System.Xml.XmlResolver Class

Summary

Resolves external XML resources named by a URI.

C# Syntax:

public abstract class XmlResolver

XmlResolver is used to resolve external XML resources such as entities, DTDs or schemas. It is also used to process include and import elements found in Extensible StyleSheet Language (XSL) stylesheets or XML Schema Definition language (XSD) schemas.

XmlUrlResolver is the default resolver for all classes in the System.Xml namespace. However, you can also create your own resolver. For more information on implementing your own resolver, see the conceptual topic at MSDN: creatingcustomresolver.

System.Xml Namespace

System.Xml.XmlResolver Member List:

Public Properties

Credentials

Write-only When overridden in a derived class, sets the credentials used to authenticate Web requests.

Public Methods

Equals (inherited from System.Object)	See base class member description: System.Object.Equals Derived from System.Object, the primary base class for all objects.
GetEntity	When overridden in a derived class, maps a URI to an object containing the actual resource.
GetHashCode (inherited from System.Object)	See base class member description: System.Object.GetHashCode Derived from System.Object, the primary base class for all objects.
GetType (inherited from System.Object)	See base class member description: System.Object.GetType Derived from System.Object, the primary base class for all objects.
ResolveUri	When overridden in a derived class, resolves the absolute URI from the base and relative URIs.
ToString (inherited from System.Object)	See base class member description: System.Object.ToString Derived from System.Object, the primary base class for all objects.

Protected Constructors

ctor #1

Default constructor. This constructor is called by derived class constructors to initialize state in this type.

Protected Methods

Finalize (inherited from System.Object)	See base class member description: System.Object.Finalize Derived from System.Object, the primary base class for all objects.
MemberwiseClone (inherited from System.Object)	See base class member description: System.Object.MemberwiseClone Derived from System.Object, the primary base class for all objects.

Hierarchy:

• System.Object
• System.Xml.XmlResolver
  • System.Xml.XmlUrlResolver

System.Xml.XmlResolver Member Details

Summary:

Default constructor. This constructor is called by derived class constructors to initialize state in this type.

C# Syntax:

protected XmlResolver();

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Summary

When overridden in a derived class, sets the credentials used to authenticate Web requests.

C# Syntax:

ICredentials Credentials {set;}

If the virtual directory is configured to allow anonymous access, this property does not need to be set. Otherwise, the credentials of the user must be supplied. If credentials are needed but not supplied, the resolver uses default credentials (CredentialCache.DefaultCredentials).

The following C# code sets credentials for the virtual directory "http://localhost/bookstore/inventory.xml"

              XmlTextReader reader = new XmlTextReader("http://localhost/bookstore/inventory.xml");
              NetworkCredential nc = new NetWorkCredential("username", "password", "domain");
              XmlUrlResolver resolver = new XmlUrlResolver();
              resolver.Credentials = nc;
              reader.XmlResolver= resolver;
                 
            

Different credentials can be associated with different URIs, and added to a credential cache. The credentials can then be used to check authentication for different URIs regardless of the original source of the XML.

              NetworkCredential myCred = new NetworkCredential("username","password","domain"); 
              CredentialCache myCache = new CredentialCache(); 
              myCache.Add(new Uri("http://www.contoso.com/"), "Basic", myCred); 
              myCache.Add(new Uri("http://app.contoso.com/"), "Basic", myCred);
              XmlUrlResolver resolver = new XmlUrlResolver();
              resolver.Credentials = myCache;
              reader.XmlResolver = resolver;
                 
            

See XmlUrlResolver.Credentials (in the XmlUrlResolver class) for an example using this property.

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Inherited
See base class member description: System.Object.Equals

C# Syntax:

public virtual bool Equals(    object obj );

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Object.Finalize

C# Syntax:

~XmlResolver();

For more information on members inherited from System.Object click on the link above.

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Summary

When overridden in a derived class, maps a URI to an object containing the actual resource.

C# Syntax:

public abstract object GetEntity(    Uri absoluteUri,    string role,    Type ofObjectToReturn );

absoluteUri

The URI returned from XmlResolver.ResolveUri

role

The current version does not use this parameter when resolving URIs. This is provided for future extensibility purposes. For example, this can be mapped to the xlink:role and used as an implementation specific argument in other scenarios.

ofObjectToReturn

The type of object to return. The current version only returns System.IO.Stream objects.

Return Value:

A System.IO.Stream object or null if a type other than stream is specified.

Exceptions

Exception Type	Condition
XmlException	There is a runtime error (for example, an interrupted server connection).
UriFormatException	The specified URI is not an absolute URI.

This method is used when the caller wants to map a given URI into the object containing the actual resource that the URI represents. The type of object returned is negotiable however the implementation must always support System.IO.Stream.

See XmlUrlResolver.GetEntity (in the XmlUrlResolver class) for an example using this method.

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Inherited
See base class member description: System.Object.GetHashCode

C# Syntax:

public virtual int GetHashCode();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Object.GetType

C# Syntax:

public Type GetType();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Object.MemberwiseClone

C# Syntax:

protected object MemberwiseClone();

For more information on members inherited from System.Object click on the link above.

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Summary

When overridden in a derived class, resolves the absolute URI from the base and relative URIs.

C# Syntax:

public abstract Uri ResolveUri(    Uri baseUri,    string relativeUri );

baseUri

The base URI used to resolve the relative URI

relativeUri

The URI to resolve. The URI can be absolute or relative. If absolute, this value effectively replaces the baseUri value. If relative, it combines with the baseUri to make an absolute URI. The URI to resolve. The URI can be absolute or relative. If absolute, this value effectively replaces the baseUri value. If relative, it combines with the baseUri to make an absolute URI.

Return Value:

The absolute URI or null if the relative URI can not be resolved.

Exceptions

Exception Type	Condition
UriFormatException	The supplied URIs are not absolute.

The absolute URI may be used as the base URI for any subsequent requests for entities that are relative to this URI.

See XmlUrlResolver.ResolveUri (in the XmlUrlResolver class) for an example using this method.

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Inherited
See base class member description: System.Object.ToString

C# Syntax:

public virtual string ToString();

For more information on members inherited from System.Object click on the link above.

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