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Help needed with Treeview

Posted on 2009-07-13
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Last Modified: 2012-05-07
Dear Experts,

I have made a programm with a treeview on it that loads and saves the nodes to a database.
On the form are also 2 buttons, one for creating a Folder-node and the other for creating
a File-node. The procedures of both buttons looks like this:

procedure TMainForm.AddItem(aText: string; aIndex: Integer; aParent: TTreeNode);
var n: TTreeNode;
  data: TItem;
  parentId: integer;
begin
  parentId := 0;
  if (aParent <> nil) and (TItem(aParent.Data) <> nil) then
    parentId := TItem(aParent.Data).ID;
  data := TItem.Create(AdoQuery1, -1, parentId, 0);
  data.NodeText := aText;
  data.ImageIndex := aIndex;
  n := TTreeNode.Create(TreeView1.Items);
  n.Text := data.NodeText;
  n.ImageIndex := data.ImageIndex;
  n.SelectedIndex := data.ImageIndex;
  TreeView1.Items.AddNode(n, aParent, aText, data, naAddChild);
end;
(*-----------------------------------------*)
procedure TMainForm.NewFolder1Click(Sender: TObject);
var aText: string;
begin
  if InputQuery('Folder', 'Enter a folder name', aText) then
    AddItem(aText, 15, nil);
end;
(*-----------------------------------------*)
procedure TMainForm.NewItem1Click(Sender: TObject);
var aText: string;
begin
  if (TreeView1.Selected <> nil) and (TreeView1.Selected.ImageIndex = 15) then
  begin
     if InputQuery('File', 'Enter a file name', aText) then
      AddItem(aText, 17, TreeView1.Selected);
  end else
    ShowMessage('Select a folder in the treeview first.');
end;
(*-----------------------------------------*)

My question:
1. To make a subfolder node in a folder node.
2. When the folder is selected display image-index 16

I have put the code for loading and saving the nodes to a database
in the code-section, maybe you experts need this too to solve my problem.

Greetings, Peter Kiers

unit Unit1;
 

interface
 

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, DB, ADODB, ComCtrls, StdCtrls, ImgList, ExtCtrls;
 

type

  TForm1 = class(TForm)

    TreeView1: TTreeView;

    Splitter1: TSplitter;

    Panel1: TPanel;

    Button1: TButton;

    Button2: TButton;

    ImageList1: TImageList;

    ADOQuery1: TADOQuery;

    ADOConnection1: TADOConnection;

    Memo1: TMemo;

    FolderBtn: TButton;

    FileBtn: TButton;

    procedure FolderBtnClick(Sender: TObject);

    procedure FileBtnClick(Sender: TObject);

    procedure TreeView1Change(Sender: TObject; Node: TTreeNode);

    procedure FormCreate(Sender: TObject);

    procedure Button2Click(Sender: TObject);

    procedure Button1Click(Sender: TObject);

    procedure Memo1KeyUp(Sender: TObject; var Key: Word;

      Shift: TShiftState);

  private

    { Private declarations }

    procedure savetree(t: ttreeview);

    procedure loadtree(t: TTreeView);

    procedure saveNode(n: TTreeNode);

    function findNode(t:TTreeView; id: integer): TTreeNode;

    procedure AddItem(aText: string; aIndex: Integer; aParent: TTreeNode);

  public

    { Public declarations }

  end;
 

var

  Form1: TForm1;
 

implementation
 

{$R *.dfm}
 

type

  TItem = class(TObject)

  private

    fStatus: byte;

    fParentID: integer;

    fNodeText: string;

    fID: integer;

    fData: string;

    fSaver: TAdoQuery;

    fChanged: Boolean;        

    fSaveImmediate: boolean;

    fIsNew: Boolean;

    fImageIndex: integer;

    procedure SetData(const Value: string);

    procedure SetNodeText(const Value: string);

    procedure SetParentID(const Value: integer);

    procedure SetStatus(const Value: byte);

    procedure SetImageIndex(const Value: integer);

  protected

    procedure Changed; dynamic;

  public

    constructor Create(aSaver: TAdoQuery; AId, AParentID: integer; AStatus: byte);

    constructor LoadFromDataset(aSaver: TAdoQuery);

    procedure BeginUpdate;

    procedure EndUpdate;

    procedure Delete;

    procedure Save;

  published

    property ID: integer read fID write fID;

    property ParentID: integer read fParentID write SetParentID;

    property ImageIndex: integer read fImageIndex write SetImageIndex;

    property Status: byte read FStatus write SetStatus;

    property Data: string read fData write SetData;

    property NodeText: string read fNodeText write SetNodeText;

  end;
 

{ TItem }
 

procedure TItem.BeginUpdate;

begin

  fSaveImmediate := false;                 

end;

(*---------------------------------------------------*)

procedure TItem.Changed;

begin

  fChanged := True;

  if fSaveImmediate then Save;

end;

(*---------------------------------------------------*)

constructor TItem.Create(aSaver: TAdoQuery; AId, AParentID: integer;

  AStatus: byte);

begin

  inherited Create;

  fChanged := False;

  fSaveImmediate := True;

  fIsNew := True;

  fSaver := aSaver;

  fID := AID;

  fParentID := AParentID;

  fStatus := AStatus;

  fNodeText := '';

  fData := '';

end;

(*---------------------------------------------------*)

procedure TItem.EndUpdate;

begin

  fSaveImmediate := True;

  if fChanged then Save;

end;

(*---------------------------------------------------*)

constructor TItem.LoadFromDataset(aSaver: TAdoQuery);

begin

  Create(aSaver, 0, 0, 0);

  if not aSaver.IsEmpty then

  begin

    fId := aSaver.FieldByName('ID').AsInteger;

    fParentID := aSaver.FieldByName('PARENT').AsInteger;

    fStatus := aSaver.FieldByName('STATUS').AsInteger;

    fNodeText := aSaver.FieldByName('NAME').AsString;

    if aSaver.FindField('DATA') <> nil then

      fData := aSaver.FieldByName('DATA').AsString;

    fImageIndex := aSaver.FieldByName('IMAGE_INDEX').AsInteger;

    fIsNew := False;

  end;

end;

(*---------------------------------------------------*)

procedure TItem.Save;

begin

  if fIsNew then

    fSaver.SQL.Text :=

      'insert into tree (parent, name, status, image_index, data) values (:v1, :v2, :v3, :v4, :v5)'

  else

    fSaver.SQL.Text :=

      'update tree set parent = :v1, name = :v2, status = :v3, image_index = :v4, data = :v5 where id = :v6';

  fSaver.Parameters.ParamByName('v1').Value := fparentID;

  fSaver.Parameters.ParamByName('v2').Value := fNodeText;

  fSaver.Parameters.ParamByName('v3').Value := fStatus;

  fSaver.Parameters.ParamByName('v4').Value := fImageIndex;

  fSaver.Parameters.ParamByName('v5').Value := fData;

  if not fIsNew then

    fSaver.Parameters.ParamByName('v6').Value := fId;

  fSaver.ExecSQL;

  if fIsNew then

  begin

    fSaver.SQL.Text :=

      'SELECT id from tree order by id desc';

    fSaver.Open;

    fId := fSaver.FieldByName('ID').asInteger;

    fSaver.Close;

    fIsNew := False;

  end;

  fChanged := False;

end;

(*---------------------------------------------------*)

procedure TItem.SetData(const Value: string);

begin

  if fData <> Value then

  begin

    fData := Value;

    Changed;

  end;

end;

(*---------------------------------------------------*)

procedure TItem.SetImageIndex(const Value: integer);

begin

  if fImageIndex <> Value then

  begin

    fImageIndex := Value;

    Changed;

  end;

end;

(*---------------------------------------------------*)

procedure TItem.SetNodeText(const Value: string);

begin

  if fNodeText <> Value then

  begin

    fNodeText := Value;

    Changed;

  end;

end;

(*---------------------------------------------------*)

procedure TItem.SetParentID(const Value: integer);

begin

  if fParentId <> Value then

  begin

    fParentID := Value;

    Changed;

  end;

end;

(*---------------------------------------------------*)

procedure TItem.SetStatus(const Value: byte);

begin

  if fStatus <> Value then

  begin

    FStatus := Value;

    Changed;

  end;

end;

(*---------------------------------------------------*)

procedure TForm1.Button1Click(Sender: TObject);

begin

  loadTree(treeview1);

end;

(*---------------------------------------------------*)

procedure TForm1.Button2Click(Sender: TObject);

begin

  savetree(treeview1);

end;

(*---------------------------------------------------*)

function TForm1.findNode(t: TTreeView; id: integer): TTreeNode;

var i:integer;

begin

  i:=0;

  while (i<t.items.count) and (TItem(t.items[i].data).ID<>id) do

    inc(i);

  if i<t.items.count then result:=t.items[i]

                     else result:=nil;

end;

(*---------------------------------------------------*)

procedure TForm1.FormCreate(Sender: TObject);

begin

  ADOConnection1.Open;

end;

(*---------------------------------------------------*)

procedure TForm1.loadtree(t: TTreeView);

var

  p, n: TTreeNode;

  data: TItem;

begin

  t.Items.Clear;

  ADOQuery1.SQL.Text := 'select * from tree order by parent asc';

  ADoQuery1.Open;

  while not ADoQuery1.Eof do

  begin

    data := TItem.LoadFromDataset(AdoQuery1);

    p := FindNode(t, data.ParentID);

    n := t.items.AddChildObject(p, data.NodeText, data);

    n.ImageIndex := data.ImageIndex;

    n.SelectedIndex := data.ImageIndex;

    AdoQuery1.Next;

  end;

  AdoQuery1.Close;

end;

(*---------------------------------------------------*)

procedure TForm1.saveNode(n: TTreeNode);

var i, aParent: integer;

  item: TItem;

begin

  item := TItem(n.Data);

  if item <> nil then

  begin

    item.BeginUpdate;

    try

      Item.NodeText := n.Text;

      aParent := 0;

      if (n.Parent <> nil) and (TItem(n.Parent.Data) <> nil) then

        aParent := TItem(n.Parent.Data).ID;

      Item.ParentID := aParent;

      Item.ImageIndex := n.ImageIndex;

    finally

      Item.EndUpdate;

    end;

  end;

  for i := 0 to n.Count-1 do SaveNode(n.Item[i]);

end;

(*---------------------------------------------------*)

procedure TForm1.savetree(t: ttreeview);

var n: TTreeNode;

begin

  n := t.items.getFirstNode;

  while n <> nil do

  begin

    SaveNode(n);

    n := n.getNextSibling;

  end;

end;

(*---------------------------------------------------*)
 

end.

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0
Comment
Question by:peterkiers
2 Comments
 
LVL 11

Accepted Solution

by:
dougaug earned 500 total points
ID: 24846274
Hi Peter,

here are the answers:

1. To make a subfolder node in a folder node.

Try this:

procedure TMainForm.BtnPromoveToFolderClick(Sender: TObject);
begin
  with TreeView1 do
  begin
    // If the selected node has a parent, then it's a file (subfolder node)
    if Selected.Parent <> nil then
    begin
      AddItem(Selected.Text, 15, nil);
      Selected.Delete;
    end;
  end;
end;

2. When the folder is selected display image-index 16
Change your AddItem Method on the referenced line below:

...
  n := TTreeNode.Create(TreeView1.Items);
  n.Text := data.NodeText;
  n.ImageIndex := data.ImageIndex;
  n.SelectedIndex := 16; //<== Change this line
  TreeView1.Items.AddNode(n, aParent, aText, data, naAddChild);
...

I hope this help you.
0
 
LVL 1

Author Comment

by:peterkiers
ID: 24848524
thanks you have helped me alot.

Peter Kiers
0

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