| ArrayList: Sort |
Sorts the items in the entire ArrayList or range of elements in ArrayList.
Public Sub Sort( Optional ByRef Index As Variant, Optional ByRef Count As Variant, Optional ByVal Comparer As IComparer )
If comparer is set to Nothing, this method performs a comparison sort (also called an unstable sort); that is, if two elements are equal, their order might not be preserved. In contrast, a stable sort preserves the order of elements that are equal. To perform a stable sort, you must implement a custom IComparer interface.
| Exception | Condition |
|---|---|
| ArgumentOutOfRangeException |
Index is less than zero. -or- Count is less than zero. |
| ArgumentException | Index and Count do not specify a valid range in the ArrayList. |
| InvalidOperationException | An error occurred while comparing two elements. |
The following code example shows how to sort the values in a range of elements in an ArrayList using the default comparer and a custom comparer that reverses the sort order.
There are two modules created for this example. A BAS module containing the Main method and a Class module implementing the IComparer interface.
The following is a Visual Basic Class module named MyReverserClass.
Option Explicit Implements IComparer Private mComparer As New CaseInsensitiveComparer Public Function Compare(ByRef a As Variant, ByRef b As Variant) As Long Compare = mComparer.Compare(b, a) End Function ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' IComparer ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' Private Function IComparer_Compare(a As Variant, b As Variant) As Long IComparer_Compare = Compare(a, b) End Function
The following is a Visual Basic BAS module containing Main start-up method.
Public Sub Main() Dim List As New ArrayList Dim MyComparer As New MyReverserClass List.Add "The" List.Add "QUICK" List.Add "BROWN" List.Add "FOX" List.Add "jumped" List.Add "over" List.Add "the" List.Add "lazy" List.Add "dog" Debug.Print "The ArrayList initially contains the following values:" PrintIndexAndValues List List.Sort 1, 3, Nothing Debug.Print "After sorting from index 1 to index 3 with the default comparer:" PrintIndexAndValues List List.Sort 1, 3, MyComparer Debug.Print "After sorting from index 1 to index 3 with the reverse case-insensitive comparer:" PrintIndexAndValues List End Sub Private Sub PrintIndexAndValues(ByVal List As ArrayList) Dim i As Long For i = 0 To List.Count - 1 Debug.Print CorString.Format(t("\t[{0}]:\t{1}"), i, List(i)) Next Debug.Print End Sub ' This code produces the following output (individual values may vary because they are randomly generate): ' ' The ArrayList initially contains the following values: ' [0]: The ' [1]: QUICK ' [2]: BROWN ' [3]: FOX ' [4]: jumped ' [5]: over ' [6]: the ' [7]: lazy ' [8]: dog ' ' After sorting from index 1 to index 3 with the default comparer: ' [0]: The ' [1]: BROWN ' [2]: FOX ' [3]: QUICK ' [4]: jumped ' [5]: over ' [6]: the ' [7]: lazy ' [8]: dog ' ' After sorting from index 1 to index 3 with the reverse case-insensitive comparer: ' [0]: The ' [1]: QUICK ' [2]: FOX ' [3]: BROWN ' [4]: jumped ' [5]: over ' [6]: the ' [7]: lazy ' [8]: dog