    Dim EndTime As DateTime
    Dim halfanhour As TimeSpan = TimeSpan.FromMinutes(30)
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim FiveMins = TimeSpan.FromMinutes(5)
        Dim t As DateTime = DateTime.Parse("0:00")
        For x = 0 To 47
            ComboBox1.Items.Add(String.Format("{0:hh:mm}", t))
            ComboBox2.Items.Add(String.Format("{0:hh:mm}", t))
            t += FiveMins
        Next
    End Sub
 
    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        StartTime = DateTime.Parse(ComboBox1.Items(ComboBox1.SelectedIndex).ToString)
    End Sub
 
    Private Sub ComboBox2_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ComboBox2.SelectedIndexChanged
        EndTime = DateTime.Parse(ComboBox2.Items(ComboBox2.SelectedIndex).ToString)
        Dim diff As TimeSpan = EndTime - StartTime
        Dim msg As String
        msg = String.Format("Start time:{0:hh:mm}{1}End time:{2:hh:mm}{1}Difference:{3} minutes", _
                             New Object() {StartTime, Environment.NewLine, EndTime, diff.Minutes})
 
        MsgBox(msg)
    End Sub
 
End Class

[psyke]

Thank you very much. I have 1 more problem on how to detect a conflict schedule i have this attribute:

* ScheduleID = 10002
* StartTime = 9:00 AM
* EndTime = 10:00 AM
* Day = MTH
* Room = AVR
* Course = BSN

I'm using MSSQL Server 2008. Can you help me also in this? because this is my last problem so that my system finish.. Thanks

[cicatrix]

what conflict schedule? what attribute? where? conflict with what?

[psyke]

MS SQL2008
I have a time table day(nchar),course(nchar),room(nchar),starting_time(time),end_time(time)
I add an Entry:
day=WF
course=BSN
room=AVR
starting_time=7:00am
end_time=8:00am

VS2008

Now if inserted
day=WF
course=BSN
room=AVR
starting_time=7:30am
end_time=8:30am

it will show a msgbox conflict and it will not insert in the database but if not conflict then it will save on the database

[cicatrix]

This will require quite a bit of coding, by the way.

Let's assume that our New (N) time interval has its start (N_s) and end (N_e), and accordingly you have an Existing (E) time interval that has its start (E_s) and end (E_e). Then you will have to check the following conditions before evaluating the result:

≤ - means less than or equal
≥ - means greater than or equal

((N_e ≥ E_s) AND (N_e ≤ E_e))
OR
((N_s ≤ E_s) AND (N_e ≥ E_e))
OR
((N_s ≤ E_s) AND (N_e ≥ E_s))
OR
((N_s ≥ E_s) AND (N_s ≤ E_e))



Well, I hope that logic didn't fail me this time. It's even possible that this condition can be simplified, but my head aches to go through this again.
You will have to query all Starting_time and end_time fields from your table and perform the abovementioned checks with each pair before you can tell if there are any conflicts. Alternatively you can construct an SQL query with these conditions and check if it returns any records. The number of records returned will be the number of conflicts detected.

[psyke]

Here's my code:
Dim con As New SqlClient.SqlConnection("Data source=NINOPADAMA;initial catalog=classScheduling;Integrated Security=True")
Dim cmd As New SqlCommand()
cmd.Connection = con


Dim RDR As SqlDataReader
con.Open()


cmd.CommandText = "Select * from timeload where (('" & ComboBox1.Text & "' Between stime And etime) Or ('" & ComboBox2.Text & "' Between stime And etime))"
RDR = cmd.ExecuteReader


If RDR.HasRows = True Then
MsgBox("Conflict")
Else
MsgBox("Success")
End If

In my table stime(time),etime(time)


My school starts 7:00AM to 9:00PM. the code for the conflict works if i had an input of any time from 7am-4pm but if i set it in any time from 5pm til 9pm it prompts me a msgbox saying success rather than an error mssge. Can you help me with this?

[cicatrix]

Here is the four possible variants of conflict:

A.
New:           ***
         ----------------------------> Time axis
Existing:   **********

B.
New:        *************
         ----------------------------> Time axis
Existing:      ****

C.
New:               ********
         ----------------------------> Time axis
Existing:      ********


D.
New:          ********
         ----------------------------> Time axis
Existing:          ********

Your SQL should just check all four conditions to be false.

[psyke]

I'm not familiar with that code? Can you give another way? Thanks

[cicatrix]

It's not a code, it's a diagram.

[psyke]

Can you modify my code? And add this attribute day,course,room
to become day,course,room,starting_time,end_time?

When I test my code its working ,the data type I used in starting_time and end_time is datetime but like I've said the conflict works if i had an input of any time from 7am-4pm but if i set it in any time from 5pm til 9pm it prompts me a msgbox saying success rather than an error mssge