while(0 != reader.ReadChars(buffer, 0, 1))
{// Do something.// Attribute values are not available at this point.
}

<Root><LeafNode>Value</LeafNode><ParentNode><LeafNode>Value</LeafNode></ParentNode>
</Root>

<Root><LeafNode>Value</LeafNode><ParentNode>
<LeafNode>Value</LeafNode></ParentNode>
</Root>

string currentName = reader.LocalName;
while(currentName == reader.LocalName && 0 != reader.ReadChars(buffer, 0, 1))
{// Do something.// Attribute values are not available at this point.
}

List<string> processNodePathList = new List<string> {"/Root/Path/to/Target"};
List<string> bigNodePathList = new List<string> { "/Root/Path/to/Big/Node" }; private static void ProcessBigXmlFile(string sourcePath, string targetPath, IList<string> processNodePathList, IList<string> bigNodePathList)
{var processNodeNameList =processNodePathList.Select(processNodePath => processNodePath.Split(new[] { '/' }, StringSplitOptions.RemoveEmptyEntries)).Select(nodePathParts => nodePathParts[nodePathParts.Length - 1]).ToList();var bigNodeNameList = bigNodePathList.Select(bigNodePath => bigNodePath.Split(new[] { '/' }, StringSplitOptions.RemoveEmptyEntries)).Select(nodePathParts => nodePathParts[nodePathParts.Length - 1]).ToList();var sourceStream = new FileStream(sourcePath, FileMode.Open, FileAccess.Read);var reader = new XmlTextReader(sourceStream);var targetStream = new FileStream(targetPath, FileMode.Create, FileAccess.Write);var writer = new XmlTextWriter(targetStream, Encoding.UTF8);try{var pathStack = new Stack<string>();var readResult = reader.Read();while (readResult){int skipMode = 0;switch (reader.NodeType){case XmlNodeType.Element:{pathStack.Push(reader.Name);writer.WriteStartElement(reader.LocalName);if (reader.HasAttributes){while (reader.MoveToNextAttribute()){writer.WriteAttributeString(reader.LocalName,reader.Value);}reader.MoveToElement();}if (processNodeNameList.Contains(reader.LocalName)){var index = processNodeNameList.IndexOf(reader.LocalName);if (CompareNodePath(pathStack, processNodePathList[index])){// Replace node content
writer.WriteFullEndElement();skipMode = 1;}}else if (bigNodeNameList.Contains(reader.LocalName)){var index = bigNodeNameList.IndexOf(reader.LocalName);if (CompareNodePath(pathStack, bigNodePathList[index])){reader.MoveToContent();var buffer = new char[1024];int len;while (reader.LocalName == bigNodePathList[index] &&(len = reader.ReadChars(buffer, 0, buffer.Length)) > 0){writer.WriteRaw(buffer, 0, len);}writer.WriteFullEndElement();skipMode = 2;}}if (reader.IsEmptyElement){pathStack.Pop();writer.WriteEndElement();}break;}//case XmlNodeType.Attribute://{//    newPackageWriter.WriteAttributeString(oldPackageReader.LocalName, oldPackageReader.Value);//    break;//}case XmlNodeType.Text:{writer.WriteValue(reader.Value);break;}case XmlNodeType.CDATA:{writer.WriteCData(reader.Value);break;}//case XmlNodeType.EntityReference://{//    newPackageWriter.WriteEntityRef(oldPackageReader.Name);//    break;//}//case XmlNodeType.Entity://{//    break;//}case XmlNodeType.ProcessingInstruction:{writer.WriteProcessingInstruction(reader.Name, reader.Value);break;}case XmlNodeType.Comment:{writer.WriteComment(reader.Value);break;}//case XmlNodeType.Document://{//    break;//}case XmlNodeType.DocumentType:{writer.WriteRaw(string.Format("<!DOCTYPE{0} [{1}]>", reader.Name,reader.Value));break;}//case XmlNodeType.DocumentFragment://{//    break;//}//case XmlNodeType.Notation://{//    break;//}case XmlNodeType.Whitespace:{writer.WriteWhitespace(reader.Value);break;}//case XmlNodeType.SignificantWhitespace://{//    break;//}case XmlNodeType.EndElement:{pathStack.Pop();writer.WriteFullEndElement();break;}case XmlNodeType.XmlDeclaration:{writer.WriteStartDocument();break;}}switch (skipMode){case 1:{reader.Skip();pathStack.Pop();readResult = !reader.EOF;break;}case 2:{pathStack.Pop();readResult = !reader.EOF;break;}default:{readResult = reader.Read();break;}}}}finally{writer.Close();targetStream.Close();targetStream.Dispose();reader.Close();sourceStream.Close();sourceStream.Dispose();}
}private static bool CompareNodePath(Stack<string> currentNodePathStack, string compareNodePathString)
{var currentArray = currentNodePathStack.Reverse().ToArray();var compareArray = compareNodePathString.Split(new[] { '/' }, StringSplitOptions.RemoveEmptyEntries);if (compareArray.Length != currentArray.Length){return false;}bool isDifferent = false;for (int i = 0; i < currentArray.Length; i++){if (compareArray[i] != currentArray[i]){isDifferent = true;break;}}return !isDifferent;
}