.NET Framework 4.6 and 4.5
public void Remove(
This method performs a linear search; therefore, the average execution time is proportional to Count. That is, this method is an O(n) operation, where n is Count.
This method determines equality by calling Equals.
The elements that follow the removed element move up to occupy the vacated spot.
Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1
.NET Framework Client Profile
Supported in: 4, 3.5 SP1
Supported in: 3.0, 2.0, 1.0