Please help me what happend here- I know it is stupid but I want to know.
The output of the below code is April-18-2105. How did it pop up?
Private Sub CommandButton1_Click()
Dim firstDate As Date, secondDate As Date
firstDate = DateValue("Jun 19, 2010")
secondDate = DateValue("oct 29,1994")
MsgBox (firstDate + secondDate)
End Sub
Thanks in advance!
Dates are actually stored as numbers, so if we look at the numeric value for these dates:
CLng(datevalue("Jun 19, 2010")) '// 40348
CLng(datevalue("oct 29, 1994")) '// 34636
and add them together:
40348 + 34636 = 74984
and convert that number back to a date:
CDate(74984) '// 18/04/2105
Because it's 74,984 days after 00/01/1900
dates are numbers, formatted as dd/mm/yyyy, I think its the days from 31/12/1899, so that's what's happening. The result is 40348+34636=74984, which is 18/04/2105.
Excel stores the date as the number days after a specified date. As such the integer representing the date of 2010/06/19 is 40348 and the integer representing 1994/10/29 is 34636. When you add those integers together you get 74984 which is the integer that represents 2105/04/18.
The reference date does vary from mac to windows. I am running on windows and I did not change my reference date settings, That is where those integers came from. Mac uses January 2nd 1904 as day 1 and Windows uses January 1 1900 as day 1.
I am trying to populate a dropdown with No.of days generated by the system by the following code
Sub LoadDay()
Try
ddlDay.Items.Clear()
For i As Integer = 1 To System.DateTime.DaysInMonth(DateTime.Today.Year, ddlMonth.SelectedValue)
ddlDay.Items.Add(New ListItem(i.ToString(), i.ToString("00")))
Next
ddlDay.Items.Insert(0, New ListItem("--Select--", -999))
Catch ex As Exception
End Try
End Sub
Problem is, for the month of February it shows only 28 days because the following code generates Days on the basis of current year and this year isn't a leap year
System.DateTime.DaysInMonth(DateTime.Today.Year, ddlMonth.SelectedValue)
How can I fix it to always show 29 days for the month of Februaray?
You can use DayInMonth in DateTime
Dim dayinMonth As String
dayinMonth = System.DateTime.DaysInMonth(2012, 2)
This allow you to know the day in month for 2015 February. Parameter inside stand for year and month
I'd be interested in knowing what your requirment is that you have to be able to select invalid days, but, if you don't want your days to change based on the year, just create your own array of days. This leaves your intent a bit more clear than putting an arbitrary year in the DaysInMonth function.
Dim Days = {31,28,31,30,31,30,31,31,30,31,30,31}
ddlDay.Items.Clear()
For i As Integer = 1 To Days(ddlMonth.SelectedValue-1)
ddlDay.Items.Add(New ListItem(i.ToString(), i.ToString("00")))
Next
ddlDay.Items.Insert(0, New ListItem("--Select--", -999))
Hello Guys I want to make a Hotel Reservation system..
I have 3 combobox.. Lets say it is cboDays, cboMonth, cboYear.. When the form load I want to add items in cboDays, cboMonth, cboYears the days,month, and years. If I choose a month, cboDays will list all days depending if it is 31 days, 30 days, 29 days or 28 days. And also if I choose a leap year. Thank you guys in advance..
If I choose a month, cboDays will list all days
The built-in DateTime.DaysInMonth function calculates the number of days for a given year and month:
Dim numberOfDays = DateTime.DaysInMonth(year, month)
and it handles leap years too.
When the selected value of cboYear or cboMonth changes you need to update the values available in cboDays.
I am trying to return data for the last 24 months as of the end of last month. Only the initial month returns incorrect data, while all the other months are correct. I believe the issue is in the strBeginDate = section of the code. Any ideas what would be causing partially returned data for the initial month? Thank you very much.
Sub GetStaticApprovalRates_Slide6()
Dim strBeginDate
Dim strEndDate
strEndDate = Sheets("Instructions").Range("EndDate").Value
strBeginDate = DateAdd("m", -23, strEndDate) + 1
Sheets("Slide6Data").Select
It's hard to say exactly what's wrong based only on what you posted. But I do see that you are calculating the start date based on the end date, by only subtracting months. There is no allowance for days. So you might be missing some of that first month by not allowing for the early days of that first month.
That is , if end date occurs mid-month, I think your algorithm would cause start date to be mid-month also. Perhaps missing days 1-x of that first month.
I'm creating a report in MS SQL Server Reporting Services and need to set the default Start and End Date report parameters to be the first and last dates of the previous calendar month and need help.
The report is generated on the 2nd calendar day of the month and I need values for:
Previous Calendar Month
- first day
- last day
I've been working with DateAdd, but have not been successful at creating an Expression (in VB.NET as I understand it). I would really appreciate any help you can give me!
Randall, here are the VB expressions I found to work in SSRS to obtain the first and last days of any month, using the current month as a reference:
First day of last month:
=dateadd("m",-1,dateserial(year(Today),month(Today),1))
First day of this month:
=dateadd("m",0,dateserial(year(Today),month(Today),1))
First day of next month:
=dateadd("m",1,dateserial(year(Today),month(Today),1))
Last day of last month:
=dateadd("m",0,dateserial(year(Today),month(Today),0))
Last day of this month:
=dateadd("m",1,dateserial(year(Today),month(Today),0))
Last day of next month:
=dateadd("m",2,dateserial(year(Today),month(Today),0))
The MSDN documentation for the VisualBasic DateSerial(year,month,day) function explains that the function accepts values outside the expected range for the year, month, and day parameters. This allows you to specify useful date-relative values. For instance, a value of 0 for Day means "the last day of the preceding month". It makes sense: that's the day before day 1 of the current month.
These functions have been very helpful to me - especially in setting up subscription reports; however, I noticed when using the Last Day of Current Month function posted above, it works as long as the proceeding month has the same number of days as the current month. I have worked through and tested these modifications and hope they help other developers in the future:
Date Formulas:
Find the First Day of Previous Month:
DateAdd("m", -1, DateSerial(Year(Today()), Month(Today()), 1))
Find Last Day of Previous Month:
DateSerial(Year(Today()), Month(Today()), 0)
Find First Day of Current Month:
DateSerial(Year(Today()),Month(Today()),1)
Find Last Day of Current Month:
DateSerial(Year(Today()),Month(DateAdd("m", 1, Today())),0)
Dim thisMonth As New DateTime(DateTime.Today.Year, DateTime.Today.Month, 1)
Dim firstDayLastMonth As DateTime
Dim lastDayLastMonth As DateTime
firstDayLastMonth = thisMonth.AddMonths(-1)
lastDayLastMonth = thisMonth.AddDays(-1)
I'm not familiar with SSRS, but you can get the beginning and end of the previous month in VB.Net using the DateTime constructor, like this:
Dim prevMonth As DateTime = yourDate.AddMonths(-1)
Dim prevMonthStart As New DateTime(prevMonth.Year, prevMonth.Month, 1)
Dim prevMonthEnd As New DateTime(prevMonth.Year, prevMonth.Month, DateTime.DaysInMonth(prevMonth.Year, prevMonth.Month))
(yourDate can be any DateTime object, such as DateTime.Today or #12/23/2003#)
in C#:
new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1).AddMonths(-1)
new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1).AddDays(-1)
I was having some difficulty translating actual VB.NET to the Expression subset that SSRS uses. You definitely inspired me though and this is what I came up with.
StartDate
=dateadd("d",0,dateserial(year(dateadd("d",-1,dateserial(year(Today),month(Today),1))),month(dateadd("d",-1,dateserial(year(Today),month(Today),1))),1))
End Date
=dateadd("d",0,dateserial(year(Today),month(Today),1))
I know it's a bit recursive for the StartDate (first day of last month). Is there anything I'm missing here? These are strictly date fields (i.e. no time), but I think this should capture leap year, etc.
How did I do?
I was looking for a simple answer to solve this myself. here is what I found
This will split the year and month, take one month off and get the first day.
firstDayInPreviousMonth = DateSerial(Year(dtmDate), Month(dtmDate) - 1, 1)
Gets the first day of the previous month from the current
lastDayInPreviousMonth = DateSerial(Year(dtmDate), Month(dtmDate), 0)
More details can be found at:
http://msdn.microsoft.com/en-us/library/aa227522%28v=vs.60%29.aspx
This one will give you date no time:
=FormatDateTime(DateAdd("m", -1, DateSerial(Year(Today()), Month(Today()), 1)),
DateFormat.ShortDate)
This one will give you datetime:
=dateadd("m",-1,dateserial(year(Today),month(Today),1))
Dim aDate As DateTime = #3/1/2008# 'sample date
Dim StartDate As DateTime = aDate.AddMonths(-1).AddDays(-(aDate.Day - 1))
Dim EndDate As DateTime = StartDate.AddDays(DateTime.DaysInMonth(StartDate.Year, StartDate.Month) - 1)
'to access just the date portion
' StartDate.Date
' EndDate.Date