Query String Problem\VB

[George]

I am trying to check whether a query string is being passed to my .aspx page, like so:

If Not Request.QueryString Is Nothing Then
If CInt(Request.QueryString.GetValues("values")(0)) <> 1 Then
Response.Redirect("../somepage.htm")
End If
Else
Response.Redirect("../somepage.htm")
End If

If there is a query string, everything is fine, but when there isn't one, the app crashes on the
second line :

If CInt(Request.QueryString.GetValues("values")(0)) <> 1 Then

:with this error:

Exception Details: System.NullReferenceException: Object reference not set to an instance of an
object.

What I don't understand, is why is it getting passed this line anyway:

If Not Request.QueryString Is Nothing Then

:when there wasn't even a query string passed? Why didn't it jump down to the Else part, instead?

Thanks,
George

[Anatoly]

Check for Request.QueryString.ToString() = string.empty

"George" <------@----.---> wrote in message
news:Sd*******************@bgtnsc04-news.ops.worldnet.att.net...

I am trying to check whether a query string is being passed to my .aspx page, like so:
If Not Request.QueryString Is Nothing Then
If CInt(Request.QueryString.GetValues("values")(0)) <> 1 Then
Response.Redirect("../somepage.htm")
End If
Else
Response.Redirect("../somepage.htm")
End If

If there is a query string, everything is fine, but when there isn't one, the app crashes on the second line :

If CInt(Request.QueryString.GetValues("values")(0)) <> 1 Then

:with this error:

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

What I don't understand, is why is it getting passed this line anyway:

If Not Request.QueryString Is Nothing Then

:when there wasn't even a query string passed? Why didn't it jump down to the Else part, instead?
Thanks,
George

[Cezary Nolewajka]

Hi George,

The point is that the QueryString property as such is always set and never
null (nothing). It is an object of NameValueCollection type that can have
zero elements (if query string is empty) but still is instantiated.

So, instead of checking the Request.QueryString existance, you should check
if it has the elemenent (field key) you are looking for:

string[] arString;
arString = Request.QueryString.GetValues("values");

if (arString != null)
{
...
}

Sorry for the c# code, but in nicely transposes to your VB.

--
Cezary Nolewajka
mailto:c.*********************@no-sp-am-eh-mail.com
remove all "no-sp-am-eh"s to reply
"George" <------@----.---> wrote in message
news:Sd*******************@bgtnsc04-news.ops.worldnet.att.net...

I am trying to check whether a query string is being passed to my .aspx page, like so:
If Not Request.QueryString Is Nothing Then
If CInt(Request.QueryString.GetValues("values")(0)) <> 1 Then
Response.Redirect("../somepage.htm")
End If
Else
Response.Redirect("../somepage.htm")
End If

If there is a query string, everything is fine, but when there isn't one, the app crashes on the second line :

If CInt(Request.QueryString.GetValues("values")(0)) <> 1 Then

:with this error:

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

What I don't understand, is why is it getting passed this line anyway:

If Not Request.QueryString Is Nothing Then

:when there wasn't even a query string passed? Why didn't it jump down to the Else part, instead?
Thanks,
George

[George]

Anatoly,

Apparently, ToString is not available in that context. Thanks for the suggestion, though.

George

"Anatoly" <an*****@hotmail.com> wrote in message news:e1**************@TK2MSFTNGP10.phx.gbl...

Check for Request.QueryString.ToString() = string.empty

"George" <------@----.---> wrote in message
news:Sd*******************@bgtnsc04-news.ops.worldnet.att.net...

I am trying to check whether a query string is being passed to my .aspx

page, like so:

If Not Request.QueryString Is Nothing Then
If CInt(Request.QueryString.GetValues("values")(0)) <> 1 Then
Response.Redirect("../somepage.htm")
End If
Else
Response.Redirect("../somepage.htm")
End If

If there is a query string, everything is fine, but when there isn't one,

the app crashes on the

second line :

If CInt(Request.QueryString.GetValues("values")(0)) <> 1 Then

:with this error:

Exception Details: System.NullReferenceException: Object reference not set

to an instance of an

object.

What I don't understand, is why is it getting passed this line anyway:

If Not Request.QueryString Is Nothing Then

:when there wasn't even a query string passed? Why didn't it jump down to

the Else part, instead?

Thanks,
George

[George]

Cezary,

I tried what you suggested and that solved my problem! Learn something new everyday.

Thanks for your help.
George
"Cezary Nolewajka" <c.*********************@no-sp-am-eh-mail.com> wrote in message
news:%2****************@TK2MSFTNGP09.phx.gbl...

Hi George,

The point is that the QueryString property as such is always set and never
null (nothing). It is an object of NameValueCollection type that can have
zero elements (if query string is empty) but still is instantiated.

So, instead of checking the Request.QueryString existance, you should check
if it has the elemenent (field key) you are looking for:

string[] arString;
arString = Request.QueryString.GetValues("values");

if (arString != null)
{
...
}

Sorry for the c# code, but in nicely transposes to your VB.

--
Cezary Nolewajka
mailto:c.*********************@no-sp-am-eh-mail.com
remove all "no-sp-am-eh"s to reply
"George" <------@----.---> wrote in message
news:Sd*******************@bgtnsc04-news.ops.worldnet.att.net...

I am trying to check whether a query string is being passed to my .aspx

page, like so:

If Not Request.QueryString Is Nothing Then
If CInt(Request.QueryString.GetValues("values")(0)) <> 1 Then
Response.Redirect("../somepage.htm")
End If
Else
Response.Redirect("../somepage.htm")
End If

If there is a query string, everything is fine, but when there isn't one,

the app crashes on the

second line :

If CInt(Request.QueryString.GetValues("values")(0)) <> 1 Then

:with this error:

Exception Details: System.NullReferenceException: Object reference not set

to an instance of an

object.

What I don't understand, is why is it getting passed this line anyway:

If Not Request.QueryString Is Nothing Then

:when there wasn't even a query string passed? Why didn't it jump down to

the Else part, instead?

Thanks,
George