ExpandXPath Property (TreeViewConfiguration)
The XPath value used to find the internal tree element used to expand and collapse a tree node.
Remarks
Leave this value as a null value if the regular Expand and Collapse methods run correctly.

If the XPath value needed for the Expand operation is different from the XPath value needed for the Collapse operation, use the ExtendedTreeViewConfiguration object.

C# Syntax
public virtual string ExpandXPath {get; set;}