How to parse a XSD file

Question

I am writing a code generation tool that will take in a XSD file generated from Visual Studio's Data Set Generator and create a custom class for each column in each table. I already understand how to implement a IVsSingleFileGenerator to do the code generation and how to turn that single file generator in to a multi-file generator. However it seems the step I am having the most trouble with is the one that should be the most simple. I have never really worked with XML or XML-Schema before and I have no clue what is the correct way to iterate through a XSD file and read out the column names and types so I can build my code.

Any recommendation on a tutorial on how to read a XSD file? Also any recommendations on how to pull each xs:element that represents a column out and read its msprop:Generator_UserColumnName, type, and msprop:Generator_ColumnPropNameInTable properties from each element.

Answer 1

You'll want to create an XmlSchemaSet, read in your schema and then compile it to create an infoset. Once you've done that, you can start iterating through the document

XmlSchemaElement root = _schema.Items[0] as XmlSchemaElement;
XmlSchemaSequence children = ((XmlSchemaComplexType)root.ElementSchemaType).ContentTypeParticle as XmlSchemaSequence;
foreach(XmlSchemaObject child in children.Items.OfType<XmlSchemaElement>()) {
    XmlSchemaComplexType type = child.ElementSchemaType as XmlSchemaComplexType;
    if(type == null) {
        // It's a simple type, no sub-elements.
    } else {
        if(type.Attributes.Count > 0) {
            // Handle declared attributes -- use type.AttributeUsers for inherited ones
        }
        XmlSchemaSequence grandchildren = type.ContentTypeParticle as XmlSchemaSequence;
        if(grandchildren != null) {
            foreach(XmlSchemaObject xso in grandchildren.Items) {
                if(xso.GetType().Equals(typeof(XmlSchemaElement))) {
                    // Do something with an element.
                } else if(xso.GetType().Equals(typeof(XmlSchemaSequence))) {
                    // Iterate across the sequence.
                } else if(xso.GetType().Equals(typeof(XmlSchemaAny))) {
                    // Good luck with this one!
                } else if(xso.GetType().Equals(typeof(XmlSchemaChoice))) {
                    foreach(XmlSchemaObject o in ((XmlSchemaChoice)xso).Items) {
                        // Rinse, repeat...
                    }
                }
            }
        }
    }
}

Obviously you'll want to put all the child handling stuff in a separate method and call it recursively, but this should show you the general flow.