Unknown syntax

Truck35 · June 2nd, 2014, 10:59 PM

I'm reading Chapter 11 and there was syntax introduced by the book that I am unfamiliar with. there is an extra set of parathesis used in the syntax in question. I have a problem with the following line:
"((Animal)myEntry.Value).Name"
you don't have to explain everything in the line. Just explain to me why the extra parathesis was used.
Here is the line used in the code:

Code:

foreach (DictionaryEntry myEntry in animalCollection)
{
     Console.WriteLine("New {0} object added to custom collection, " +
                                "Name = {1}", myEntry.Value.ToString(),
                                 ((Animal)myEntry.Value).Name); //This is the line in 
                                                                                     question
}

Thanks in advanced,
Truck35

bhaskargogoi24 · June 3rd, 2014, 01:01 AM

If you see the statement carefully, you will find that the parenthesis used in "((Animal)myEntry.Value).Name);"
is opened in the beginning of the function Console.WriteLine();
Console.WriteLine ("New {0} object added to custom collection, " + // parenthesis opens here
"Name = {1}", myEntry.Value.ToString(),
((Animal)myEntry.Value).Name); //<= it closes here

I hope the problem is solved; :-)

Truck35 · June 3rd, 2014, 11:09 AM

I appreciate you response but you misunderstood my question. I know that all arguments of a method must be enclosed in parenthesis. But if you look at my question I am asking why the last argument has parenthesis around it. I know that the myEntry object must be casted to the animal typed so, that explains the parenthesis around the word Animal. But, why is there parenthesis around the cast to the word value. Please explain if you can. I haven't seen this syntax before.
here and here
|| ||
V V
((Animal)myEntry.Value).Name);

mmorgan30 · June 5th, 2014, 10:57 PM

lets unwrap the code and color code the parens here to get a better view

Code:


Console.WriteLine( "New {0} object added to custom collection, Name = {1}", myEntry.Value.ToString(), ((Animal)myEntry.Value).Name );

the syxtax you are seeing

Code:

((Animal)myEntry.Value).Name

is the value of myEntry.Value being type casted to an animal type then from that animal type the Name property is being de-referenced.

the last set of parens is forcing the evaluation of the type cast first then the de-reference operation of the Name property on the animal type is performed.

Then the last thing to happen is passing the value of the animal Name to the console.WriteLine method