TtreeViewのアイテムを移動させれるコンポについて (ID:16414)

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unit MyTreeView;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, ComCtrls;

type
  TMyTreeView = class(TTreeView)
  private
    procedure DragDrop(Sender, Source: TObject; X, Y: Integer);
    procedure DragOver(Sender, Source: TObject; X, Y: Integer;
                       State: TDragState; var Accept: Boolean);
  public
    constructor Create(AOwner: TComponent); override;
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Samples', [TMyTreeView]);
end;

constructor TMyTreeView.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  DragMode := dmAutomatic;
  OnDragDrop := DragDrop;
  OnDragOver := DragOver;
end;

procedure TMyTreeView.DragDrop(Sender, Source: TObject; X, Y: Integer);
  procedure MoveNode(dstNode, srcNode : TTreeNode);
  var
	aNode : TTreeNode;
	i : Integer;
  begin
    with TMyTreeView(Sender) do begin
      aNode := Items.AddChild(dstNode, srcNode.Text);
      for i := 0 to srcNode.Count - 1 do begin
        MoveNode(aNode, srcNode.Item[i]);
      end;
    end;
  end;
var
  dstNode, srcNode : TTreeNode;
begin
  with TMyTreeView(Sender) do begin
    srcNode := Selected;
    dstNode := GetNodeAt(X, Y);      // dstNodeがnilならRootにDrop
    if dstNode = srcNode then exit;
    MoveNode(dstNode, srcNode);
    srcNode.Delete;
  end;
end;

procedure TMyTreeView.DragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
begin
  Accept := (Sender = Source);
end;

end.

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