| FindIndex(PredicateT) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the entire ListT. |
| FindIndex(Int32, PredicateT) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the range of elements in the ListT that extends from the specified index to the last element. |
| FindIndex(Int32, Int32, PredicateT) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the range of elements in the ListT that starts at the specified index and contains the specified number of elements. |