XmlSchemaProviderAttribute Class
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XmlSchemaProviderAttribute Class


When applied to a type, stores the name of a static method of the type that returns an XML schema and a XmlQualifiedName (or XmlSchemaType for anonymous types) that controls the serialization of the type.

Namespace:   System.Xml.Serialization
Assembly:  System.Xml (in System.Xml.dll)


[AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Interface)]
public sealed class XmlSchemaProviderAttribute : Attribute


Initializes a new instance of the XmlSchemaProviderAttribute class, taking the name of the static method that supplies the type's XML schema.


Gets or sets a value that determines whether the target class is a wildcard, or that the schema for the class has contains only an xs:any element.


Gets the name of the static method that supplies the type's XML schema and the name of its XML Schema data type.


When implemented in a derived class, gets a unique identifier for this Attribute.(Inherited from Attribute.)


This API supports the product infrastructure and is not intended to be used directly from your code. Returns a value that indicates whether this instance is equal to a specified object.(Inherited from Attribute.)


Returns the hash code for this instance.(Inherited from Attribute.)


Gets the Type of the current instance.(Inherited from Object.)


When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.(Inherited from Attribute.)


When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.(Inherited from Attribute.)


Returns a string that represents the current object.(Inherited from Object.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Maps a set of names to a corresponding set of dispatch identifiers.(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

Retrieves the type information for an object, which can be used to get the type information for an interface.(Inherited from Attribute.)


Retrieves the number of type information interfaces that an object provides (either 0 or 1).(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Provides access to properties and methods exposed by an object.(Inherited from Attribute.)

The main purpose of the XmlSchemaProviderAttribute is to enable the XmlSchemaExporter class to return a schema when queried by the Web Services Description Language tool (WSDL.exe), or when using the Add Web Reference feature of Visual Studio. You can control the actual schema for the type in the static method.


The target class of the attribute must implement the IXmlSerializable interface.

The MethodName property returns the name of a static method through reflection. The method, which must be implemented, must take a single parameter, an XmlSchemaSet object, which the method populates with an XmlSchema object. The method must also return an XmlQualifiedName object that identifies the data type.

An anonymous complex type cannot be created using a method that returns XmlQualifiedName. Because an anonymous type has no name, and you cannot add an anonymous type to a schema, the anonymous type must be returned as an XmlSchemaType.

The following example applies the XmlSchemaProviderAttribute to a server-side class. When invoked, the method named by the MethodName property creates the schema. This simple implementation reads an existing schema off the disk. However, you can also create a custom schema, if necessary, using the types found in the System.Xml.Schema namespace.

public class SongStream : IXmlSerializable

    private const string ns = "http://demos.Contoso.com/webservices";
    private string filePath;

    public SongStream(){ }

    public SongStream(string filePath)
     this.filePath = filePath;

    // This is the method named by the XmlSchemaProviderAttribute applied to the type.
    public static XmlQualifiedName MySchema(XmlSchemaSet xs)
     // This method is called by the framework to get the schema for this type.
     // We return an existing schema from disk.

     XmlSerializer schemaSerializer = new XmlSerializer(typeof(XmlSchema));
     string xsdPath = null;
     // NOTE: replace the string with your own path.
     xsdPath = System.Web.HttpContext.Current.Server.MapPath("SongStream.xsd");
     XmlSchema s = (XmlSchema)schemaSerializer.Deserialize(
         new XmlTextReader(xsdPath), null);
     xs.XmlResolver = new XmlUrlResolver();

     return new XmlQualifiedName("songStream", ns);

    void IXmlSerializable.WriteXml(System.Xml.XmlWriter writer)
       // This is the chunking code.
       // ASP.NET buffering must be turned off for this to work.

     int bufferSize = 4096;
     char[] songBytes = new char[bufferSize];
     FileStream inFile = File.Open(this.filePath, FileMode.Open, FileAccess.Read);

     long length = inFile.Length;

     // Write the file name.
     writer.WriteElementString("fileName", ns, Path.GetFileNameWithoutExtension(this.filePath));

     // Write the size.
     writer.WriteElementString("size", ns, length.ToString());

     // Write the song bytes.
     writer.WriteStartElement("song", ns);

     StreamReader sr = new StreamReader(inFile, true);
     int readLen = sr.Read(songBytes, 0, bufferSize);

     while (readLen > 0)
         writer.WriteStartElement("chunk", ns);
         writer.WriteChars(songBytes, 0, readLen);

         readLen = sr.Read(songBytes, 0, bufferSize);



    System.Xml.Schema.XmlSchema IXmlSerializable.GetSchema()
     throw new System.NotImplementedException();

    void IXmlSerializable.ReadXml(System.Xml.XmlReader reader)
     throw new System.NotImplementedException();


Universal Windows Platform
Available since 4.5
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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