IsDate Function Problem

[TheSearcher]

I have the following code behind a command button. However, it accepts a three digit year as being valid - ex: 8/26/202. Why would this be?

'Validate Data
If IsDate(txt_DateOfIncident.Value) = False Then
MsgBox "You must enter a valid date.", vbCritical, "INVALID DATE"
txt_DateOfIncident = ""
txt_DateOfIncident.SetFocus
Exit Sub
End If

Thanks,
TS

 

[plog]

Because August 26th 202 is an actual date.

You might have to add more criteria to your test--occurs after year 2000, before year 3000 etc.

 

[MajP]

Something like this maybe

Public Function IsDateInRange(TheDate As Variant, Optional StartRange As Date, Optional EndRange As Date, Optional RangeLengthInYears As Long = 100) As Boolean
  If IsDate(TheDate) Then
    If StartRange = 0 Then StartRange = Date - RangeLengthInYears * 365
    If EndRange = 0 Then EndRange = Date + RangeLengthInYears * 365
    If TheDate >= StartRange And TheDate <= EndRange Then IsDateInRange = True
  End If
End Function


Public Sub test()
 Debug.Print IsDateInRange(#1/1/1922#) ' within 100
 Debug.Print IsDateInRange(#1/1/1900#) 'outside 100 years
 Debug.Print IsDateInRange(#1/1/1900#, , , 200) ' inside of 200 years
 Debug.Print IsDateInRange("cat") ' not a date
 Debug.Print IsDateInRange(#1/1/2020#, #1/1/2019#, #1/1/2021#)
 Debug.Print IsDateInRange(#1/2/2021#, #1/1/2019#, #1/1/2021#)
End Sub

 

[TheSearcher]

Because August 26th 202 is an actual date.

You might have to add more criteria to your test--occurs after year 2000, before year 3000 etc.

You're absolutely right. Thanks Plog! I'm going to take a break now.

 

[Pat Hartman]

Don't forget the rum for your coffee

 

[arnelgp]

IsDate() function does not test for a Valid date.
what it does is determine if the supplied Expression can be
evaluated to a date.

you must Explicitly inform the user (through a label, perhaps) what
is the Valid date format to enter into the Textbox, eg:

label1.caption = "Enter Date (dd/mm/yyyy):

you will then need to Validate the entry:
1. the length = 10
2. first 2 (dd) digit must not exceed 31.
3. the (mm) must be between 1 and 12.
4. yyyy must be between 2000 and 2099.
5. the "/" placing should be correct

 

[onur_can]

When the IsDate function sees any expression that can be converted to a date, it returns True. In your example, August 26th 202 would perceive as a valid date. Because your operating system considers the dates between January 1, 100 and December 31, 9999 valid. For example;
IsDate ("October 12, 1998") Returns True.
IsDate ("10/12/98") Returns True.
IsDate ("onur") Returns False.

What value do you think IsDate (# 1/1 #) returns? Maybe most of you will say False but wrong answer.
This expression returns True. You ask why ? Because an expression with Month and Day can be automatically converted to date. Accepts the current year for the year. So
It happens 1/1/2020.

In this case, you need to give more specific expressions to the IsDate function. Mr. arnelgp's method would be a suitable solution.

 

[MajP]

The solution I provided validates any date between a given range or range length. I already provided the solution.

 

[onur_can]

Yes, you are right, Mr. MajP, when I examined it, you provided the solution.

 

[Isaac]

A very simple approach is to first test if IsDate, and then test year.

If IsDate(value) then
    if Year(Value)<1950 then 'whatever year value you want
        'something is wrong
    end if
end if

 

[plog]

Wow, we really need an 'Outdo One Another Simple Coding Challenge Of The Week' contest on this forum.

Next weeks problem:

Find the sum of all prime numbers between 1-10

 

[Isaac]

Wow, we really need an 'Outdo One Another Simple Coding Challenge Of The Week' contest on this forum

Simplicity is certainly the ideal

 

[onur_can]

What do you mean by simplicity? Many people in a community have different ideas, you take these ideas and simplify them, not the environment!