XmlReader

XmlReader is an abstract class in the System.Xml namespace that provides a forward-only, read-only cursor for parsing XML data. It is designed for streaming scenarios and is efficient for large documents because it does not load the entire XML into memory.

XmlReader uses a pull-based API. You advance by calling Read and inspect the current node through properties such as NodeType, Name, LocalName, NamespaceURI, and Value. Attributes can be accessed with GetAttribute or MoveToAttribute, and helper methods like ReadStartElement simplify common patterns.

A reader is typically created with XmlReader.Create from a file, a stream, or a text input. In modern code, XmlTextReader is obsolete; XmlReader.Create handles input sources and encoding concerns. XmlReaderSettings can enable validation and configure which nodes to ignore, as well as support for DTD or XML Schema validation.

XmlReader contrasts with DOM-based APIs that load the whole document into memory, such as XmlDocument. It is well suited for large XML files, streaming transformations, and data pipelines where memory efficiency and low latency are important. It can be used alone or in combination with other XML APIs for transformations and validations, making it a versatile option for processing XML without a full in-memory representation. Typical use cases include log parsing, data import, and streaming data processing.