"Object reference not set to an instance of an object." after constructor fires

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Vern DeHaven <vernet.dehaven uc [.] edu> - 21 Mar 2005 17:45 GMT

Hello all,

Working on a W2K3 box with Framework version 1.1.4322 here. I've
implemented a Web service in VB.NET by generating a server skeleton off
the WSDL and overriding the abstract class. This Web service operates
correctly. To conform to standards set by our group recently, I reworked
the WSDL to reflect namespace changes and reimplemented the service in
both VB.NET and C# (as neither work now). When compared, the only
syntactic differences between the original and new VB.NET services are
namespace declarations. The other change was the last offered update to
my Framework for W2K3 SP1. In both the new services, I get the subject
error after the constructor successfully fires. No error shows in the
Debug window; I get exit codes of 0.

The original service still operates correctly after the Framework update.
In all three services (working and broken), the last line added to the
Debug window before I stop execution is the loading of a referenced
assembly not part of the Framework.

I deployed the broken C# version to a Windows 2000 Server SP4 box with
Framework version 1.1.4322 with the same result.

Anyone had similar issues?

Thanks,
Vern DeHaven

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Vern DeHaven - 23 Mar 2005 19:12 GMT

Found the issue. I had left out one very important detail: one of our new
standards is to specify names of elements in Pascal case (e.g.
ElementName). The old, working service had element names in camel case
(e.g. elementName). The wsdl.exe tool names parameters exactly the same
as their types in the generated abstract class, for example:

public abstract ReceiveBuffer
modify([System.Xml.Serialization.XmlElementAttribute(Namespace="http://myuri.com/mod")]
SendBuffer SendBuffer);

The mistake I made was that I had camel-cased the parameter name to
distinguish it as such:

public abstract ReceiveBuffer
modify([System.Xml.Serialization.XmlElementAttribute(Namespace="http://myuri.com/mod")]
SendBuffer sendBuffer);

I did this without adding the ElementName property to the
XmlElementAttribute to correct the serialization. Here's how it should
read:

public abstract ReceiveBuffer
modify([System.Xml.Serialization.XmlElementAttribute(Namespace="http://myuri.com/mod",
ElementName="SendBuffer")] SendBuffer sendBuffer);

Sorry about this post.

Vern

On Mon, 21 Mar 2005 11:45:21 -0500, Vern DeHaven <vernet.dehaven uc [.]
edu> <[@]> wrote:

> Hello all,
>
[quoted text clipped - 22 lines]
> Thanks,
> Vern DeHaven

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"Object reference not set to an instance of an object." after constructor fires

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