The Wiert Corner – irregular stream of stuff

It comes down to these cases for XML elements having maxOccurs="1" (which the default for maxOccurs):

1. adding nillable="true" will convert from a regular type to a nullable type.
2. adding minOccurs="0" will add boolean …Specified properties in the generated C# for each element.
3. you can have both nillable="true" and minOccurs="0" in an element which gets you a nullable type and a …Specified property.

Note I’m not considering fixed or default here, nor attributes (that have use instead of minOccurs/maxOccurs, but do not allow for nillable) nor larger values of maxOccurs (which both xsd.exe and xsd2code regard as unbounded).

From the above, XML has a richer type system than C#, so in XML there are subtle a differences between:

1. an explicit nil in the XML element
2. the XML element being absent
3. the XML element being empty.

Hopefully later more text and examples to show how to actually work with this.

• XML Schema nillable=”true” vs minOccurs=”0″ | Dimuthu’s Blog.
• Web services tip: Representations of null in XML Schema.
• c# – Nullable value with xsd.exe genereated class – Stack Overflow.
• Simon Fell > Its just code > Nullable and XxxSpecified.
• Knucklebones: How to NOT use XSD.EXE (it mentions xsd2code which is maintained and XmlGen# which is not maintained).
• Nullable type and XML xsd.exe tool – .NET Development – Windows Tech (xsd.exe .NET DataSets code generation don’t support Nullable).
• c# – Comparison of XSD Code Generators – Stack Overflow.
• .net – Serialize nullable type to optional non-nillable element – Stack Overflow.
• c# – Setting minOccurs=0 in a WSDL using “Specified” pattern not working – Stack Overflow.
• c# – Is it valid to set nillable=true and use the default property in an XML document? – Stack Overflow.
• xml – nillable and minOccurs XSD element attributes – Stack Overflow.
• Web services tip: Representations of null in XML Schema.
• XSD tool appends “Specified” to certain properties/fields when generating C# code – Stack Overflow: watch for semantics differences between C# and XML.
• Using the *Specified Properties in Exchange 2010.
• Name of the blog | Xml Serialization.
• c# – Nullable value with xsd.exe genereated class – Stack Overflow.

Delphi related to minOccurs:

• [WayBack] Problem with optional parameters in a remote function – delphi
• Wayback Machine QC 24056 is unavailable
  • [WayBack] QualityCentral 28062 – Closed – Delphi2006 Win32 WSDL Importer not generating Array Types
    • [WayBack] QualityCentral 30712 – Closed – Win32 WSDL importer does not correctly import complex types
    • [WayBack] QualityCentral 35512 – Closed – WSDL Importer does not generate Array types from MaxOccurs=”unbounded”
• [WayBack] QualityCentral 73096 – Reported – Missing empty line in auto-generated code for node collections
• [RSP-16448] WSDL Importer has problems with tags in berlin – Embarcadero Technologies
• [RSP-19690] XML Data Binding Wizard creates wrong datatype – Embarcadero Technologies
• [WayBack] Delphi XML binding wizard and optional elements – Stack Overflow

Note that xsd2code.codeplex.com (unlike XmlGen#) has at least two forks at github:

• https://github.com/carlmon/Xsd2Code
• https://github.com/kmpm/xsd2code

From the specs:

• XML Schema Part 0: Primer Second Edition.
  • nil values.
  • xsi:nil.
  • default.
  • maxOccurs.
  • minOccurs.
  • use.
  • occurrence constraints.
• XML Schema Part 1: Structures Second Edition.
  • attribute.
  • attribute declarations.
  • element.
  • element declarations.
• XSD.exe XML Schema Binding Support:
  • MaxOccurs Attribute Binding Support.
  • MinOccurs Attribute Binding Support.
  • Default Attribute Binding Support.
  • Fixed Attribute Binding Support.
• XML Schemas (XSD) Reference:
  • Attribute.
  • Element.

–jeroen