lazarus/examples/virtualtreeview/vst_dragdrop/fmain.pas

unit fMain;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
  Laz.VirtualTrees, {$ifdef windows}ActiveX{$else}Laz.FakeActiveX{$endif};

type

  { TMainForm }

  TMainForm = class(TForm)
    ShowHeaderCheckBox: TCheckBox;
    ListBox1: TListBox;
    VirtualStringTree1: TLazVirtualStringTree;
    procedure ListBox1DragDrop(Sender, Source: TObject; X, Y: Integer);
    procedure ListBox1DragOver(Sender, Source: TObject; X, Y: Integer;
      State: TDragState; var Accept: Boolean);
    procedure ShowHeaderCheckBoxChange(Sender: TObject);
    procedure VirtualStringTree1DragDrop(Sender: TBaseVirtualTree;
      Source: TObject; DataObject: IDataObject; Formats: TFormatArray;
      Shift: TShiftState; const Pt: TPoint; var Effect: Integer; Mode: TDropMode);
    procedure VirtualStringTree1DragOver(Sender: TBaseVirtualTree;
      Source: TObject; Shift: TShiftState; State: TDragState; const Pt: TPoint;
      Mode: TDropMode; var Effect: Integer; var Accept: Boolean);
    procedure VirtualStringTree1FreeNode(Sender: TBaseVirtualTree;
      Node: PVirtualNode);
    procedure VirtualStringTree1GetNodeDataSize(Sender: TBaseVirtualTree;
      var NodeDataSize: Integer);
    procedure VirtualStringTree1GetText(Sender: TBaseVirtualTree;
      Node: PVirtualNode; Column: TColumnIndex; TextType: TVSTTextType;
      var CellText: String);
    procedure VirtualStringTree1InitNode(Sender: TBaseVirtualTree; ParentNode,
      Node: PVirtualNode; var InitialStates: TVirtualNodeInitStates);
  private
    { private declarations }
  public
    { public declarations }
  end; 

var
  MainForm: TMainForm;

implementation

{$R *.lfm}

type

  TNodeData = record
    Title: String;
  end;

  PNodeData = ^TNodeData;

{ TMainForm }

procedure TMainForm.VirtualStringTree1GetText(Sender: TBaseVirtualTree;
  Node: PVirtualNode; Column: TColumnIndex; TextType: TVSTTextType;
  var CellText: String);
begin
  CellText := PNodeData(Sender.GetNodeData(Node))^.Title;
end;

procedure TMainForm.VirtualStringTree1InitNode(Sender: TBaseVirtualTree;
  ParentNode, Node: PVirtualNode; var InitialStates: TVirtualNodeInitStates);
begin
  PNodeData(Sender.GetNodeData(Node))^.Title := 'VTV Item ' + IntToStr(Node^.Index);
end;

procedure TMainForm.ListBox1DragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
begin
  Accept := (Source = VirtualStringTree1) or (Source = ListBox1);
end;

procedure TMainForm.ShowHeaderCheckBoxChange(Sender: TObject);
begin
  if ShowHeaderCheckBox.Checked then
    VirtualStringTree1.Header.Options := VirtualStringTree1.Header.Options + [hoVisible]
  else
    VirtualStringTree1.Header.Options := VirtualStringTree1.Header.Options - [hoVisible];
end;

procedure TMainForm.ListBox1DragDrop(Sender, Source: TObject; X, Y: Integer);
var
  Node: PVirtualNode;
begin
  if Source = VirtualStringTree1 then
  begin
    Node := VirtualStringTree1.FocusedNode;
    if Node <> nil then
      ListBox1.Items.Append(VirtualStringTree1.Text[Node, 0]);
  end;
end;

procedure TMainForm.VirtualStringTree1DragDrop(Sender: TBaseVirtualTree;
  Source: TObject; DataObject: IDataObject; Formats: TFormatArray;
  Shift: TShiftState; const Pt: TPoint; var Effect: Integer; Mode: TDropMode);
var
  Node: PVirtualNode;
  NodeTitle: String;
begin
  case Mode of
    dmAbove: Node := Sender.InsertNode(Sender.DropTargetNode, amInsertBefore);
    dmBelow: Node := Sender.InsertNode(Sender.DropTargetNode, amInsertAfter);
    dmNowhere: Exit;
  else
    Node := Sender.AddChild(Sender.DropTargetNode);
  end;
  Sender.ValidateNode(Node, True);
  if Source = ListBox1 then
  begin
    if ListBox1.ItemIndex = -1 then
      NodeTitle := 'Unknow Item from List'
    else
      NodeTitle := ListBox1.Items[ListBox1.ItemIndex];
  end
  else if Source = Sender then
  begin
    if Sender.FocusedNode <> nil then
      NodeTitle := VirtualStringTree1.Text[Sender.FocusedNode, 0]
    else
      NodeTitle := 'Unknow Source Node';
  end
  else
    NodeTitle := 'Unknow Source Control';
  PNodeData(Sender.GetNodeData(Node))^.Title := NodeTitle;
end;

procedure TMainForm.VirtualStringTree1DragOver(Sender: TBaseVirtualTree;
  Source: TObject; Shift: TShiftState; State: TDragState; const Pt: TPoint;
  Mode: TDropMode; var Effect: Integer; var Accept: Boolean);
begin
  Accept := (Sender = VirtualStringTree1) or (Source = ListBox1);
end;

procedure TMainForm.VirtualStringTree1FreeNode(Sender: TBaseVirtualTree;
  Node: PVirtualNode);
begin
  PNodeData(Sender.GetNodeData(Node))^.Title := '';
end;

procedure TMainForm.VirtualStringTree1GetNodeDataSize(Sender: TBaseVirtualTree;
  var NodeDataSize: Integer);
begin
  NodeDataSize := SizeOf(TNodeData);
end;

end.