急... xml 问题

Question

在 Schema 中 choice 方法的用法?

Answer 1

Microsoft XML Core Services (MSXML) 4.0 - XML Schemas

See Also
XML Schema Reference (XSD) | XML Schema Elements

For more information, see the W3C XML Schema Part 1: Structures Recommendation at http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/#element-choice.
choice
Allows one and only one of the elements contained in the selected group to be present within the containing element.

<choice
id = ID
maxOccurs= (nonNegativeInteger | unbounded) : 1
minOccurs= nonNegativeInteger : 1
{any attributes with non-schema Namespace}…>
Content: (annotation?, (element | group | choice | sequence | any)*)
</choice>
Attributes
id
The ID of this element. The id value must be of type ID and be unique within the document containing this element.
Optional.

maxOccurs
The maximum number of times the choice can occur. The value can be an integer greater than or equal to zero. To set no limit on the maximum number, use the string "unbounded". Default value is 1.
Optional.

minOccurs
The minimum number of times the choice can occur. The value can be an integer greater than or equal to zero. To specify that this choice group is optional, set this attribute to zero. Default value is 1.
Optional.

Element Information

Number of occurrences One within <group> and <complexType> elements; otherwise, unlimited.
Parent elements group, choice, sequence, complexType, restriction (simpleContent), extension (simpleContent), restriction (complexContent), extension (complexContent)
Contents annotation, any, choice, element, group, sequence

Example
The following complex type defines an element with one attribute and one and only one element from a choice of four specified elements.

<xs:complexType name="chadState">
<xs:choice minOccurs="1" maxOccurs="1">
<xs:element ref="selected"/>
<xs:element ref="unselected"/>
<xs:element ref="dimpled"/>
<xs:element ref="perforated"/>
</xs:choice>
<xs:attribute name="candidate" type="candidateType"/>
</xs:complexType>
See Also
XML Schema Reference (XSD) | XML Schema Elements

For more information, see the W3C XML Schema Part 1: Structures Recommendation at http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/#element-choice.
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参考资料：ms-help://MS.PSDK.1033/xmlsdk/htm/xsd_ref_5yes.htm