Moving rows and columns of a StringGrid by code

Problem/Question/Abstract:

The user can move rows and columns of a StringGrid with the mouse. Can it also be done by code? In the help for TCustomGrid you can see the methods MoveColumn and MoveRow, but they are hidden in TStringGrid

Answer:

The user can move rows and columns of a StringGrid with the mouse. Can it also be done by code? In the help for TCustomGrid you can see the methods MoveColumn and MoveRow, but they are hidden in TStringGrid. We can make them accessible again by subclassing TStringGrid and declaring these methods as public:

type
  TStringGridX = class(TStringGrid)
  public
    procedure MoveColumn(FromIndex, ToIndex: Longint);
    procedure MoveRow(FromIndex, ToIndex: Longint);
  end;

The implementation of these methods simply consists of invoking the corresponding method of the ancestor:

procedure TStringGridX.MoveColumn(FromIndex, ToIndex: Integer);
begin
  inherited;
end;

procedure TStringGridX.MoveRow(FromIndex, ToIndex: Integer);
begin
  inherited;
end;

You don't have to register this component in the Components Palette. Use a TStringGrid or any TCustomGrid descendant, and when you need to call these methods simply cast the object to the new class. For example:

procedure TForm1.Button1Click(Sender: TObject);
begin
  TStringGridX(StringGrid1).MoveColumn(1, 3);
end;

Copyright (c) 2001 Ernesto De Spirito
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