I'm writing my first strategy and am struggling with something that seems ridiculous. I've added some securities in my portfolio, over which I'd now like to iterate.

public void OnData(TradeBars data)
{

foreach(KeyValuePair<string, string> pair in data)
{
// do something with entry.Value or entry.Key
}
}

which generates the bizarre error

Cannot convert type 'System.Collections.Generic.KeyValuePair' to 'System.Collections.Generic.KeyValuePair'

Um? Why is something so basic throwing errors?