RAD Studio VCL Reference
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Insert entry in list.
procedure Insert(Index: Integer; const Value: T);
__fastcall Insert(int Index, const T Value);
Insert inserts an element Value in the list at the index Index. If the list Count is already equal to Capacity, Capacity is increased.
If Index is not valid for the list, an EArgumentOutOfRangeException exception is raised.
This is an O(n) operation, where n is the number of items in the list.
An OnNotify event occurs indicating an item was inserted in the list.
Delphi Examples:
{ This example demonstrates the usage of the generic TList class. } procedure TForm3.Button1Click(Sender: TObject); var List: TList<Integer>; FoundIndex: Integer; begin { Create a new List } List := TList<Integer>.Create(); { Register a notification call-back } List.OnNotify := ListChanged; { Add a few values to the list } List.AddRange([5, 1, 8, 2, 9, 14, 4, 5, 1]); MessageDlg('Index of first 1 is ' + IntToStr(List.IndexOf(1)), mtInformation, [mbOK], 0); MessageDlg('Index of last 1 is ' + IntToStr(List.LastIndexOf(1)), mtInformation, [mbOK], 0); MessageDlg('List contains elemnt 100? ' + BoolToStr(List.Contains(100)), mtInformation, [mbOK], 0); { Add another element to the list } List.Add(100); MessageDlg('There are ' + IntToStr(List.Count) + ' elements in the list.', mtInformation, [mbOK], 0); { Remove the first occurence of 1 } List.Remove(1); { Delete a few elements form position 0 } List.Delete(0); List.DeleteRange(0, 2); { Extract the remeining 1 from the list } List.Extract(1); { Set the capacity to the actual length } List.TrimExcess(); MessageDlg('There capacity of the list is ' + IntToStr(List.Capacity), mtInformation, [mbOK], 0); { Clear the list } List.Clear(); { Insert some elements } List.Insert(0, 2); List.Insert(1, 1); List.InsertRange(0, [6, 3, 8, 10, 11]); { Sort the list } List.Sort(); { Binary search for the required element } if List.BinarySearch(6, FoundIndex) then MessageDlg('Found element 6 at index ' + IntToStr(FoundIndex), mtInformation, [mbOK], 0); { Reverse the list } List.Reverse(); MessageDlg('The element on position 0 is ' + IntToStr(List.Items[0]), mtInformation, [mbOK], 0); end; procedure TForm3.ListChanged(Sender: TObject; const Item: Integer; Action: TCollectionNotification); begin { This method is called by the List everytime a change occurs } if Action = cnAdded then MessageDlg('Element added: ' + IntToStr(Item), mtInformation, [mbOK], 0) else if Action = cnRemoved then MessageDlg('Element removed: ' + IntToStr(Item), mtInformation, [mbOK], 0) else if Action = cnExtracted then MessageDlg('Element extracted: ' + IntToStr(Item), mtInformation, [mbOK], 0) end;
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