Working with XML Strings

Published 16 October 03 10:29 AM | Scott Mitchell

Pop-quiz, hotshot: you have received a payload of XML data in the form of a string from, say, a Web service. Now, you want to perhaps parse this XML data, and perhaps display it in a DataGrid. What do you do, hotshot, what do you do?

Ideally, it would be nice to be able to load the data into one of the many XML-related classes the .NET Framework BCL provides, perhaps the XmlDocument. XmlDocument contains a Load() method, so you think to yourself, "Ok, here's what I'll do:"

// Create a new XmlDocument instance... XmlDocument xmlDoc = new XmlDocument(); // Load the XML string data... xmlDoc.Load("Mitchell");

That won't work, though. The XmlDocument's Load() will accept a string input parameter, but it expects it to be either a URL or a file path where the XML data can be found. Drag. The Load() method, however, can also accept a TextReader instance. Therefore, we can load the XML string data into a StringReader instance, (which is derived from the TextReader class), and then pass in this StringReader into the Load() method!

// Create and populate a StringReader StringReader sr = new StringReader("Mitchell"); // Create a new XmlDocument instance... XmlDocument xmlDoc = new XmlDocument(); // Load the XML string data... xmlDoc.Load(sr);

I recently wrote up a FAQ discussing this in more detail. Also worth checking out is this article by Anthony Hart: DataGrids, DataSets, and XML Strings.

Happy Programming!

Update
A bit of searching the docs has revealed that the XmlDocument class contains a LoadXml() method that loads from XML string data. So... I guess you could use that (assuming you don't need to validate the XML upon loading - for that you still need to use the Load() method). :-) However, for things like XmlTextReaders and whatnot, you will still need to use StringReaders for loading XML string data....