Why var used in foreach for XmlNode does not deduce real type, only object?

Question

Let cls be of type XmlNode

Following statement allows me to access child nodes:

foreach (XmlNode child in cls.ChildNodes)

Now when I try to use var:

foreach (var child in cls.ChildNodes)

then the type of child is not XmlNode, only object. I cannot use child.NodeType, compiler says:

object' does not contain a definition for 'NodeType

Why is this?

Answer 1

ChildNodes is of type XmlNodeList which is defined as

public abstract class XmlNodeList : IEnumerable, IDisposable

Its enumerator returns an object. When you use XmlNode instead of var, .net automatically casts object to XmlNode. But when you use var, child is treated as an object.