Solved

Delete a treeview node

Posted on 2009-05-20
9
340 Views
Last Modified: 2012-05-07
Dear experts,

What i want is:
When a user deletes a folder-node in the treeview, a message must appear:

"Are you sure that you want to delete the folder "xxxx"?
All folders, subfolders, items and subitems will be permanently
deleted."

When the user clicks OK the folder will be deleted.

The same i want when the user deletes a file, then this message will appear:

"Are you sure that you want to delete the item "xxxx"?"

And afcourse where i have put the xxxx their has to the file or folder name.

Who can help me, and want to earn 500p's

Greetings, Peter Kiers
0
Comment
Question by:peterkiers
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9 Comments
 
LVL 6

Expert Comment

by:bokist
ID: 24431374
This should do the task

procedure TForm1.TreeViewKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
var
   node : TTreeNode;
   mess, str : string;
   key_stat : integer;
begin
   if Key = VK_DELETE then
      begin
      Node := Treeview.Selected;
      str := Node.Text;
      Case Node.Level of
         0 : mess := 'Are you sure that you ' + #13 + 'want to delete the folder : ' +  #13 + #13 + str + '   ???'  + #13 +  '    ';
         1 : mess := 'Are you sure that you ' + #13 + 'want to delete the item : '  +  #13 + #13 + str + '   ???'  + #13 +  '    ';
      end;
      with Application do
         begin
         NormalizeTopMosts;
         key_stat := MessageBox(pchar(mess), '         Confirmation', MB_YESNO);
         RestoreTopMosts;
      end;
      if key_stat = 7 then  Exit;         // 6 - YES ; 7 - N0
      TreeView.Items.Delete(Treeview.Selected);
   end;
end;
0
 
LVL 12

Expert Comment

by:Hypo
ID: 24431397
How does your code distinguish what nodes are folder nodes and what nodes are file nodes? If you could you provide us with an example of your code as it is today, then it would be much easier to help you?

/Hypo
0
 
LVL 38

Accepted Solution

by:
Geert Gruwez earned 250 total points
ID: 24431681
using the imageindex if it's still from my samples ...


procedure TForm1.TreeViewKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
var
  node : TTreeNode;
  mess, str : string;
begin
  if Key = VK_DELETE then
  begin
    Node := Treeview.Selected;
    if Assigned(Node) then 
    begin
      case Node.ImageIndex of
        0 : mess := 'folder';
        1 : mess := 'item';
      end;
      mess := Format('Are you sure that you want to delete the %s : %s ???', [mess, Node.Text]);
      if MessageDlg(mess, mtConfirmation, [mbYes, mbNo], 0) = mrYes then 
        TreeView.Items.Delete(Node);
    end else 
      ShowMessage('Please select something to delete !');
  end;
end;

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LVL 1

Author Comment

by:peterkiers
ID: 24433421
The code I have received is not what I have asked.

Peter
(*----------------------------------------*)
procedure TMainForm.AddItem(aText: string; aIndex: Integer; aParent: TTreeNode);
var item: TTreeNode;
begin
  item := TTreeNode.Create(TreeView1.Items);
  item.Text := aText;
  item.ImageIndex := aIndex;
  item.SelectedIndex := aIndex;
  TreeView1.Items.AddNode(item, aParent, aText, nil, naAddChild);
  item.MakeVisible;
  TreeView1.Selected := item;
end;
(*----------------------------------------*)
procedure TMainForm.NewFolder1Click(Sender: TObject);
var aText: string;
  aParent: TTreeNode;
begin
  aParent := nil;
  if TreeView1.Selected <> nil then
  begin
    if TreeView1.Selected.ImageIndex = 0 then
      aParent := TreeView1.Selected
  end;
  if InputQuery('Folder', 'Enter a folder name', aText) then
     begin
     if length(trim(aText)) = 0 then
        begin
        showmessage('You must enter a folder name');
        Exit;
     end;
     AddItem(aText, 0, aParent);
   end;
end;
(*----------------------------------------*)
procedure TMainForm.NewItem1Click(Sender: TObject);
var aText: string;
begin
  if (TreeView1.Selected <> nil) and (Treeview1.Selected.ImageIndex = 0) then
  begin
    if InputQuery('New Item', 'New Item Name:', aText) then
       begin
       if length(trim(aText)) = 0 then
          begin
          showmessage('You must enter an item name');
          Exit;
       end;
       AddItem(aText, 1, TreeView1.Selected);
     end;
  end else 
    ShowMessage('Select a folder in the treeview first.');
end;

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0
 
LVL 1

Author Comment

by:peterkiers
ID: 24433473
I want when the user clicks on the delete-button while a item-node is selected
the message: "Are you sure that you want to delete the item "xxxx"?" will be displayed,
if the user presses OK de item-node then will be deleded

When the user clicks on the delete-button while a folder-node is selected
the message: "Are you sure that you want to delete the folder "xxxx"?
All folders, subfolders, items and subitems will be permanently
deleted." will be displayed,
if the user presses OK the folder-node then will be deleded
0
 
LVL 6

Expert Comment

by:bokist
ID: 24439048
If you want to delete treeview items on button click,
here is the code (with some Geert's suggestions included)


procedure TForm1.DeleteItemClick(Sender: TObject);
var
   node : TTreeNode;
   mess, str : string;
   key_stat : integer;
begin
    Node := Treeview.Selected;
    if Assigned(Node) then
       begin
       str := Node.Text;
       mess := 'Are you sure that you ' + #13 + 'want to delete the';
       Case Node.Level of
         0 : mess := mess + ' folder : ';
         1 : mess := mess + ' item : ';
       end;
       mess := mess + #13 + #13 + str + '   ???'  + #13 +  '    ';
       with Application do
         begin
         NormalizeTopMosts;
         key_stat := MessageBox(pchar(mess), '         Confirmation', MB_YESNO);
         RestoreTopMosts;
       end;
       if key_stat = 7 then  Exit;         // 6 - YES ; 7 - N0
       TreeView.Items.Delete(Treeview.Selected);
       end
    else ShowMessage('Select a folder in the treeview first.');
end;
0
 
LVL 6

Assisted Solution

by:bokist
bokist earned 250 total points
ID: 24439121
Oops, I didn't change the message

procedure TForm1.DeleteItemClick(Sender: TObject);
var
   node : TTreeNode;
   mess, str : string;
   key_stat : integer;
begin
    Node := Treeview.Selected;
    if Assigned(Node) then
       begin
       str := Node.Text;
       mess := 'Are you sure that you want to delete the';
       Case Node.Level of
         0 : mess := mess + ' folder : ' +#13+#13 + str + '   ???' +#13+
                    'All folders, subfolders, items and subitems' +#13+ 'will be permanently deleted !!' +#13;
         1 : mess := mess + ' item : ' +#13+#13 + str + '   ???' + #13;
       end;
       with Application do
         begin
         NormalizeTopMosts;
         key_stat := MessageBox(pchar(mess), '         Confirmation', MB_YESNO);
         RestoreTopMosts;
       end;
       if key_stat = 7 then  Exit;         // 6 - YES ; 7 - N0
       TreeView.Items.Delete(Treeview.Selected);
       end
    else ShowMessage('Select a folder in the treeview first.');
end;
0
 
LVL 1

Author Comment

by:peterkiers
ID: 24439507
Thanks for everything.

Greetings,

Peter Kiers
0
 
LVL 1

Author Comment

by:peterkiers
ID: 24860615
I guess no one will download the example. So i have put the code in the code-section.

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;
    ADOQuery1: TADOQuery;
    ADOConnection1: TADOConnection;
    FolderBtn: TButton;
    FileBtn: TButton;
    ImageList1: TImageList;
    RichEdit1: TRichEdit;
    Button3: TButton;
    procedure Button3Click(Sender: TObject);
    procedure RichEdit1KeyUp(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    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);
    
  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.Delete;
begin
//
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.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 TForm1.Button1Click(Sender: TObject);
begin
  loadTree(treeview1);
end;
(*---------------------------------------------------*)
procedure TForm1.Button2Click(Sender: TObject);
begin
  savetree(treeview1);
end;
procedure TForm1.Button3Click(Sender: TObject);
var
   node : TTreeNode;
   mess, str : string;
   key_stat : integer;
begin
    Node := Treeview1.Selected;
    if Assigned(Node) then
       begin
       str := Node.Text;
       mess := 'Are you sure that you want to delete the';
       Case Node.Level of
         0 : mess := mess + ' folder : ' +#13+#13 + str + '   ???' +#13+
                    'All folders, subfolders, items and subitems' +#13+ 'will be permanently deleted !!' +#13;
         1 : mess := mess + ' item : ' +#13+#13 + str + '   ???' + #13;
       end;
       with Application do
         begin
         NormalizeTopMosts;
         key_stat := MessageBox(pchar(mess), '         Confirmation', MB_YESNO);
         RestoreTopMosts;
       end;
       if key_stat = 7 then  Exit;         // 6 - YES ; 7 - N0
       TreeView1.Items.Delete(Treeview1.Selected);
       end
    else ShowMessage('Select a folder in the treeview first.');
end;
(*---------------------------------------------------*)
procedure TForm1.FileBtnClick(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;
(*---------------------------------------------------*)
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.FolderBtnClick(Sender: TObject);
var aText: string;
  aParent: TTreeNode;
begin
  aParent := nil;
  if TreeView1.Selected <> nil then
  begin
    if TreeView1.Selected.ImageIndex = 15 then
      aParent := TreeView1.Selected
    else
    begin
      ShowMessage('Select a folder first');
      Exit;
    end;
  end;
  if InputQuery('Folder', 'Enter a folder name', aText) then
    AddItem(aText, 15, aParent);
end;
(*---------------------------------------------------*)
procedure TForm1.FormCreate(Sender: TObject);
var
  conn_str:string;
begin
  conn_str:='provider=Microsoft.Jet.OLEDB.4.0;Persist Security Info=False;Data Source=';
  conn_str:=conn_str+IncludeTrailingPathDelimiter(ExtractFilePath(Application.Exename));
  conn_str:=conn_str+'test.pkd;';
  ADOConnection1.Connected:=False;
  ADOConnection1.ConnectionString:=conn_str;
  ADOConnection1.Connected:=True;
  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;
(*---------------------------------------------------*)
procedure TForm1.TreeView1Change(Sender: TObject; Node: TTreeNode);
begin
  RichEdit1.Text := '';
  if (Node <> nil) and (Node.ImageIndex = 15) then
    RichEdit1.Text := TItem(Node.Data).Data;
end;
(*---------------------------------------------------*)
procedure TForm1.RichEdit1KeyUp(Sender: TObject; var Key: Word;
  Shift: TShiftState);
  var n: TTreeNode;
begin
        n := TreeView1.Selected;
        if (n <> nil) and (n.ImageIndex = 15) then
        begin
        TItem(n.Data).fSaveImmediate := False;
         TItem(N.Data).Data := RichEdit1.Text;
         end;
end;
(*---------------------------------------------------*)
end.

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