In C#, what does the following syntax do: ((Classname)this.variableName).property

Here is the actual line of code I'm looking at:

ContentVersionCache cvc = ((PageBase)this.Page).cache;

I know this is a really basic question but I've 开发者_如何转开发just started learning C# so go easy on me :)

Cheers Iain

Break it up into smaller pieces:

(PageBase)this.Page

Casts this.Page to a PageBase. This means treating this.Page as if it were a PageBase, even though it may not be declared as such. If it isn't, then this will throw a runtime InvalidCastException!

().cache

Access the cache property or field of the PageBase.

ContentVersionCache cvc = cache;

Store the cache to a local variable called cvc.

It casts the this.Page to a PageBase class .

this.Page is casted to PageBase class then assign its cache property to ContentVersionCache instance cvc

it convert this.Page to PageBase class and then call cache and assign it's value to cvc