How to add multiple values to Dictionary in C#?

Question

What is the best way to add multiple values to a Dictionary if I don't want to call ".Add()" multiple times.

Edit: I want to fill it after initiation! there are already some values in the Dictionary!

So instead of

    myDictionary.Add("a", "b");     myDictionary.Add("f", "v");     myDictionary.Add("s", "d");     myDictionary.Add("r", "m");     ... 

I want to do something like this

 myDictionary.Add(["a","b"], ["f","v"],["s","d"]); 

Is there a way to do so?

Answer 1

You can use curly braces for that, though this only works for initialization:

var myDictionary = new Dictionary<string, string> {     {"a", "b"},     {"f", "v"},     {"s", "d"},     {"r", "m"} }; 

This is called "collection initialization" and works for any ICollection<T> (see link for dictionaries or this link for any other collection type). In fact, it works for any object type that implements IEnumerable and contains an Add method:

class Foo : IEnumerable {     public void Add<T1, T2, T3>(T1 t1, T2 t2, T3 t3) { }     // ... }  Foo foo = new Foo {     {1, 2, 3},     {2, 3, 4} }; 

Basically this is just syntactic sugar for calling the Add-method repeatedly. After initialization there are a few ways to do this, one of them being calling the Add-methods manually:

var myDictionary = new Dictionary<string, string>     {         {"a", "b"},         {"f", "v"}     };  var anotherDictionary = new Dictionary<string, string>     {         {"s", "d"},         {"r", "m"}     };  // Merge anotherDictionary into myDictionary, which may throw // (as usually) on duplicate keys foreach (var keyValuePair in anotherDictionary) {     myDictionary.Add(keyValuePair.Key, keyValuePair.Value); } 

Or as extension method:

static class DictionaryExtensions {     public static void Add<TKey, TValue>(this IDictionary<TKey, TValue> target, IDictionary<TKey, TValue> source)     {         if (source == null) throw new ArgumentNullException("source");         if (target == null) throw new ArgumentNullException("target");          foreach (var keyValuePair in source)         {             target.Add(keyValuePair.Key, keyValuePair.Value);         }     } }  var myDictionary = new Dictionary<string, string>     {         {"a", "b"},         {"f", "v"}     };  myDictionary.Add(new Dictionary<string, string>     {         {"s", "d"},         {"r", "m"}     });