[c#] How do I get the list of keys in a Dictionary?

I only want the Keys and not the Values of a Dictionary.

I haven't been able to get any code to do this yet. Using another array proved to be too much work as I use remove also.

How do I get a List of the Keys in a Dictionary?

I often used this to get the key and value inside a dictionary: (VB.Net)

 For Each kv As KeyValuePair(Of String, Integer) In layerList

 Next

(layerList is of type Dictionary(Of String, Integer))

For a hybrid dictionary, I use this:

List<string> keys = new List<string>(dictionary.Count);
keys.AddRange(dictionary.Keys.Cast<string>());

The question is a little tricky to understand but I'm guessing that the problem is that you're trying to remove elements from the Dictionary while you iterate over the keys. I think in that case you have no choice but to use a second array.

ArrayList lList = new ArrayList(lDict.Keys);
foreach (object lKey in lList)
{
  if (<your condition here>)
  {
    lDict.Remove(lKey);
  }
}

If you can use generic lists and dictionaries instead of an ArrayList then I would, however the above should just work.

To get list of all keys

using System.Linq;
List<String> myKeys = myDict.Keys.ToList();

System.Linq is supported in .Net framework 3.5 or above. See the below links if you face any issue in using System.Linq

Visual Studio Does not recognize System.Linq

System.Linq Namespace

Marc Gravell's answer should work for you. myDictionary.Keys returns an object that implements ICollection<TKey>, IEnumerable<TKey> and their non-generic counterparts.

I just wanted to add that if you plan on accessing the value as well, you could loop through the dictionary like this (modified example):

Dictionary<string, int> data = new Dictionary<string, int>();
data.Add("abc", 123);
data.Add("def", 456);

foreach (KeyValuePair<string, int> item in data)
{
    Console.WriteLine(item.Key + ": " + item.Value);
}

Or like this:

List< KeyValuePair< string, int > > theList =
    new List< KeyValuePair< string,int > >(this.yourDictionary);

for ( int i = 0; i < theList.Count; i++)
{ 
  // the key
  Console.WriteLine(theList[i].Key);
}

You should be able to just look at .Keys:

    Dictionary<string, int> data = new Dictionary<string, int>();
    data.Add("abc", 123);
    data.Add("def", 456);
    foreach (string key in data.Keys)
    {
        Console.WriteLine(key);
    }

I can't believe all these convoluted answers. Assuming the key is of type: string (or use 'var' if you're a lazy developer): -

List<string> listOfKeys = theCollection.Keys.ToList();