If an array is already sorted and if the type that its elements belong to has implemented IComparable, you can use theBinarySearch method to quickly search for a particular element.
Using our earlier example, with a Person class that implements IComparable (sorts by LastName/FirstName), we can search for a particular Person in a sorted array:
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| Person[] folks = new Person[4];folks[0] = new Person("Bronte", "Emily");folks[1] = new Person("Bronte", "Charlotte");folks[2] = new Person("Tennyson", "Alfred");folks[3] = new Person("Mailer", "Norman");// SortArray.Sort(folks); // C. Bronte, E. Bronte, Mailer, Tennyson// Now search - returns index of 2 (3rd element)int normIndex = Array.BinarySearch(folks, new Person("Mailer", "Norman"));Person norm = folks[normIndex]; // Get reference to Normal |
If you have a property not used for sorting purposes (e.g. Person.Age), you can’t be guaranteed that the object returned as a match actually matches your specified object–for that property. Only properties used for comparison are guaranteed to match in the object returned.