System.Xml.XmlReader.IsTextualNode C# (CSharp) Method

        static internal bool IsTextualNode(XmlNodeType nodeType)
        {
#if DEBUG
            // This code verifies IsTextualNodeBitmap mapping of XmlNodeType to a bool specifying
            // whether the node is 'textual' = Text, CDATA, Whitespace or SignificantWhitespace.
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.None)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.Element)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.Attribute)));
            Debug.Assert(0 != (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.Text)));
            Debug.Assert(0 != (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.CDATA)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.EntityReference)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.Entity)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.ProcessingInstruction)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.Comment)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.Document)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.DocumentType)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.DocumentFragment)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.Notation)));
            Debug.Assert(0 != (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.Whitespace)));
            Debug.Assert(0 != (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.SignificantWhitespace)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.EndElement)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.EndEntity)));
            Debug.Assert(0 == (s_isTextualNodeBitmap & (1 << (int)XmlNodeType.XmlDeclaration)));
#endif
            return 0 != (s_isTextualNodeBitmap & (1 << (int)nodeType));
        }

        public virtual string ReadString()
        {
            if (this.ReadState != ReadState.Interactive)
            {
                return("");
            }
            this.MoveToElement();
            if (this.NodeType == XmlNodeType.Element)
            {
                if (this.IsEmptyElement)
                {
                    return("");
                }
                if (!this.Read())
                {
                    throw new InvalidOperationException(Res.GetString(2));
                }
                if (this.NodeType == XmlNodeType.EndElement)
                {
                    return("");
                }
            }
            string str = "";

            while (XmlReader.IsTextualNode(this.NodeType))
            {
                str += this.Value;
                if (!this.Read())
                {
                    throw new InvalidOperationException(Res.GetString(2));
                }
            }
            return(str);
        }