CODEWITHSUNDEEP
c#genericsidictionary
maliks
maliks

Reputation: 1112

How to return all KeyValuePairs of a IDictionary C#

I want to write a method which return all key value pairs containing in a IDictionary as Map.EntrySet() does in java.

I tried as:

For example we define IDictionary as: 

private IDictionary<T, MutableInt> _map = new Dictionary<T, MutableInt>();

The method as: 

public KeyValuePair<T, MutableInt> KeyValuePairSet()
{
   return KeyValuePair<T, MutableInt>(_map.Keys, _map.Values);
}

while returning statement, the error raised is:

KeyValuePair<T, MutableInt> is a type but used like a variable

How can this method be implemented?

Upvotes: 4

Views: 1424

Answers (2)

Riad Baghbanli
Riad Baghbanli

Reputation: 3319

Given:

private IDictionary<T, MutableInt> map = new Dictionary<T, MutableInt>();

If you want to return IEnumerable of KeyValuePairs:

IEnumerable<KeyValuePair<T, MutableInt>> get_pairs()
{
   return map;
}

If you want to return KeyValuePair of keys and values of map:

KeyValuePair<IEnumerable<T>, IEnumerable<MutableInt>> get_pair()
{
   return new KeyValuePair<IEnumerable<T>, IEnumerable<MutableInt>>(map.Keys, map.Values);
}

If you want to return HashSet of KeyValuePairs:

ISet<KeyValuePair<T, MutableInt>> get_pairs()
{
   return new HashSet<KeyValuePair<T, MutableInt>>(map);
}

Upvotes: 3

Scott Chamberlain
Scott Chamberlain

Reputation: 127563

Actually it is fairly easily, because IDictionary<TKey, TValue> implmentents the interface IEnumerable<KeyValuePair<TKey, TValue>> all you need to do is declare your HashSet and pass the dictionary in because HashSet<T> has a constructor that takes in a IEnumerable<T> as its parameter.

public ISet<KeyValuePair<T, MutableInt>> KeyValuePairSet()
{
   return new HashSet<KeyValuePair<T, MutableInt>>(_map);
}

Upvotes: 3

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