dotnet xml: Parsing XML Schema (C#) -- dotnet xml

Parsing XML Schema (C#)

Mike
6/15/2005 2:20:14 PM

dotnet xml: Hi! I have an Excel 2003 Schema I need to parse to extract elements names.
I am puzzled with the System.Xml.Schema object. Here's the example of my
schema:

I need to get a collection of element names(TemplateB62,TemplateC62 ......)

<?xml version='1.0' encoding='UTF-8'?>
<xsd:schema targetNamespace="http://tempuri.org/XMLSchema.xsd"
elementFormDefault="qualified" xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns="http://tempuri.org/XMLSchema.xsd">
<xsd:annotation>XSD Schema generated with Excel XML Toolbox</xsd:annotation>
<xsd:element name="Root" type="RootType"/>
<xsd:complexType name="RootType">
<xsd:all>
<xsd:element name="TemplateB62" type="xsd:string" minOccurs="0"
nillable="true" form="qualified"/>
<xsd:element name="TemplateC62" type="xsd:string" minOccurs="0"
nillable="true" form="qualified"/>
<xsd:element name="TemplateD62" type="xsd:string" minOccurs="0"
nillable="true" form="qualified"/>
<xsd:element name="TemplateE62" type="xsd:string" minOccurs="0"
nillable="true" form="qualified"/>
</xsd:all>
</xsd:complexType>
</xsd:schema>

For some reason, I can only get the top element.
At this URL
(http://www.xml.com/cs/user/view/cs_msg/1036?page=last&x-order=date) I found
a code snippet that's suppossed to help me drill down into children nodes,
but it bombs on this line (Invalid cast)
XmlSchemaSequence seq = (XmlSchemaSequence)ct.ContentTypeParticle;

Here's the code snippet:
XmlSchema myXmlSchema = XmlSchema.Read(new XmlTextReader(xsd),new
ValidationEventHandler(ShowCompileError));
myXmlSchema.Compile(new ValidationEventHandler(ShowCompileError));

if(myXmlSchema.IsCompiled)
{
foreach (XmlSchemaElement parentElement in myXmlSchema.Elements.Values)
{

XmlSchemaComplexType ct = parentElement.ElementType as
XmlSchemaComplexType; //Casting to complex type
if (ct != null)
{
XmlSchemaSequence seq =
(XmlSchemaSequence)ct.ContentTypeParticle; //Assuming itâ€™s a sequence of
elements

foreach(XmlSchemaParticle p in seq.Items)
{
XmlSchemaElement elem = p as XmlSchemaElement; //Check if particle
in seq is XmlSchemaElement
if (elem != null)
{
Debug.WriteLine(elem.QualifiedName.ToString());
}
}
}
}
}

What can I do to fix the casting problem ? What else can I do ?

Thank you in advance,

Re: Parsing XML Schema (C#)

Stan Kitsis [MSFT]
6/15/2005 4:21:52 PM

Here's an example that shows how to traverse XmlSchema object.

void Start()
{
XmlSchemaComplexType complexType;
foreach (XmlSchemaType type in xs.SchemaTypes.Values)
{
complexType = type as XmlSchemaComplexType;
if (complexType != null)
TraverseParticle(complexType.ContentTypeParticle);
}

foreach (XmlSchemaElement el in xs.Elements.Values)
TraverseParticle(el);
}

void TraverseParticle(complexType.ContentTypeParticle)
{
if (particle is XmlSchemaElement)
{
XmlSchemaElement elem = particle as XmlSchemaElement;

if (elem.RefName.IsEmpty)
{
XmlSchemaType type = (XmlSchemaType)elem.ElementSchemaType;
XmlSchemaComplexType complexType = type as XmlSchemaComplexType;
if (complexType != null && complexType.Name == null)
TraverseParticle(complexType.ContentTypeParticle);
}
}
else if (particle is XmlSchemaGroupBase)
{ //xs:all, xs:choice, xs:sequence
XmlSchemaGroupBase baseParticle = particle as XmlSchemaGroupBase;
foreach (XmlSchemaParticle subParticle in baseParticle.Items)
TraverseParticle(subParticle);
}
}

--
Stan Kitsis
Program Manager, XML Technologies
Microsoft Corporation

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