CODEWITHSUNDEEP
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ElektroStudios
ElektroStudios

Reputation: 20464

How do I iterate through a dictionary's keys and execute a method for each key in the dictionary using Linq?

How I could fix this LINQ extension? (in C# or VB no matter):

States.Select(Function(item) myMethod(item.Key, item.Value))

States object is a Dictionary, and what I'm trying to reproduce using LINQ is the same as this:

For each item in states
    myMethod(item.Key, item.Value)
Next item

I know that I'm missing something because the Select extension in that way is not the solution... but, I don't know.

Upvotes: 0

Views: 147

Answers (3)

D Stanley
D Stanley

Reputation: 152541

Linq is for querying - it is designed to iterate over a collection and return a result for each item. There are ForEach extension methods out there that just wrap foreach, but in my opinion (and others') they are pointless because they only change the syntax, they do not improve it.

You could fake it out in C# by returning a dummy value:

States.Select(item => {myMethod(item.Key, item.Value); return 0;})

or in VB:

States.Select(Function(item) 
                myMethod(item.Key, item.Value) 
                Return 1 
              End Function)

but I think that just adds confusing noise - a foreach is definitely more appropriate.

Upvotes: 1

Grundy
Grundy

Reputation: 13381

I think you mean ForEach extension, you may use it like this

States.ToList().ForEach(Function(item) myMethod(item.Key, item.Value))

Upvotes: 2

Hogan
Hogan

Reputation: 70523

From your example there is no no way to "reproduce" this in linq. The function does not return a value. If myMethod() returned something you could create a list of all the results like this (C#)

var resultlist = States.Select(item => myMethod(item.Key,item.Value));

But there is no reason to use linq if the method does not return a value -- just use the for each like you had originally.

Upvotes: 1

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