Question

Hey I have following code like this

public object RetrieveItemRun(int item)
{
    if (dictionary.ContainsKey(item))
    {
        MessageBox.Show("Retrieving" + item.ToString());
    }
    return dictionary[item];
}

It always crashes when trying to get key of 0, the message box does show so the ContainsKey method is true, but when I try to retrieve the value from the key it crashes saying:

“The given key was not present in the dictionary”

Answer 1

You are trying to retrieve the key independent on if it exists. Try by changing the code to:

   public object RetrieveItemRun(int item)
    {
        if (dictionary.ContainsKey(item))
        {
            MessageBox.Show("Retrieving" + item.ToString());
            return dictionary[item];
        }
        return null;
    }

If exists, then return the item. You original code returns assuming item exits (outside check)