On Jan 31, 10:11 am, dj11235...@gmail.com wrote:
> Hello
>
> I'm working on a product that is using XmlLite.  Following the example
> given by Microsoft on their website (http://msdn2.microsoft.com/en-us/
> library/ms753116(VS.85).aspx) I have made a while loop that calls
> IXmlReader::Read() and switches on the nodeType gotten.  In the
> example, they use IXmlReader::IsEmptyElement() to determine if a node
> looks like this:
>
> <nodeName attributeName="attributeValue" />
>
> As I am walking through a hierarchical XML, I need to know when a node
> ends.  So I have both that call to IXmlReader::IsEmptyElement() and
> code in the case for XmlNodeType_EndElement that walks me back up to
> the parent.
>
> Unfortunately, I am not seeing IXmlReader::IsEmptyElement() returning
> true ever.  The node it is reading in my testing is this:
>
>           <parameterType name="stringParameter" type="string"
> multiValued="false" />
>
> And the code reading that node is effectively this:
>
>         while(S_OK == (hr = xmlReader->Read(&nodeType)))
>         {
>                 switch(nodeType)
>                 {
>                 case XmlNodeType_Element:
>                         {
>                                 if(FAILED(hr = xmlReader->GetLocalName(&nodeName, NULL)))
>                                         // ... error handling
>
>                                 // ... do stuff with the node
>
>                                 while(true)
>                                 {
>                                         if(FAILED(hr = reader->MoveToNextAttribute()))
>                                                 // ... error handling
>
>                                         if(S_FALSE == hr)
>                                                 break;
>
>                                         if(FAILED(hr = reader->GetLocalName(&attributeName, NULL)))
>                                                 // ... error handling
>
>                                         if(FAILED(hr = reader->GetValue(&attributeValue, NULL)))
>                                                 // ... error handling
>
>                                         // ... do stuff with the attribute
>                                 }
>
>                                 // ... I never see this return true, even on the node example
> above
>                                 if(! xmlReader->IsEmptyElement())
>                                         // ... walk down the hierarchical tree of data
>
>                                 // ... note that I expect to stay put (not walk down) if the
> element is empty
>                         }
>                         break;
>                 case XmlNodeType_EndElement:
>                         {
>                                 // ... walk up the hierarchical tree of data
>                         }
>                         break;
>
>                 // ...
>
> If anyone has used IXmlReader::IsEmptyElement successfully, can you
> please tell me what you did to make it work?  Or, if anyone else has
> encountered the same problem, I would be encouraged to hear that,
> because then I wouldn't feel so bad kludging the hierarchical logic.

Hi again

I have discovered the problem.  The IXmlReader loses its state about
the element once you go read stuff about the attributes.  The example
code provided by Microsoft (http://msdn2.microsoft.com/en-us/library/
ms753116(VS.85).aspx) is incorrect.  You need to check
IsEmptyElement() before doing any work with the attributes.  I am
posting this to hopefully help anyone who comes along with the same
problem later on.  I now have this, and it works fine:

	while(S_OK == (hr = xmlReader->Read(&nodeType)))
	{
		switch(nodeType)
		{
		case XmlNodeType_Element:
			{
				// ******************** new boolean to save the state
				isEmptyElement = xmlReader->IsEmptyElement();

				if(FAILED(hr = xmlReader->GetLocalName(&nodeName, NULL)))
					// ... error handling

				// ... do stuff with the node

				while(true)
				{
					if(FAILED(hr = reader->MoveToNextAttribute()))
						// ... error handling

					if(S_FALSE == hr)
						break;

					if(FAILED(hr = reader->GetLocalName(&localAttributeName, NULL)))
						// ... error handling

					if(FAILED(hr = reader->GetValue(&value, NULL)))
						// ... error handling

					// ... do stuff with the attribute
				}

				// ******************** check my saved state rather than asking
the reader
				if(! isEmptyElement)
					// ... walk down the heirarchical tree of data

				// ... note that I expect to stay put (not walk down) if the
element is empty
			}
			break;
		case XmlNodeType_EndElement:
			{
				// ... walk up the hierarchical tree of data
			}
			break;

		// ...

I find this behavior tremendously annoying, but at least I was able to
get things working.