convert dictionary.keyscollection to array of strings

Question

i have a Dictionary<string, List<Order>> and i want to have the list of keys in an array. But when i choose

string[] keys = dictionary.Keys;

this doesn't compile.

how do i convert KeysCollection to array of strings.

Answer 1

Assuming you're using .NET 3.5 or later :

string[] keys = dictionary.Keys.ToArray();

Otherwise, you will have to use the CopyTo method, or use a loop :

string[] keys = new string[dictionary.Keys.Count];
dictionary.Keys.CopyTo(keys, 0);

Answer 2

Unfortunately, I don't have VS nearby to check this, but I think something like this might work:

var keysCol = dictionary.Keys;
var keysList = new List<???>(keysCol);
string[] keys = keysList.ToArray();

where ??? is your key type.

Answer 3

Use this if your keys isn't of type string. It requires LINQ.

string[] keys = dictionary.Keys.Select(x => x.ToString()).ToArray();

Answer 4

With dictionary.Keys.CopyTo (keys, 0);

If you don't need the array (which you usually don't need) you can just iterate over the Keys.