Understand Lambda-Expression in the context of linq

Question

If i have the expression:

from p In Product Select p.Name

i understand that p is an Element of Products.

If i have:

Dim allProducts = Products.Select(Function(p) p.Name)

my question is how do i say here that p is an Element of Products?

@ruedi: The question is not clear. Basically there is no difference between p in the query syntax and p i the method syntax. — Tim Schmelter
– Tim Schmelter, Commented Sep 6, 2013 at 8:32
I just try to understand when i say p IN Product... i understand that p is an element of Product. As when i say for each x IN Y. But in the lambda Expression above p is also an element of Products but i just cannot see how this happens. — ruedi
– ruedi, Commented Sep 6, 2013 at 8:35

xanatos · Accepted Answer · 2013-09-06 08:33:33Z

2

Because the VB.NET compiler uses Type inference

Thanks to that, the types of the parameters and of the return value of the anonymous method Function(p) p.Name are discovered through the analysis of the signature of .Select() first (to discover the type of p) and then of the type of p.Name (to discover the return value type)

From Basic Instincts: Lambda Expressions

The introduction of powerful type inference mechanisms means that you don't need to worry about figuring out the type of each variable.

and so on... It's quite long.

answered Sep 6, 2013 at 8:33

xanatos

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1 Comment

ruedi Over a year ago

good explanation, i didnt get how the types are discovered, now i have it. helps a lot, thank u!

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