Select Value of List of KeyValuePair

Question

How can i select the value from the List of keyvaluepair based on checking the key value

List> myList = new         


        

Answer 1

NOTE

The generic Dictionary class, introduced in .NET 2.0, uses KeyValuePair.

ITs better you make use of

Dictionary<TKey, TValue>.ICollection<KeyValuePair<TKey, TValue>>

and use ContainsKey Method to check the the key is there or not ..

Example :

ICollection<KeyValuePair<String, String>> openWith =
            new Dictionary<String, String>();
openWith.Add(new KeyValuePair<String,String>("txt", "notepad.exe"));
openWith.Add(new KeyValuePair<String,String>("bmp", "paint.exe"));
openWith.Add(new KeyValuePair<String,String>("dib", "paint.exe"));
openWith.Add(new KeyValuePair<String,String>("rtf", "wordpad.exe"));

if (!openWith.ContainsKey("txt"))
{
       Console.WriteLine("Contains Given key");
}

---

EDIT

To get value

string value = "";
if (openWith.TryGetValue("tif", out value))
{
    Console.WriteLine("For key = \"tif\", value = {0}.", value);
    //in you case 
   //var list= dict.Values.ToList<Property>(); 
}

in your caseu it will be

var list= dict.Values.ToList<Property>(); 

Answer 2

If you need to use the List anyway I'd use LINQ for this query:

var matches = from val in myList where val.Key == 5 select val.Value;
foreach (var match in matches)
{
    foreach (Property prop in match)
    {
        // do stuff
    }
}

You may want to check the match for null.

Answer 3

Use Dictionary<int, List<Properties>>. Then you can do

List<Properties> list = dict[5];

As in:

Dictionary<int, List<Properties>> dict = new Dictionary<int, List<Properties>>();
dict[0] = ...;
dict[1] = ...;
dict[5] = ...;

List<Properties> item5 = dict[5]; // This works if dict contains a key 5.
List<Properties> item6 = null;

// You might want to check whether the key is actually in the dictionary. Otherwise
// you might get an exception
if (dict.ContainsKey(6))
    item6 = dict[6];

Answer 4

If you're stuck with the List, you can use

myList.First(kvp => kvp.Key == 5).Value

Or if you want to use a dictionary (which might suit your needs better than the list as stated in the other answers) you convert your list to a dictionary easily:

var dictionary = myList.ToDictionary(kvp => kvp.Key);
var value = dictionary[5].Value;