Как реализовать Drag and Drop в TTreeView



Автор: Васильев Василий

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.

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