[RESOLVED] Quick dictionary question

[nbrege]

When I initialize a new dictionary can I specify the key/value pairs on the same line? Thanks...

[.paul.]

you can with LINQ

[nbrege]

can you post an example?

[.paul.]

ok. but where are you getting the data to put in the dictionary from?

[Sitten Spynne]

Collection Initializers Overview covers all of the cases.

From the "VB can't do anything without introducing extra keywords" department:

Dim lookup = New Dictionary(Of Integer, String) From {{1, "One"}, {2, "Two"}}

[nbrege]

Yes, that's what I was looking for. Thanks!

[.paul.]

that works great in .net4, but in .net3.5:

Dim items(,) As Object = {{1, "Home"}, _
                          {2, "Products"}, _
                          {3, "News"}, _
                          {4, "Contact Us"}}
 
Dim d As Dictionary(Of Integer, String) = Enumerable.Range(0, items.GetLength(0)).Select(Function(i) _
                                        New With { _
                                        .int = CInt(items(i, 0)), _
                                        .str = items(i, 1).ToString}).ToDictionary(Function(kvp) kvp.int, Function(kvp) kvp.str)

[Evil_Giraffe]

I think .paul. just proved that in 3.5 the answer is "No, just call Add afterwards".

[nbrege]

Dim lookup = New Dictionary(Of Integer, String) From {{1, "One"}, {2, "Two"}}

Just a small correction to SS's code, it should be:

Dim lookup As New Dictionary(Of Integer, String) From {{1, "One"}, {2, "Two"}}

[techgnome]

With Infer On, it's the same thing. This is one of those cases where I have no objection to Infer being set to on, since Lookup can only ever be a dictionary.

-tg

[Sitten Spynne]

Yeah, I used to hate type inference and avoid it. Then I started having to work with generic collections that contain collections of generic types. Here's something I had to play with:

Dictionary(Of Foo(Of T), List(Of Foo(Of T)))

One can only type that so many times before wishing for simple preprocessor macros .

[Evil_Giraffe]

Dictionary(Of Foo(Of T), List(Of Foo(Of T)))

One can only type that so many times before wishing for simple preprocessor macros .

Or C#'s syntax:

Dictionary<Foo<T>, List<T>>

How do you stand all those 'Of's floating around? Yuck.</flamebait>

[techgnome]

Shouldn't it have been

Dictionary<Foo<T>, List<Foo<T>>>

-tg

[Evil_Giraffe]

Err... yes, yes it should.

One can only type that so many times before wishing for simple preprocessor macros .

Apparently once, in my case?