CODEWITHSUNDEEP
asp-classicvbscript
Steve Weaver
Steve Weaver

Reputation: 350

How to use DATEADD function with variables?

In classic ASP, I am unable to use DateAdd() with variables. I see no reason why this should work.

strTargetDate=DateAdd("d",visitDate,followDate)

visitDate is an incremental value -- 30, 60, 90, 180 etc. followDate is an actual date. However, I receive a type mismatch error using this code. Shouldn't this work??

Upvotes: 0

Views: 2089

Answers (1)

Ekkehard.Horner
Ekkehard.Horner

Reputation: 38745

Either visitDate isn't/can't be converted to a number, or followDate isn't/can't be converted to a date. So check the TypeName() of your input and pay attention to date formats.

Partly to show facts against @Ken's speculations:

>> s = "string"
>> WScript.Echo 0, s, TypeName(s)
>> s = DateAdd("d", 1, Now)
>> WScript.Echo 1, s, TypeName(s)
>> s = DateAdd("d", "1", CStr(now))
>> WScript.Echo 2, s, TypeName(s)
>> s = DateAdd("d", 1, "20/10/2013")
>>
0 string String
1 24.10.2013 17:05:54 Date
2 24.10.2013 17:05:54 Date
>> s = DateAdd("d", 1, "32.13.1")
>>
Error Number:       13
Error Description:  Type mismatch

Update wrt comment:

As computations involving Null should propagate Null, this

>> WScript.Echo TypeName(DateAdd("d", 1, Null))
>>
Null
>>

is no surprise. While you should handle Nulls for your DateAdd() in a way appropriate to your application, they are not the cause for the type mismatch.

Empty strings (""), however, could well be the culprits:

>> WScript.Echo TypeName(DateAdd("d", 1, ""))
>>
Error Number:       13
Error Description:  Type mismatch
>>

Upvotes: 2

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