Adding key/value pairs to a dictionary

Question

i am using a dictionary to store some key value pairs and had a question on the best way to populate the dictionary. I need to do some other operations in order to find and add my key value pairs to my dictionary. After those operations i may have found a key/value to add to the dictionary or i could have found nothing. My question is how i should populate the dictionary. Should i use a function that returns a key value pair if found and otherwise an empty one contained within a dictionary.Add(function()) call? i dont want to add empty key/value pairs to the dictionary so im not sure how the return call for that function would work. Or should i pass the dictionary to the function and add to it if needed? like

function(dictionary) 
{ if (pair found) {dictionary.add(pair)}}

Answer 1

Not sure what you ask here, but here is how I handle dictionary to either add or update a value based on a key:

string key = "some key here";
string value = "your value";
if (myDict.ContainsKey(key))
{
    myDict[key] = value;
}
else
{
    myDict.Add(key, value);
}

You can wrap this in a method if you like:

void AddOrUpdate(Dictionary<string, string> dict, string key, string value)
{
    if (dict.ContainsKey(key))
    {
        dict[key] = value;
    }
    else
    {
        dict.Add(key, value);
    }
}

//usage:
AddOrUpdate(myDict, "some key here", "your value");

You can also use the TryGetValue method but can't see any obvious advantage in this.