XmlSchemaUnique Class
Represents the unique element from XML Schema as specified by the World Wide Web Consortium (W3C). This class can be used to identify a unique constraint among a set of elements.
Assembly: System.Xml (in System.Xml.dll)
System.Xml.Schema.XmlSchemaObject
System.Xml.Schema.XmlSchemaAnnotated
System.Xml.Schema.XmlSchemaIdentityConstraint
System.Xml.Schema.XmlSchemaUnique
| Name | Description | |
|---|---|---|
![]() | XmlSchemaUnique() | Initializes a new instance of the XmlSchemaUnique class. |
| Name | Description | |
|---|---|---|
![]() | Annotation | Gets or sets the annotation property.(Inherited from XmlSchemaAnnotated.) |
![]() | Fields | Gets the collection of fields that apply as children for the XML Path Language (XPath) expression selector.(Inherited from XmlSchemaIdentityConstraint.) |
![]() | Id | Gets or sets the string id.(Inherited from XmlSchemaAnnotated.) |
![]() | LineNumber | Gets or sets the line number in the file to which the schema element refers.(Inherited from XmlSchemaObject.) |
![]() | LinePosition | Gets or sets the line position in the file to which the schema element refers.(Inherited from XmlSchemaObject.) |
![]() | Name | Gets or sets the name of the identity constraint.(Inherited from XmlSchemaIdentityConstraint.) |
![]() | Namespaces | Gets or sets the XmlSerializerNamespaces to use with this schema object.(Inherited from XmlSchemaObject.) |
![]() | Parent | Gets or sets the parent of this XmlSchemaObject.(Inherited from XmlSchemaObject.) |
![]() | QualifiedName | Gets the qualified name of the identity constraint, which holds the post-compilation value of the QualifiedName property.(Inherited from XmlSchemaIdentityConstraint.) |
![]() | Selector | Gets or sets the XPath expression selector element.(Inherited from XmlSchemaIdentityConstraint.) |
![]() | SourceUri | Gets or sets the source location for the file that loaded the schema.(Inherited from XmlSchemaObject.) |
![]() | UnhandledAttributes | Gets or sets the qualified attributes that do not belong to the current schema's target namespace.(Inherited from XmlSchemaAnnotated.) |
| Name | Description | |
|---|---|---|
![]() | Equals(Object) | Determines whether the specified object is equal to the current object.(Inherited from Object.) |
![]() | Finalize() | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.) |
![]() | GetHashCode() | Serves as the default hash function. (Inherited from Object.) |
![]() | GetType() | |
![]() | MemberwiseClone() | |
![]() | ToString() | Returns a string that represents the current object.(Inherited from Object.) |
Specifies that an attribute or element value (or a combination of attribute or element values) must be unique within the specified scope. The constraint name must be unique within a schema.
The following example shows the use of the XmlSchemaUnique class.
using System; using System.Xml; using System.Xml.Schema; class XMLSchemaExamples { public static void Main() { XmlSchema schema = new XmlSchema(); // <xs:complexType name="customerOrderType"> XmlSchemaComplexType customerOrderType = new XmlSchemaComplexType(); customerOrderType.Name = "customerOrderType"; // <xs:sequence> XmlSchemaSequence sequence1 = new XmlSchemaSequence(); // <xs:element name="item" minOccurs="0" maxOccurs="unbounded"> XmlSchemaElement item = new XmlSchemaElement(); item.MinOccurs = 0; item.MaxOccursString = "unbounded"; item.Name = "item"; // <xs:complexType> XmlSchemaComplexType ct1 = new XmlSchemaComplexType(); // <xs:attribute name="itemID" type="xs:string"/> XmlSchemaAttribute itemID = new XmlSchemaAttribute(); itemID.Name = "itemID"; itemID.SchemaTypeName = new XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema"); // </xs:complexType> ct1.Attributes.Add(itemID); // </xs:element> item.SchemaType = ct1; // </xs:sequence> sequence1.Items.Add(item); customerOrderType.Particle = sequence1; // <xs:attribute name="CustomerID" type="xs:string"/> XmlSchemaAttribute CustomerID = new XmlSchemaAttribute(); CustomerID.Name = "CustomerID"; CustomerID.SchemaTypeName = new XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema"); customerOrderType.Attributes.Add(CustomerID); // </xs:complexType> schema.Items.Add(customerOrderType); // <xs:element name="ordersByCustomer"> XmlSchemaElement ordersByCustomer = new XmlSchemaElement(); ordersByCustomer.Name = "ordersByCustomer"; // <xs:complexType> XmlSchemaComplexType ct2 = new XmlSchemaComplexType(); // <xs:sequence> XmlSchemaSequence sequence2 = new XmlSchemaSequence(); // <xs:element name="customerOrders" type="customerOrderType" minOccurs="0" maxOccurs="unbounded" /> XmlSchemaElement customerOrders = new XmlSchemaElement(); customerOrders.MinOccurs = 0; customerOrders.MaxOccursString = "unbounded"; customerOrders.Name = "customerOrders"; customerOrders.SchemaTypeName = new XmlQualifiedName("customerOrderType", ""); // </xs:sequence> sequence2.Items.Add(customerOrders); // </xs:complexType> ct2.Particle = sequence2; ordersByCustomer.SchemaType = ct2; // <xs:unique name="oneCustomerOrdersforEachCustomerID"> XmlSchemaUnique element_unique = new XmlSchemaUnique(); element_unique.Name = "oneCustomerOrdersforEachCustomerID"; // <xs:selector xpath="customerOrders"/> element_unique.Selector = new XmlSchemaXPath(); element_unique.Selector.XPath = "customerOrders"; // <xs:field xpath="@customerID"/> XmlSchemaXPath field = new XmlSchemaXPath(); field.XPath = "@customerID"; // </xs:unique> element_unique.Fields.Add(field); ordersByCustomer.Constraints.Add(element_unique); // </xs:element> schema.Items.Add(ordersByCustomer); XmlSchemaSet schemaSet = new XmlSchemaSet(); schemaSet.ValidationEventHandler += new ValidationEventHandler(ValidationCallbackOne); schemaSet.Add(schema); schemaSet.Compile(); XmlSchema compiledSchema = null; foreach (XmlSchema schema1 in schemaSet.Schemas()) { compiledSchema = schema1; } XmlNamespaceManager nsmgr = new XmlNamespaceManager(new NameTable()); nsmgr.AddNamespace("xs", "http://www.w3.org/2001/XMLSchema"); compiledSchema.Write(Console.Out, nsmgr); } public static void ValidationCallbackOne(object sender, ValidationEventArgs args) { Console.WriteLine(args.Message); } }
The following XML file is generated for this code example.
<?xml version="1.0" encoding="IBM437"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:complexType name="customerOrderType"> <xs:sequence> <xs:element name="item" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:attribute name="itemID" type="xs:string"/> </xs:complexType> </xs:element> </xs:sequence> <xs:attribute name="CustomerID" type="xs:string"/> </xs:complexType> <xs:element name="ordersByCustomer"> <xs:complexType> <xs:sequence> <xs:element name="customerOrders" type="customerOrderType" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> </xs:complexType> <xs:unique name="oneCustomerOrdersforEachCustomerID"> <xs:selector xpath="customerOrders"/> <xs:field xpath="@customerID"/> </xs:unique> </xs:element> </xs:schema>
Available since 1.1
Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.


