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

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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.

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It casts the this.Page to a PageBase class .

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

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