XmlEntityReference.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Xml / System / Xml / Dom / XmlEntityReference.cs / 1 / XmlEntityReference.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
//-----------------------------------------------------------------------------
 
// EntityReference objects may be inserted into the structure 
// model when an entity reference is in the source document, or when the user
// wishes to insert an entity reference. Note that  character references and 
// references to predefined entities are considered to be expanded by the
// HTML or XML processor so that characters are represented by their Unicode
// equivalent rather than by an entity reference. Moreover, the XML
// processor may completely expand references to entities while building the 
// structure model, instead of providing EntityReference
// objects. If it does provide such objects, then for a given 
// EntityReference node, it may be that there is no 
// Entity node representing the referenced entity; but if such
// an Entity exists, then the child list of the 
// EntityReference node is the same as that of the
// Entity node. As with the Entity node, all
// descendants of the EntityReference are readonly.
// 
The resolution of the children of the EntityReference (the 
// replacement value of the referenced Entity) may be lazily
// evaluated; actions by the user (such as calling the 
// childNodes method on the EntityReference node) 
// are assumed to trigger the evaluation.
 
namespace System.Xml {

    using System.Diagnostics;
 
    // Represents an entity reference node.
    public class XmlEntityReference : XmlLinkedNode { 
        string name; 
        XmlLinkedNode lastChild;
 
        protected internal XmlEntityReference( string name, XmlDocument doc ) : base( doc ) {
            if ( !doc.IsLoading ) {
                if ( name.Length > 0 && name[0] == '#' ) {
                    throw new ArgumentException( Res.GetString( Res.Xdom_InvalidCharacter_EntityReference ) ); 
                }
            } 
            this.name = doc.NameTable.Add(name); 
            doc.fEntRefNodesPresent = true;
        } 

        // Gets the name of the node.
        public override string Name {
            get { return name;} 
        }
 
        // Gets the name of the node without the namespace prefix. 
        public override string LocalName {
            get { return name;} 
        }

        // Gets or sets the value of the node.
        public override String Value { 
            get {
                return null; 
            } 

            set { 
                throw new InvalidOperationException(Res.GetString(Res.Xdom_EntRef_SetVal));
            }
        }
 
        // Gets the type of the node.
        public override XmlNodeType NodeType { 
            get { return XmlNodeType.EntityReference;} 
        }
 
        // Creates a duplicate of this node.
        public override XmlNode CloneNode(bool deep) {
            Debug.Assert( OwnerDocument != null );
            XmlEntityReference eref = OwnerDocument.CreateEntityReference( name ); 
            return eref;
        } 
 
        //
        // Microsoft extensions 
        //

        // Gets a value indicating whether the node is read-only.
        public override bool IsReadOnly { 
            get {
                return true;        // Make entity references readonly 
            } 
        }
 
        internal override bool IsContainer {
            get { return true;}
        }
 
        internal override void SetParent( XmlNode node ) {
            base.SetParent(node); 
            if ( LastNode == null && node != null && node != OwnerDocument ) { 
                //first time insert the entity reference into the tree, we should expand its children now
                XmlLoader loader = new XmlLoader(); 
                loader.ExpandEntityReference(this);

            }
        } 

        internal override void SetParentForLoad( XmlNode node ) { 
         this.SetParent(  node ); 
        }
 
        internal override XmlLinkedNode LastNode {
            get {
                return lastChild;
            } 
            set { lastChild = value;}
        } 
 
        internal override bool IsValidChildType( XmlNodeType type ) {
            switch (type) { 
                case XmlNodeType.Element:
                case XmlNodeType.Text:
                case XmlNodeType.EntityReference:
                case XmlNodeType.Comment: 
                case XmlNodeType.Whitespace:
                case XmlNodeType.SignificantWhitespace: 
                case XmlNodeType.ProcessingInstruction: 
                case XmlNodeType.CDATA:
                    return true; 

                default:
                    return false;
            } 
        }
 
        // Saves the node to the specified XmlWriter. 
        public override void WriteTo(XmlWriter w) {
            w.WriteEntityRef(name); 
        }

        // Saves all the children of the node to the specified XmlWriter.
        public override void WriteContentTo(XmlWriter w) { 
            // -- eventually will the fix. commented out waiting for finalizing on the issue.
            foreach( XmlNode n in this ) { 
                n.WriteTo( w ); 
            } //still use the old code to generate the output
            /* 
            foreach( XmlNode n in this ) {
                if ( n.NodeType != XmlNodeType.EntityReference )
                n.WriteTo( w );
                else 
                    n.WriteContentTo( w );
            }*/ 
        } 

        public override String BaseURI { 
            get {
                return OwnerDocument.BaseURI;
            }
        } 

        private string ConstructBaseURI( string baseURI, string systemId ) { 
            if ( baseURI == null ) 
                return systemId;
            int nCount = baseURI.LastIndexOf('/')+1; 
            string buf = baseURI;
            if ( nCount > 0 && nCount < baseURI.Length )
                buf = baseURI.Substring(0, nCount);
            else if ( nCount == 0 ) 
                buf = buf + "\\";
            return (buf + systemId.Replace('\\', '/')); 
        } 

        //childrenBaseURI returns where the entity reference node's children come from 
        internal String ChildBaseURI {
            get {
                //get the associate entity and return its baseUri
                XmlEntity ent = OwnerDocument.GetEntityNode( name ); 
                if ( ent != null ) {
                    if ( ent.SystemId != null && ent.SystemId.Length > 0 ) 
                        return ConstructBaseURI(ent.BaseURI, ent.SystemId); 
                    else
                        return ent.BaseURI; 
                }
                return String.Empty;
            }
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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