Hi,
I'll try to point you some more info:
First consider these functions in VBS/VB
CInt - short integer (2 bytes signed integer) - VT_I2
Clng - Long integere (4 bytes signed integer) - VT_I4
CCur - Currency (8 bytes signed integer in fact, but shown as currency in
practice) - VT_CY
CSng - 4 byte floating point - VT_R4
CDbl - 8 bytes floating point - VT_R8
The VT_XX constants are the type constants for the so called VARIANT type in
automation
Win32 COM APIs. It supports more types and many of them are directly
supported by VBS
See the VarType function and the corresponding constants - they are
numerically equivalent
to these VT_X constants (only the names are different). In other words VBS
keeps everything
in VARIANT - any variable can hold any kind of value supported by VARIANTs
but you have
ability (through the above functions - not all are listed here) to specify
the contents of the variant.
Most ActiveX will convert the input parameters (and read properties) to the
type they need, but
if they know what they need! Many ActiveX are able to work with different
values and produce
different results. One example you meet every day are the collections - if
you put numeric index
this is the index of an item, if you put a string this is the name of the
item. Therefore the strict
conversion is useful (if you have time to deal with these details) always.
Checking functions:
IsNumeric - will return true if the passed parameter is a variant of numeric
type or can be converted to
a numeric type - see this:
v = "1"
IsNumeric will return True
v = 1
IsNumeric will return True
While VarType will return vbString in the first case and vbInteger in the
second.
Thus you can check if the conversion is possible with IsNumeric and "what I
have currently" with
VarType. Of course in ASP you will have mostly string to numeric and reverse
conversions, but
using 3-D party components may lead to something else.
ADO
You have a Filed.Type property but it returns ADO specific constants, not
very convenient. In many
cases you can do something better if you need to check what is the type of a
field. Check the type of the
field value - like this:
VarType(rst("field").Value)
The .Value is important - if omited you will always receive vbObject - e.g.
the ADO field is object and Value is its
default property implicitly resolved in most cases. I understood you do not
have this problem right now but
if you need to learn about the recordset's values dynamically and you want
to avoid using ADO specific constants
and methods this will help in many cases.
My own suggestion:
rst("FieldName").Value = variable
variable = rst("FieldName").Value
Most people prefer to write:
rst("FieldName") = variable
variable = rst("FieldName")
Why? First gets the variable value the second records a reference to the
Field object. In the first case
variable will be valid always in the second it will depend on the recordset
and if it is closed you will not
be able to read the value. This is similar to the GetRows - it copies the
values from teh recordset - i.e.
independent copy, the recordset can be closed.
Why I am talking about this? Because I want of course ;) heh , but also
because I am working with
many external components - mine, others .... And with them this could be
very important - passing
a reference to an ADO Field to another object may be inconenient and
sometimes dangerous. In your
case you want to get a variable from the Request - suppose this:
rst("f") = Request("V")
This line depends on resulution of the default properties and is equal to:
rst.Field("f").Value = Request.Item("v").Item()
ADO bahaves this way, but who knows what is the bahavior of some 3-Dparty
component ?
Then:
obj.property = CLng(Request("V"))
will guarantee you are passing a long integer to the component's property.
And so on ...
Excuse me for the long story but I just corrected one's ASP causing these
problems :)
Michael
-----Original Message-----
From: Andy Hayman [mailto:[EMAIL PROTECTED]]
Sent: Friday, August 09, 2002 7:05 PM
To: ActiveServerPages
Subject: Turning a string to an number
I did know but I cant find it, how do you turn a string into a number
Basicly I have a number in a drop down box which is being treated as a
Number but I need to put it in a numberic field!!!
---
Andy Hayman
Kensington Computers
Internet & Computers Systems Consultant
Web <http://www.ken.co.uk>
Email <mailto:[EMAIL PROTECTED]>
Telephone 020 7835 1282
Fax: 020 7373 6900
Disclaimer
This e-mail is confidential and intended solely for the use of the
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