Drag & Drop в TTreeView

Вариант 1:

Author: Smike

Source: https://forum.sources.ru

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    TreeView1: TTreeView;
    procedure TreeView1DragDrop(Sender, Source: TObject; X, Y: Integer);
    procedure TreeView1DragOver(Sender, Source: TObject; X, Y: Integer;
      State: TDragState; var Accept: Boolean);
  private
    procedure MoveNode(TargetNode, SourceNode: TTreeNode);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.MoveNode(TargetNode, SourceNode: TTreeNode);
var
  NodeTmp: TTreeNode;
  I: Integer;
begin
  with TreeView1 do
  begin
    // проверяем, является ли целевой элемент предком перетаскиваемого
    NodeTmp := TargetNode.Parent;
    while Assigned(NodeTmp) do
      if NodeTmp = SourceNode then
        Abort
      else
        NodeTmp := NodeTmp.Parent;

    // копируем перетаскиваемый элемент в новосозданный
    NodeTmp := Items.AddChild(TargetNode, SourceNode.Text);
    NodeTmp.Data := SourceNode.Data;

    for I := 0 to SourceNode.Count - 1 do
      MoveNode(NodeTmp, SourceNode.Item[I]);

    Selected := NodeTmp;
    TopItem := NodeTmp.getPrev;
    TargetNode.Expand(True);
  end;
end;

procedure TForm1.TreeView1DragDrop(Sender, Source: TObject; X, Y: Integer);
var
  TargetNode, SourceNode: TTreeNode;
begin
  with TreeView1 do
  begin
    TargetNode := GetNodeAt(X, Y);
    SourceNode := Selected;

    if (TargetNode = SourceNode) or (TargetNode = nil) then
    begin
      EndDrag(False);
      Exit;
    end;
    MoveNode(TargetNode, SourceNode);
    SourceNode.Free;
  end;
end;

procedure TForm1.TreeView1DragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
var
  SourceNode, TargetNode, NodeTmp: TTreeNode;
begin
  if Sender = TreeView1 then
  try
    // скроллинг дерева при перетаскивании
    if Y > TreeView1.Height - 10 then
    begin
      TreeView1.TopItem := TreeView1.TopItem.getNext;
      Sleep(100); // пауза
    end else
      if Y < 10 then
      begin
        TreeView1.TopItem := TreeView1.TopItem.getPrev;
        Sleep(100); // пауза
      end;

    TargetNode := TreeView1.GetNodeAt(X, Y);
    SourceNode := TreeView1.Selected;

    if (TargetNode = nil) or (TargetNode = SourceNode) then Abort;

    Accept := True;
    // проверяем, является ли целевой элемент предком перетаскиваемого
    NodeTmp := TargetNode.Parent;
    while Assigned(NodeTmp) do
      if NodeTmp = SourceNode then
        Abort
      else
        NodeTmp := NodeTmp.Parent;
  except
    Accept := False;
  end;
end;

end.

Вариант 2:

Source: https://www.swissdelphicenter.ch

unit Unit1;

 interface

 uses
   Windows, Messages, SysUtils, Variants, Classes, Controls, Forms,
   Dialogs, StdCtrls, ComCtrls;

 type
   TForm1 = class(TForm)
     TreeView1: TTreeView;
     Label1: TLabel;
     procedure TreeView1DragDrop(Sender, Source: TObject; X, Y: Integer);
     procedure TreeView1DragOver(Sender, Source: TObject; X, Y: Integer;
       State: TDragState; var Accept: Boolean);
   private
     { Private declarations }
     Procedure MoveNode(TargetNode, SourceNode : TTreeNode);
   public
     { Public declarations }
   end;

 var
   Form1: TForm1;

 implementation

 {$R *.dfm}

 // 
// Procedure which will move node and its subnodes 
// 
Procedure TForm1.MoveNode(TargetNode, SourceNode : TTreeNode);
 var
   nodeTmp : TTreeNode;
   i : Integer;
 begin
   with TreeView1 do
   begin
     nodeTmp := Items.AddChild(TargetNode,SourceNode.Text);
     for i := 0 to SourceNode.Count -1 do
     begin
       MoveNode(nodeTmp,SourceNode.Item[i]);
     end;
   end;
 end;


 procedure TForm1.TreeView1DragDrop(Sender, Source: TObject; X, Y: Integer);
 var
   TargetNode, SourceNode : TTreeNode;
 begin
   with TreeView1 do
   begin
     TargetNode := GetNodeAt(X,Y); // Get target node 
    SourceNode := Selected;
     if (TargetNode = nil) then
     begin
       EndDrag(False);
       Exit;
     end;
     MoveNode(TargetNode,SourceNode);
     SourceNode.Free;
   end;
 end;

 procedure TForm1.TreeView1DragOver(Sender, Source: TObject; X, Y: Integer;
   State: TDragState; var Accept: Boolean);
 begin
   if (Sender = TreeView1) then // If TRUE than accept the draged item 
  begin
     Accept := True;
   end;
 end;

 end.