如何使用 XSD 驗證 (LINQ to XML)

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System.Xml.Schema 命名空間包含的擴充方法可針對 XML 結構描述定義語言 (XSD) 檔，簡化 XML 樹狀結構的驗證。 如需詳細資訊，請參閱 Validate 方法的文件。

範例：針對 XmlSchemaSet 驗證 XDocument 物件

下列範例會建立 XmlSchemaSet，然後針對結構描述設定驗證兩個 XDocument 物件。 其中一份文件有效，另一份無效。

string xsdMarkup =
    @"<xsd:schema xmlns:xsd='http://www.w3.org/2001/XMLSchema'>
       <xsd:element name='Root'>
        <xsd:complexType>
         <xsd:sequence>
          <xsd:element name='Child1' minOccurs='1' maxOccurs='1'/>
          <xsd:element name='Child2' minOccurs='1' maxOccurs='1'/>
         </xsd:sequence>
        </xsd:complexType>
       </xsd:element>
      </xsd:schema>";
XmlSchemaSet schemas = new XmlSchemaSet();
schemas.Add("", XmlReader.Create(new StringReader(xsdMarkup)));

XDocument doc1 = new XDocument(
    new XElement("Root",
        new XElement("Child1", "content1"),
        new XElement("Child2", "content1")
    )
);

XDocument doc2 = new XDocument(
    new XElement("Root",
        new XElement("Child1", "content1"),
        new XElement("Child3", "content1")
    )
);

Console.WriteLine("Validating doc1");
bool errors = false;
doc1.Validate(schemas, (o, e) =>
                     {
                         Console.WriteLine("{0}", e.Message);
                         errors = true;
                     });
Console.WriteLine("doc1 {0}", errors ? "did not validate" : "validated");

Console.WriteLine();
Console.WriteLine("Validating doc2");
errors = false;
doc2.Validate(schemas, (o, e) =>
                     {
                         Console.WriteLine("{0}", e.Message);
                         errors = true;
                     });
Console.WriteLine("doc2 {0}", errors ? "did not validate" : "validated");

Dim errors As Boolean = False

Private Sub XSDErrors(ByVal o As Object, ByVal e As ValidationEventArgs)
    Console.WriteLine("{0}", e.Message)
    errors = True
End Sub

Sub Main()
    Dim xsdMarkup As XElement = _
        <xsd:schema xmlns:xsd='http://www.w3.org/2001/XMLSchema'>
            <xsd:element name='Root'>
                <xsd:complexType>
                    <xsd:sequence>
                        <xsd:element name='Child1' minOccurs='1' maxOccurs='1'/>
                        <xsd:element name='Child2' minOccurs='1' maxOccurs='1'/>
                    </xsd:sequence>
                </xsd:complexType>
            </xsd:element>
        </xsd:schema>
    Dim schemas As XmlSchemaSet = New XmlSchemaSet()
    schemas.Add("", xsdMarkup.CreateReader)

    Dim doc1 As XDocument = _
        <?xml version='1.0'?>
        <Root>
            <Child1>content1</Child1>
            <Child2>content1</Child2>
        </Root>

    Dim doc2 As XDocument = _
        <?xml version='1.0'?>
        <Root>
            <Child1>content1</Child1>
            <Child3>content1</Child3>
        </Root>

    Console.WriteLine("Validating doc1")
    errors = False
    doc1.Validate(schemas, AddressOf XSDErrors)
    Console.WriteLine("doc1 {0}", IIf(errors = True, "did not validate", "validated"))

    Console.WriteLine()
    Console.WriteLine("Validating doc2")
    errors = False
    doc2.Validate(schemas, AddressOf XSDErrors)
    Console.WriteLine("doc2 {0}", IIf(errors = True, "did not validate", "validated"))
End Sub

這個範例會產生下列輸出：

Validating doc1
doc1 validated

Validating doc2
The element 'Root' has invalid child element 'Child3'. List of possible elements expected: 'Child2'.
doc2 did not validate

範例：針對檔案中的結構描述驗證檔案中的 XML 文件

下列範例會根據範例 XSD 檔案：客戶與訂單中的結構描述，驗證範例 XML 檔案：客戶與訂單中的 XML 文件是否有效。 接著，它會修改 XML 來源文件。 它會變更第一個客戶上的 CustomerID 屬性。 變更之後，這些訂單將會參考不存在的客戶，因此 XML 文件將不再有效。

XmlSchemaSet schemas = new XmlSchemaSet();
schemas.Add("", "CustomersOrders.xsd");

Console.WriteLine("Attempting to validate");
XDocument custOrdDoc = XDocument.Load("CustomersOrders.xml");
bool errors = false;
custOrdDoc.Validate(schemas, (o, e) =>
                     {
                         Console.WriteLine("{0}", e.Message);
                         errors = true;
                     });
Console.WriteLine("custOrdDoc {0}", errors ? "did not validate" : "validated");

Console.WriteLine();
// Modify the source document so that it won't validate.
custOrdDoc.Root.Element("Orders").Element("Order").Element("CustomerID").Value = "AAAAA";
Console.WriteLine("Attempting to validate after modification");
errors = false;
custOrdDoc.Validate(schemas, (o, e) =>
                     {
                         Console.WriteLine("{0}", e.Message);
                         errors = true;
                     });
Console.WriteLine("custOrdDoc {0}", errors ? "did not validate" : "validated");

Dim errors As Boolean = False

Private Sub XSDErrors(ByVal o As Object, ByVal e As ValidationEventArgs)
    Console.WriteLine("{0}", e.Message)
    errors = True
End Sub

Sub Main()
    Dim schemas As XmlSchemaSet = New XmlSchemaSet()
    schemas.Add("", "CustomersOrders.xsd")

    Console.WriteLine("Attempting to validate")
    Dim custOrdDoc As XDocument = XDocument.Load("CustomersOrders.xml")
    errors = False
    custOrdDoc.Validate(schemas, AddressOf XSDErrors)
    Console.WriteLine("custOrdDoc {0}", IIf(errors, "did not validate", "validated"))

    Console.WriteLine()
    ' Modify the source document so that it won't validate.
    custOrdDoc.<Root>.<Orders>.<Order>.<CustomerID>(0).Value = "AAAAA"
    Console.WriteLine("Attempting to validate after modification")
    errors = False
    custOrdDoc.Validate(schemas, AddressOf XSDErrors)
    Console.WriteLine("custOrdDoc {0}", IIf(errors, "did not validate", "validated"))
End Sub

這個範例會產生下列輸出：

Attempting to validate
custOrdDoc validated

Attempting to validate after modification
The key sequence 'AAAAA' in Keyref fails to refer to some key.
custOrdDoc did not validate

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