Please clarify how null nodeset result processes?

Hi, I continue to have trouble with this. Using the following xml
sample:

<Station name="Station1" line_stop="yes"/
OR when NO line_stop attribute exists.

In asp.net page, I use xpath to determine IF the line_stop attribute
exists (or am TRYING to!)

Dim xDoc as XmlDocument
Dim xNode As XmlElement =
xDoc.SelectSingleNode("//Station[@dotnet.itags.org.name='Station1'][@dotnet.itags.org.line_stop='yes']")

If Not xNode.Value Is Nothing Then
If xNode.Value = "yes" Then
do this...
End If
End If

If there is no line_stop attribute, I get an error for "Object reference
not set to an instance of an object" at the If Not xNode.Value
line...obviously returning no node.

Please tell me where I'm going wrong.

Thanks,
Kathy

*** Sent via Developersdex http://www.developersdex.com ***
Don't just participate in USENET...get rewarded for it!Kathy, you might get better responses in the .framework group, since this
doesn't seem to be specific to ASP.NET.

--
John Saunders
Internet Engineer
john.saunders@.surfcontrol.com

"Kathy Burke" <kathyburke40@.attbi.com> wrote in message
news:%23xJL5a0aDHA.2412@.TK2MSFTNGP10.phx.gbl...
> Hi, I continue to have trouble with this. Using the following xml
> sample:
> <Station name="Station1" line_stop="yes"/>
> OR when NO line_stop attribute exists.
> In asp.net page, I use xpath to determine IF the line_stop attribute
> exists (or am TRYING to!)
> Dim xDoc as XmlDocument
> Dim xNode As XmlElement =
> xDoc.SelectSingleNode("//Station[@.name='Station1'][@.line_stop='yes']")
> If Not xNode.Value Is Nothing Then
> If xNode.Value = "yes" Then
> do this...
> End If
> End If
> If there is no line_stop attribute, I get an error for "Object reference
> not set to an instance of an object" at the If Not xNode.Value
> line...obviously returning no node.
> Please tell me where I'm going wrong.
> Thanks,
> Kathy
> *** Sent via Developersdex http://www.developersdex.com ***
> Don't just participate in USENET...get rewarded for it!
check if the xNode is nothing first

"Kathy Burke" <kathyburke40@.attbi.com> wrote in message
news:%23xJL5a0aDHA.2412@.TK2MSFTNGP10.phx.gbl...
> Hi, I continue to have trouble with this. Using the following xml
> sample:
> <Station name="Station1" line_stop="yes"/>
> OR when NO line_stop attribute exists.
> In asp.net page, I use xpath to determine IF the line_stop attribute
> exists (or am TRYING to!)
> Dim xDoc as XmlDocument
> Dim xNode As XmlElement =
> xDoc.SelectSingleNode("//Station[@.name='Station1'][@.line_stop='yes']")
> If Not xNode.Value Is Nothing Then
> If xNode.Value = "yes" Then
> do this...
> End If
> End If
> If there is no line_stop attribute, I get an error for "Object reference
> not set to an instance of an object" at the If Not xNode.Value
> line...obviously returning no node.
> Please tell me where I'm going wrong.
> Thanks,
> Kathy
> *** Sent via Developersdex http://www.developersdex.com ***
> Don't just participate in USENET...get rewarded for it!
Doesn't "If Not xNode.Value Is Nothing Then" check that xNode is
nothing?

Thanks.

Kathy

*** Sent via Developersdex http://www.developersdex.com ***
Don't just participate in USENET...get rewarded for it!
"Kathy Burke" <kathyburke40@.attbi.com> wrote in message
news:ei17Bx0aDHA.2024@.TK2MSFTNGP12.phx.gbl...
> Doesn't "If Not xNode.Value Is Nothing Then" check that xNode is
> nothing?

No. That checks to see if xNode.Value is Nothing. If xNode is Nothing, the
above "If" statement will throw a NullReferenceException.

To see if xNode is Nothing try:

If Not xNode is Nothing Then

--
John Saunders
Internet Engineer
john.saunders@.surfcontrol.com
Hi again,

I've tried adding:

If Not n16 Is Nothing Then
If n16.Value = "yes" Then
Dim strNext As String = "yes"
End If
End If

but still get a NullReferenceException on the first line of the above
snippet. In this particular case, I SHOULD get "nothing" as a result
since the attribute 'line_stop' doesn't exist for the element
selected...but the code should then continue, yes?

Any suggestions for how I can proceed?

Kathy

*** Sent via Developersdex http://www.developersdex.com ***
Don't just participate in USENET...get rewarded for it!

Please explain Delegates

Can someone pls explain the concept of delegates in laymans terms. Code samples in VB will be most helpful as I am having a lot of trouble understanding this subject.Delegates are objects with one the most important method. You may think of it by namecall();

if you wnat a method of one object to be called by third object. you give to this third object delegate to the method of the first object.
Hi,

Delegates are like function pointers in C++. They are used to pass the functions as parameter to the other function. There are so many articles on this topic. please visit
http://www.csharpfriends.com/Articles/getArticle.aspx?articleID=141

Thanks,
Sridhar!!

Please help - how to create a Printer Friendly web page...

Dear Experts,
I've got a trouble problem that I need your help. The scenario is the
following:

1) I need to add a "Print" button to my web page;
2) by clicking this button, the web page should be able to print out a
well-formatted web page (printer friendly ). That means, I need to adjust the
printing margins (left, top, right, bottom) programmatically.

I really have no idea on how to achieve this but I know this is a very
typical scenario. Could you please give me some advices? Please help.

Thanks a lot.
TiggerAs long as the targetted browser is IE >= 5 you can use the onbeforeprint
and on afterprint events in javascript
(I found this out yeterday)
I wrote the code below to hide a print button and decrease the width when
the document is printed
Hope this helps,
mortb

<head>
<script language="javascript">
var originalWidth;
function window.onbeforeprint()
{
originalWidth = document.getElementById('_tblResult').style.width;
document.getElementById('_tblResult').style.width = '625px';
document.getElementById('_btnPrint').style.display = 'none';
}
function window.onafterprint()
{
document.getElementById('_tblResult').style.width = originalWidth;
document.getElementById('_btnPrint').style.display = 'inline';
}
</script>
</HEAD
"Tigger" <Tigger@.discussions.microsoft.com> wrote in message
news:C2D9F1F1-954D-448A-A201-BAAA332C866E@.microsoft.com...
> Dear Experts,
> I've got a trouble problem that I need your help. The scenario is the
> following:
> 1) I need to add a "Print" button to my web page;
> 2) by clicking this button, the web page should be able to print out a
> well-formatted web page (printer friendly ). That means, I need to adjust
> the
> printing margins (left, top, right, bottom) programmatically.
> I really have no idea on how to achieve this but I know this is a very
> typical scenario. Could you please give me some advices? Please help.
> Thanks a lot.
> Tigger
>
Use a media-specific print stylesheet.
For example, try slapping this in a file called print.css
@.page { 0.75in; }
And putting this line in your HTML
<link rel="stylesheet" type="text/css" href="http://links.10026.com/?link=print.css" media="print"
At this point, you should be able to print from your browser normally. If
you need to initiate printing from a button, you should be able to do
something like this:
<input type="button" value="Print me!" onclick="window.print()"
This article might give you some ideas on other things you can do with this
techinque: http://www.alistapart.com/articles/goingtoprint/
And there's always the CSS reference: http://www.w3.org/TR/CSS21/

"Tigger" wrote:

> Dear Experts,
> I've got a trouble problem that I need your help. The scenario is the
> following:
> 1) I need to add a "Print" button to my web page;
> 2) by clicking this button, the web page should be able to print out a
> well-formatted web page (printer friendly ). That means, I need to adjust the
> printing margins (left, top, right, bottom) programmatically.
> I really have no idea on how to achieve this but I know this is a very
> typical scenario. Could you please give me some advices? Please help.
> Thanks a lot.
> Tigger
>
>

Please help - how to create a Printer Friendly web page...

Dear Experts,
I've got a trouble problem that I need your help. The scenario is the
following:
1) I need to add a "Print" button to my web page;
2) by clicking this button, the web page should be able to print out a
well-formatted web page (printer friendly ). That means, I need to adjust th
e
printing margins (left, top, right, bottom) programmatically.
I really have no idea on how to achieve this but I know this is a very
typical scenario. Could you please give me some advices? Please help.
Thanks a lot.
TiggerAs long as the targetted browser is IE >= 5 you can use the onbeforeprint
and on afterprint events in javascript
(I found this out yeterday)
I wrote the code below to hide a print button and decrease the width when
the document is printed
Hope this helps,
mortb
<head>
<script language="javascript">
var originalWidth;
function window.onbeforeprint()
{
originalWidth = document.getElementById('_tblResult').style.width;
document.getElementById('_tblResult').style.width = '625px';
document.getElementById('_btnPrint').style.display = 'none';
}
function window.onafterprint()
{
document.getElementById('_tblResult').style.width = originalWidth;
document.getElementById('_btnPrint').style.display = 'inline';
}
</script>
</HEAD>
"Tigger" <Tigger@.discussions.microsoft.com> wrote in message
news:C2D9F1F1-954D-448A-A201-BAAA332C866E@.microsoft.com...
> Dear Experts,
> I've got a trouble problem that I need your help. The scenario is the
> following:
> 1) I need to add a "Print" button to my web page;
> 2) by clicking this button, the web page should be able to print out a
> well-formatted web page (printer friendly ). That means, I need to adjust
> the
> printing margins (left, top, right, bottom) programmatically.
> I really have no idea on how to achieve this but I know this is a very
> typical scenario. Could you please give me some advices? Please help.
> Thanks a lot.
> Tigger
>
>
Use a media-specific print stylesheet.
For example, try slapping this in a file called print.css
@.page { 0.75in; }
And putting this line in your HTML
<link rel="stylesheet" type="text/css" href="http://links.10026.com/?link=print.css" media="print">
At this point, you should be able to print from your browser normally. If
you need to initiate printing from a button, you should be able to do
something like this:
<input type="button" value="Print me!" onclick="window.print()">
This article might give you some ideas on other things you can do with this
techinque: http://www.alistapart.com/articles/goingtoprint/
And there's always the CSS reference: http://www.w3.org/TR/CSS21/
"Tigger" wrote:

> Dear Experts,
> I've got a trouble problem that I need your help. The scenario is the
> following:
> 1) I need to add a "Print" button to my web page;
> 2) by clicking this button, the web page should be able to print out a
> well-formatted web page (printer friendly ). That means, I need to adjust
the
> printing margins (left, top, right, bottom) programmatically.
> I really have no idea on how to achieve this but I know this is a very
> typical scenario. Could you please give me some advices? Please help.
> Thanks a lot.
> Tigger
>
>