I have a table Customers
that is linked to another table Addresses
. The Addresses table has a Primary Key made up of {CustomerID, LanguageID}.
I would like to wrtie a LINQ query where I instantiate a type and populate its
Dictionary<string, Address> Addresses {get;set;}
property with the addresses in the Address table. Each Langauge is to become the key in the dictionary.
Like so:
from c in customers
from a in c.Addresses
select new DataContainer
{
ID = c.CustomerId,
...
Addresses.Add(a.LanguageId, a),
...
};
I know that I really can't do the .Add() call in an object initializer, but is there a way to make that work?
Note: I could of course create the type as usual and then go back in and populate the Addresses property explicitely.
I don't remember from memory if following code will compile, but you can try something like this:
from c in customers
from a in c.Addresses
select new DataContainer
{
Addresses = new Dictionary<string, Address> {{a.LanguageId, a}};
};
Or you can try following solution: Instantiating a Dictionary from a LINQ projection
A safe way to do this is like so:
If DataContainer
looks like this:
public class DataContainer
{
public string ID { get; set; }
public Address Address { get; set; }
}
You can do this:
from c in customers
from a in c.Addresses
select new DataContainer
{
ID = c.CustomerId,
Address = a
};
var dic = new Dictionary<string, Address>();
foreach (var n in query)
{
dic.Add(ID,a);
}
Or for short do this:
var dic = query.ToDictionary<DataContainer, string, Address>(n => n.ID, n => n.a);
In response to John's comment for henk.
I wrote a Dictionary extension
public static Dictionary<T, K> Build<T, K>(this Dictionary<T, K> dictionary, T key, K value)
{
dictionary[key] = value;
return dictionary;
}
Now you can do something like this:
from c in customers
from a in c.Addresses
select new DataContainer
{
Addresses = new Dictionary<string, Address>()
.Build(a.LanguageId, a)
};
For me it does work. :)
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