Property then Method chaining syntax

Guest User

Hello

Ive seen it in code a few times whereby a property member followed by a method is used...

The syntax is as below:-

property.Method();

or more specifically

db.ShoppingCartItems.InsertOnSubmit();

I just wondered how and why this chaining works\exists?

Regards

Steven

6 Replies

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Vulpes13y ago
Accepted answer
Not quite, Steven.

It's a question of what type of object the db.ShoppingCartItems property is returning, not the type of object on which the property is called.

If this is LINQ to SQL code, then I'd imagine that it's returning a reference to a Table object or something similar.

So, splitting it up into two statements would give you:

Table table = db.ShoppingCartItems;
table.InsertOnSubmit(someItem);
Guest User13y ago
Got it, cheers!

Obviously, as the RHS and LHS of the assignment must be compatible i.e of same types.
Vulpes13y ago
Slight correction:

The ShoppingCartItems property would have a return type of Table.
Guest User13y ago
Ah I see Vulpes thanks

So given

Table table = db.ShoppingCartItems;
table.InsertOnSubmit(someItem);

The ShoppingCartItems property would have a return type of ShoppingCartItem.

And the InsertOnSubmit method is simply being invoked from the table object as per normal syntax...
Guest User13y ago
Thanks Vulpes

So in the example

db.ShoppingCartItems.InsertOnSubmit();

db has a ShoppingCartItems property as well as InsertOnSubmit method therefore the above is a shorthand notation or inline statement for:-

DB db = new DB();
db.ShoppingCartItems;

and

DB db = new DB();
db.InsertOnSubmit();

Combined...
Vulpes13y ago
Chaining in that way will always work as long as the property returns an object of some class and that class has an instance method of that name. It's just the same as doing this:

SomeClass sc = property;
sc.Method();