Solutions.cs

// The solution I've been using up until now
if (Items.ContainsKey(Key)) {
	var item = Items[Key];
}

// Using a single function call to get the value
if (Items.TryGetValue(Key, out var item)) {
	// do something with item
}

// Using exceptions for error handling
try {
	var item = Items[Key];
}
catch (KeyNotFoundException knfe) {

}
finally {

}