Checking if variable has been declared

[multiplex77]

Hi,

How can I check if a session variable (or any other variable for that matter) has been declared?

Should i use

If isNull(Session("myVar&quot)

or

If isEmpty(Session("myVar&quot)

Or is there some other better way?

Thanks for the help!

 

[FesterSXS]

If you add 'Option Explicit' to the top of your ASP code then it will generate an error if you try to use an undeclared variable. This is also useful for debugging mispelt variable names. Tony

http://www.phoenix-paints.co.uk/portfolio

 

[multiplex77]

Thanks very much for the tip. I am aware of Option Explicit, but I don't want it to generate a error. I need to catch the error before it gets generated.

This Session variable is set in an included page.

Thanks

 

[GabeC]

Are you wanting to know if a variable has never been declared or if it just hasn't been used yet? It looks like you just want to know if there is any data in a session variable. Is that correct?

Are you expecting the session variable to be text or some COM object?

Thanks,

Gabe

 

[multiplex77]

I need to know if the session variable exists. If it hasn't been declared and no data has been put into it, then it won't exist. I don't want to be calling a session variable which doesn't exist.

Thanks for the help.

 

[GabeC]

I guess what I am really trying to find out is why wouldn't you know if a session variable has been declared? You are writing the code.

Are you trying to see if specific code has been hit by the user which populates a session variable and you want to check to see what the values is?

Thanks,

Gabe

 

[FesterSXS]

Calling a non-existant Session variable wont cause any errors so you could simply check to see if the Session variable had any contents or not. If it does then use it, if it doesnt then dont.

If Session(&quot;somename&quot;) <> &quot;&quot; Then
...etc

or...

If Len(Session("somename")) > 0 Then
...etc

Tony

http://www.phoenix-paints.co.uk/portfolio

 

[multiplex77]

Thanks Tony, I guess that's what I was looking for. I thought I was getting errors from calling non-existant session variables, but I guess I was mistaken.

Thanks Gabe for your help too.