How to check for duplicate keys and delete previous value from Dictionary?

Question

I have a Dictionary which contains values with keys. According to my condition, I will have duplicate keys which are strictly not permitted in Dictionary. Now my question is: how to check for the previous duplicate key in the current Dictionary and delete it to add the new?

Answer 1

You can use the ContainsKey() method of the Dictionary to find out whether Dictionary already contains your key or not

dict.ContainsKey(Key)

it returns a true if the Dictionary contains key otherwise returns a false

you don't need to delete the key you can just overwrite the value

if(dict.ContainsKey(Key))
{
dict[key]=YOUR_NEW_VALUE;
}
else
{
 dict.Add ( key,YOUR_NEW_VALUE);
}

Answer 2

My advice would be to think of deleting as simply overwriting the Value member of the matching entry.

if (myDictionary.ContainsKey("key"))
{
    myDictionary["key"] = newValue;
}