Programming Forums > Application Development > Visual Basic .NET

sackarias · Nov 19th, 2007, 3:36 PM

I'm writing a program that's interacting with a database that has two tables. The table relevant to my question is my customer table, which has a Date/Time field that expresses the current customers account expiration date.

I'm having trouble comparing a customer's expiration date to another date object to verify if their account expired.

This code checks if a Dvd is checked out, if it isn't, ask the user's account number. Next I check (where error keeps occuring) if the expiration date is prior to todays date, thus making it valid, but it doesn't work that way. In which ways can you go about comparing two dates? Maybe I missed a certain method pertaining to comparing dates, I saw a compareTo, nothing like an isLessThen or similar. Any help would be greatly appreciated, thanks a lot. Also, when I copied my code over it automatically put returns so it's sort of hard to read, sorry for that.

(Toggle Plain Text)

If dbSetAdapter.Tables("Dvds").Rows(index).Item("CheckedOutBy") = "XXXXXXX" Or 0 Then
            response = InputBox("Enter your account number", "Account Number")
            If findAccount(response, 0) <> -1 Then
                accountIndex = findAccount(response, 0) 'account found, put index in variable
                If cusSet.Tables("Customer").Rows(accountIndex).Item("ExpirationDate") < Date.Today Then  'ERROR HERE, How to compare if one date is "less then" another
                    MessageBox.Show("not expired")
                End If
            Else
                MessageBox.Show("Account number does not exist")
            End If
        Else
            MessageBox.Show("This DVD is checked out.")
        End If

DaWei · Nov 19th, 2007, 3:58 PM

You can deal with dates in a number of different ways. If you think hard enough and work hard enough, you can even deal with them correctly.

My approach is to convert evey date that is to be subjected to manipulation to a form that represents a a numerical value expressing time elapsed since some benchmark time in the past.

You, too, can do this. It doesn't much matter whether you read the material pertaing to VB, or to PHP, or to C, or to a non-language entity such as an operating system. Read, understand, adapt, and write.

SydneyMcConnell · Jan 9th, 2008, 12:46 PM

Enclose cusSet.Tables("Customer").Rows(accountIndex).Item("ExpirationDate") in a CDate, and see if that solves the issue. In some cases, it may not implicitly convert an object in an equation when you're working with Data, and so it may just stay as an object.

It should be like:

(Toggle Plain Text)

If CDate(cusSet.Tables("Customer").Rows(accountIndex).Item("ExpirationDate")) < Date.Today Then

Try that, and see if it works. Could be overly simple, and perhaps you've tried it before, but it might work.

Nov 19th, 2007, 3:36 PM	#1
sackarias Programmer Join Date: Jan 2006 Posts: 58 Rep Power: 3	Problems with Date objects I'm writing a program that's interacting with a database that has two tables. The table relevant to my question is my customer table, which has a Date/Time field that expresses the current customers account expiration date. I'm having trouble comparing a customer's expiration date to another date object to verify if their account expired. This code checks if a Dvd is checked out, if it isn't, ask the user's account number. Next I check (where error keeps occuring) if the expiration date is prior to todays date, thus making it valid, but it doesn't work that way. In which ways can you go about comparing two dates? Maybe I missed a certain method pertaining to comparing dates, I saw a compareTo, nothing like an isLessThen or similar. Any help would be greatly appreciated, thanks a lot. Also, when I copied my code over it automatically put returns so it's sort of hard to read, sorry for that. (Toggle Plain Text) If dbSetAdapter.Tables("Dvds").Rows(index).Item("CheckedOutBy") = "XXXXXXX" Or 0 Then response = InputBox("Enter your account number", "Account Number") If findAccount(response, 0) <> -1 Then accountIndex = findAccount(response, 0) 'account found, put index in variable If cusSet.Tables("Customer").Rows(accountIndex).Item("ExpirationDate") < Date.Today Then 'ERROR HERE, How to compare if one date is "less then" another MessageBox.Show("not expired") End If Else MessageBox.Show("Account number does not exist") End If Else MessageBox.Show("This DVD is checked out.") End If If dbSetAdapter.Tables("Dvds").Rows(index).Item("CheckedOutBy") = "XXXXXXX" Or 0 Then response = InputBox("Enter your account number", "Account Number") If findAccount(response, 0) <> -1 Then accountIndex = findAccount(response, 0) 'account found, put index in variable If cusSet.Tables("Customer").Rows(accountIndex).Item("ExpirationDate") < Date.Today Then 'ERROR HERE, How to compare if one date is "less then" another MessageBox.Show("not expired") End If Else MessageBox.Show("Account number does not exist") End If Else MessageBox.Show("This DVD is checked out.") End If

Nov 19th, 2007, 3:58 PM	#2
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	Re: Problems with Date objects You can deal with dates in a number of different ways. If you think hard enough and work hard enough, you can even deal with them correctly. My approach is to convert evey date that is to be subjected to manipulation to a form that represents a a numerical value expressing time elapsed since some benchmark time in the past. You, too, can do this. It doesn't much matter whether you read the material pertaing to VB, or to PHP, or to C, or to a non-language entity such as an operating system. Read, understand, adapt, and write. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Jan 9th, 2008, 12:46 PM	#3
SydneyMcConnell 18 Year Old Programmer Join Date: Jan 2008 Posts: 26 Rep Power: 0	Re: Problems with Date objects Enclose cusSet.Tables("Customer").Rows(accountIndex).Item("ExpirationDate") in a CDate, and see if that solves the issue. In some cases, it may not implicitly convert an object in an equation when you're working with Data, and so it may just stay as an object. It should be like: (Toggle Plain Text) If CDate(cusSet.Tables("Customer").Rows(accountIndex).Item("ExpirationDate")) < Date.Today Then If CDate(cusSet.Tables("Customer").Rows(accountIndex).Item("ExpirationDate")) < Date.Today Then Try that, and see if it works. Could be overly simple, and perhaps you've tried it before, but it might work.

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Programming Forums > Application Development > Visual Basic .NET

Problems with Date objects