What is this? A type of class casting or what

Question

Please help! I'm studying C# on my own. Lots of the code, convention and jargons can be tackled easily and I'm able to understand it pretty easy. However, i came across this on my endeavor or my quest to study the best programming language. I've tried flipping books to find what is this thing called. anyway here is the code

((AClass)BClass.BProperties).AMethod(Parameter)

Is this a type of casting or perhaps a substitute of a variable of a particular class? thanks in advanced for your explanation

thank you