InvalidOperationException: ReadElementContentAsString method is not supported on node type None

[J055]

Hi

I get the error:
System.InvalidOperationException: The ReadElementContentAsString method is
not supported on node type None. Line 267, position 12.

when running the following code:

while (reader.Read())
{
// Move to the Email element.
reader.ReadToFollowing("Email");
string email = reader.ReadElementContentAsString();

Trace.Write("email " + email);
}

Line 267, position 12. is the end of the file, i.e. after the closing root
element tag. The code works fine up until that point, it writes out the
correct values in the trace. The problem occurs with other
ReadElementContentAs... methods too.

How do I sort this out?

Thanks
Andrew

[WenYuan Wang [MSFT]]

Hi Andrew,

This error means Reader.ReadToFollowing("Email") cannot find the correct
element. Reader will stop at the end of your file. For this reason,
ReadElementContentAsString will throw System.InvalidOperationException: The
ReadElementContentAsString method is not supported on node type None.

Have you checked whether there an element named "Email" in your XML file?
Be careful of the case sensitive.

Additionally, ReadToFollowing() method will return a bool value. If this
method has located the element, it will be true, otherwise, it will be
false.
I recommend you may make some change in your code to narrow-down the issue.

while (reader.Read())
{
// Move to the Email element.
bool flag= reader.ReadToFollowing("Email");
if (flag)
{
string email = reader.ReadElementContentAsString();
.......
}
......

Hope this helps.Please let me know if you have any further issue on this.
I'm glad to assist you.
Have a great day,
Sincerely,
Wen Yuan
Microsoft Online Community Support
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[J055]

Hi Wen Yuan

Thanks for your help so far. Testing that ReadToFollowing is true first
works for me. Can you help with working out the best approach and classes to
use for the following?

I want to import a user uploaded XML file into a database. The user uses a
web form to upload the file. The file should conform to a defined schema but
it may contain errors so we want to alert the user before proceeding to
insert the data into the database. I would like to do the following:

1. xml file is uploaded using the FileUpload control, e.g.

XmlReaderSettings readerSettings = new XmlReaderSettings();
//validation flags
readerSettings.ValidationFlags =
XmlSchemaValidationFlags.ReportValidationWarnings;
readerSettings.ValidationType = ValidationType.Schema;
readerSettings.Schemas = sc;
readerSettings.ValidationEventHandler += new
ValidationEventHandler(ValidationCallBack);
reader = XmlReader.Create(fileUpload.FileContent, readerSettings);

2. now I have an XmlReader object with a schema so I check for validation.
As the XmlReader is a forward only reader I have to store any valid values
at the same time as checking the document for validation. This seems a
little messy.
Can I use the XmlSerializer.Deserialize method and the Validator at the same
time? The xml document looks like this:

<Accounts>
<Account ID="1003" Code="code1">
<Email>[e-mail]</Email>
<FirstName>f1</FirstName>
<LastName>l1</LastName>
<AccountType>3</AccountType>
<IsActive>true</IsActive>
</Account>
<Account ID="1004" Code="code2">
<Email>[e-mail]</Email>
<FirstName>f2</FirstName>
<LastName>l2</LastName>
<AccountType>1</AccountType>
<IsActive>true</IsActive>
</Account>
</Accounts>

I need to loop through each Account node and call a business object method
to insert into a database if the values validate with the schema. I've
looked at the documentation but I can't find a clear way to do this. Also I
don't understand how the Deserialize interprets the fact that some
information is held in attributes rather than elements. Does it get this
information from the schema?

If I can use the Deserialize method do I create a collection of custom
objects and then loop though these and call my insert method? How would I do
this?

I hope I'm being clear here. I think my requirements are quite simple but I
am unsure on which classes are appropriate and how to use them for my
application.

Thanks in advance for you help.
Andrew

[John Saunders [MVP]]

"J055" <j0**@newsgroups.nospamwrote in message
news:uM****************@TK2MSFTNGP04.phx.gbl...

Hi Wen Yuan

Thanks for your help so far. Testing that ReadToFollowing is true first
works for me. Can you help with working out the best approach and classes
to use for the following?

I want to import a user uploaded XML file into a database. The user uses a
web form to upload the file. The file should conform to a defined schema
but it may contain errors so we want to alert the user before proceeding
to insert the data into the database. I would like to do the following:

1. xml file is uploaded using the FileUpload control, e.g.

XmlReaderSettings readerSettings = new XmlReaderSettings();
//validation flags
readerSettings.ValidationFlags =
XmlSchemaValidationFlags.ReportValidationWarnings;
readerSettings.ValidationType = ValidationType.Schema;
readerSettings.Schemas = sc;
readerSettings.ValidationEventHandler += new
ValidationEventHandler(ValidationCallBack);
reader = XmlReader.Create(fileUpload.FileContent, readerSettings);

2. now I have an XmlReader object with a schema so I check for validation.
As the XmlReader is a forward only reader I have to store any valid values
at the same time as checking the document for validation. This seems a
little messy.
Can I use the XmlSerializer.Deserialize method and the Validator at the
same time? The xml document looks like this:

<Accounts>
<Account ID="1003" Code="code1">
<Email>[e-mail]</Email>
<FirstName>f1</FirstName>
<LastName>l1</LastName>
<AccountType>3</AccountType>
<IsActive>true</IsActive>
</Account>
<Account ID="1004" Code="code2">
<Email>[e-mail]</Email>
<FirstName>f2</FirstName>
<LastName>l2</LastName>
<AccountType>1</AccountType>
<IsActive>true</IsActive>
</Account>
</Accounts>

I need to loop through each Account node and call a business object method
to insert into a database if the values validate with the schema. I've
looked at the documentation but I can't find a clear way to do this. Also
I don't understand how the Deserialize interprets the fact that some
information is held in attributes rather than elements. Does it get this
information from the schema?

If the XML document isn't "too large", then you can load it into an
XmlDocument and then use whatever method you like to reference the data in
the XmlDocument:

XmlDocument doc = new XmlDocument();
doc.Schemas = sc;
using (XmlReader reader = XmlReader.Create(fileUpload.FileContent,
readerSettings)) // Implements IDisposable in 2.0
{
doc.Load(reader);
}

I believe that, in this case, the nodes in the XmlDocument will be decorated
with information from the schema (the Post Schema Validation Infoset or
PSVI). I haven't used this much, but have seen evidence of this in the
debugger.

You may also want to try an XmlDataDocument if a DataSet would be of use to
you.
Good luck.
--

John Saunders [MVP]

[WenYuan Wang [MSFT]]

Hi Andrew,
Thanks for John's suggestion.

>If I can use the Deserialize method do I create a collection of custom

objects and then loop >though these and call my insert method? How would I
do this?

About how to use XmlSerializer mthod, you should have to create a new class
according to your XML schema. For some information is held in attributes
rather than elements, you should have to use attribute in your class.

For example:
http://www.codeproject.com/soap/GameCatalog.asp
[Using the XmlSerializer Attributes]

However, I'm afraid this is not the best approach/Class for you to achieve
what you need. There will be a lot of hard work you have to do. In general,
XmlSerializer method is used for Web service and .net Remoting.
In short, I agree John, XMLDocument is a simple way you can consider of.

XmlDocument doc = new XmlDocument();
....
doc.Load(reader);
//doc.load() method will loop through the xmlreader, if the xml file
doesn't conform to the defined schema. The ValidationEvent will fire. You
can also traverse each element/attribue by doc object.

http://www.codeproject.com/soap/myXPath.asp
[Manipulate XML data with XPath and XmlDocument (C#)]

Hope this helps.
Sincerely,
Wen Yuan
Microsoft Online Community Support