XPathNavigator.ValueAsBoolean - no exception

[David Thielen]

Hi;

How can I tell if I can call XPathNavigator.ValueAsBoolean safely - without
throwing an exception. I want to take one course of action if the value can
be interpreted as a boolean.

But I din't want to do it using try/catch - I think having exceptions be
thrown when the code is operating normally is very bad - both from a
performance point of view and because it signifiys an error.

--
thanks - dave

[Jeffrey Tan[MSFT]]

Hi dave,

Currently we are looking for someone to help you on this issue, we will
reply to you ASAP. Thanks for your understanding.

Best regards,
Jeffrey Tan
Microsoft Online Partner Support
Get Secure! - www.microsoft.com/security
This posting is provided "as is" with no warranties and confers no rights.

[Oleg Tkachenko [MVP]]

David Thielen wrote:

How can I tell if I can call XPathNavigator.ValueAsBoolean safely - without
throwing an exception. I want to take one course of action if the value can
be interpreted as a boolean.

But I din't want to do it using try/catch - I think having exceptions be
thrown when the code is operating normally is very bad - both from a
performance point of view and because it signifiys an error.

I don't think XPathNavigator provides such functionality. The idea is
that when using ValueAsXXX methods you can be sure about node type, e.g.
because XML is valid.
As a workaround you can use Boolean.TryParse method, which doesn't throw
an exception when values cannot be converted to boolean:

if (Boolean.TryParse(navigator.Value, out myvalue))
//parsed ok
else
//not boolean value

--
Oleg Tkachenko [XML MVP, MCAD]
http://www.xmllab.net
http://blog.tkachenko.com

[David Thielen]

Hello;

My problem is customers can throw any xml at us and we have an if (Value is
Boolean) piece of logic. I think your solution will fix it - will post back
either way.

--
thanks - dave
"Oleg Tkachenko [MVP]" wrote:

David Thielen wrote:

How can I tell if I can call XPathNavigator.ValueAsBoolean safely - without
throwing an exception. I want to take one course of action if the value can
be interpreted as a boolean.

But I din't want to do it using try/catch - I think having exceptions be
thrown when the code is operating normally is very bad - both from a
performance point of view and because it signifiys an error.

I don't think XPathNavigator provides such functionality. The idea is
that when using ValueAsXXX methods you can be sure about node type, e.g.
because XML is valid.
As a workaround you can use Boolean.TryParse method, which doesn't throw
an exception when values cannot be converted to boolean:

if (Boolean.TryParse(navigator.Value, out myvalue))
//parsed ok
else
//not boolean value

--
Oleg Tkachenko [XML MVP, MCAD]
http://www.xmllab.net
http://blog.tkachenko.com

[David Thielen]

:(

I am in J# and I can't call TryParse - I assume because java does not
support ref parameters.

--
thanks - dave
"Oleg Tkachenko [MVP]" wrote:

David Thielen wrote:

How can I tell if I can call XPathNavigator.ValueAsBoolean safely - without
throwing an exception. I want to take one course of action if the value can
be interpreted as a boolean.

But I din't want to do it using try/catch - I think having exceptions be
thrown when the code is operating normally is very bad - both from a
performance point of view and because it signifiys an error.

I don't think XPathNavigator provides such functionality. The idea is
that when using ValueAsXXX methods you can be sure about node type, e.g.
because XML is valid.
As a workaround you can use Boolean.TryParse method, which doesn't throw
an exception when values cannot be converted to boolean:

if (Boolean.TryParse(navigator.Value, out myvalue))
//parsed ok
else
//not boolean value

--
Oleg Tkachenko [XML MVP, MCAD]
http://www.xmllab.net
http://blog.tkachenko.com

[Kevin Yu [MSFT]]

TryParse method is only available in .NET framework 2.0. Besides, there is
no way to judge whether a value is boolean without try to parse it and gets
exception.

http://msdn2.microsoft.com/en-us/library/khxs34ek

Kevin Yu
=======
"This posting is provided "AS IS" with no warranties, and confers no
rights."

[David Thielen]

That's what I was afraid of.

--
thanks - dave
"Kevin Yu [MSFT]" wrote:

TryParse method is only available in .NET framework 2.0. Besides, there is
no way to judge whether a value is boolean without try to parse it and gets
exception.

http://msdn2.microsoft.com/en-us/library/khxs34ek

Kevin Yu
=======
"This posting is provided "AS IS" with no warranties, and confers no
rights."