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Interesting concept. I have stored objects as XML as well, though never got really complex in my XML. When W3C created XML Schemas they decided to add some OOP ideas into the language, which through xsd:complexType you can define basic nodes, then have other nodes decend and add-to/override preporties.

For example, you could have an XML document that does this:

   <?xml version="1.0" encoding="utf-8"?><OutLines>  <SchoolOutLine Name="Polymorphism1" Class="CS102">    <Chapters>etc.</Chapters>  </SchoolOutLine>  <WorkOutLine Name="ProcessPO" Region="US">    <Manager>Ted Nuget</Manager>    <Chapters>etc.</Chapters>  </WorkOutLine></OutLines>

In the above listing, you can see that the two "outline" nodes have similar qualities, but also unique qualities. This is easy in OOP, you define a base object and then have a couple descendants that add to it. In XML Schema, it's pretty simple too. Through xsd:complexType, you can define the base element, then have other elements descend from it and add to it.

To do this in xmlArchitect, the easiest thing to do it to first create a basic XML document. Open this document in xmlArchitect through the File|Open command (you'll have to change the file extension to see the XML file as opposed to XSD files) and xmlArchitect will build a basic schema for you. Currently, the schema is simplistic (we have plans for a more advanced wizard-base creation feature) but it's enough to get you going.

Take the elements you want as your base class and extract them out and put them as children of the xsd:schema node. Now, you can make other xsd:element nodes descend from them through their type attribute.

If you open the above file in xmlArchitect, this is the code automatically generated for you:

   <?xml version="1.0"?><xsd:schema xmlns:xsd="www.w3.org/2000/10/XMLSchema">  <xsd:element name="OutLines">    <xsd:complexType>      <xsd:sequence>        <xsd:element name="SchoolOutLine">          <xsd:complexType>            <xsd:sequence>              <xsd:element name="Chapters" type="xsd:string"/>            </xsd:sequence>            <xsd:attribute name="Name" type="xsd:string"/>            <xsd:attribute name="Class" type="xsd:string"/>          </xsd:complexType>        </xsd:element>        <xsd:element name="WorkOutLine">          <xsd:complexType>            <xsd:sequence>              <xsd:element name="Manager" type="xsd:string"/>              <xsd:element name="Chapters" type="xsd:string"/>            </xsd:sequence>            <xsd:attribute name="Name" type="xsd:string"/>            <xsd:attribute name="Region" type="xsd:string"/>          </xsd:complexType>        </xsd:element>      </xsd:sequence>    </xsd:complexType>  </xsd:element></xsd:schema>

Recognizing that the two Outline elements should decend from a common element, we copy it out into it's own 'global' complexType then alter the other two to decend from it, like so:

   <?xml version="1.0"?><xsd:schema xmlns:xsd="www.w3.org/2000/10/XMLSchema">  <xsd:element name="OutLines">    <xsd:complexType>      <xsd:sequence>        <xsd:element name="SchoolOutLine" type="SchoolOutLineType"/>        <xsd:element name="WorkOutLine" type="WorkOutLineType"/>      </xsd:sequence>    </xsd:complexType>  </xsd:element>  <xsd:complexType name="OutLineType">    <xsd:sequence>      <xsd:element name="Chapters" type="xsd:string"/>    </xsd:sequence>    <xsd:attribute name="Name" type="xsd:string"/>  </xsd:complexType>  <xsd:complexType name="SchoolOutLineType" type="OutLineType">    <xsd:complexContent>      <xsd:extension base="OutLineType">        <xsd:attribute name="Class" type="xsd:string"/>      </xsd:extension>    </xsd:complexContent>  </xsd:complexType>  <xsd:complexType name="WorkOutLineType" type="OutLineType">    <xsd:complexContent>      <xsd:extension base="OutLineType">        <xsd:sequence>          <xsd:element name="Manager" type="xsd:string"/>        </xsd:sequence>      </xsd:extension>    </xsd:complexContent>  </xsd:complexType></xsd:schema>

And the XML TreeView still displays what an instance document should look like :) The main items to note here is that complexTypes can be extended through the xsd:extension element. You set the @base attribute to equal the name of another global content, and then you can add elements/attributes to it.

Now, getting this to work in VB is a different point all together. Since VB isn't an OOP language (unlike C++, Java, C# or Delphi), so it will be difficult to mimic the effects of ancestors and extending them etc. The best way will be through Interfaces and COM objects.

-BKN