I have used the "select" keyword and extension method to return an IEnumerable<T>
with LINQ, but I have a need to return a generic Dictionary<T1, T2>
and can't figure it out. The example I learned this from used something in a form similar to the following:
IEnumerable<T> coll = from x in y
select new SomeClass{ prop1 = value1, prop2 = value2 };
I've also done the same thing with extension methods. I assumed that since the items in a Dictionary<T1, T2>
can be iterated as KeyValuePair<T1, T2>
that I could just replace "SomeClass" in the above example with "new KeyValuePair<T1, T2> { ...
", but that didn't work (Key and Value were marked as readonly, so I could not compile this code).
Is this possible, or do I need to do this in multiple steps?
Thanks.
The extensions methods also provide a ToDictionary extension. It is fairly simple to use, the general usage is passing a lambda selector for the key and getting the object as the value, but you can pass a lambda selector for both key and value.
class SomeObject
{
public int ID { get; set; }
public string Name { get; set; }
}
SomeObject[] objects = new SomeObject[]
{
new SomeObject { ID = 1, Name = "Hello" },
new SomeObject { ID = 2, Name = "World" }
};
Dictionary<int, string> objectDictionary = objects.ToDictionary(o => o.ID, o => o.Name);
Then objectDictionary[1]
Would contain the value "Hello"