Code Samples

Last Updated: 6/2/2009

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Home » Class Reference » TIWTreeView

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Topics in this section:
Property UserData
Property CSS
Event OnPlusMinus
Property DoServerSidePlusMinus
ScrollToName
TIWTreeViewItems.Add
Code Samples

This is a snipet of code you can use to load data to your IWTreeView. Here we show a pratical example on how to change the CSS, the Hint and the Node image for the TreeNode.

procedure TfrmTreeView.FillTreeView(const TreeView: TIWTreeView;
  const Node: TIWTreeViewItem; const Dataset: TDataset; const Field, KeyField, CSSField: String;
  const Hint: String; FakeNode: Boolean; NodeLevel: Integer; ClearNode: Boolean; CheckCrazyOffer: Boolean);
var
  TreeNode: TIWTreeViewItem;
begin
  Dataset.AutoCalcFields := False;
  try
    TreeView.Items.BeginUpdate;
    Dataset.DisableControls;
    Dataset.First;
    if (Node <> Nil) and ClearNode then
      Node.SubItems.Clear;
    while not Dataset.EOF do
      begin
        TreeNode := TreeView.Items.Add(Node);
        TreeNode.Expanded := False;
        TreeNode.Caption := Dataset.FieldByName(Field).AsString;
        TreeNode.Hint := HintItem(TreeNode.Caption);
        if not StrIsEmpty(CSSField) then
          TreeNode.CSS := CSSItem(Dataset.FieldByName(CSSField).AsInteger;
        else
          TreeNode.CSS := CSSItem(-1);

       // using a fake node instead of loading all the user data at once in the treeview
       // it gives the user a visual effect that there is more data under the node

        if FakeNode then
          TreeView.Items.Add(TreeNode);
        TreeNode.UserData := TNodeUserData.Create;
        TNodeUserData(TreeNode.UserData).NodeLevel := NodeLevel;
        TNodeUserData(TreeNode.UserData).RecordKey := Dataset.FieldByName(KeyField).AsInteger;
        if CheckCrazyOffer then begin
          if Dataset.FieldByName('crazy_offer').AsString = 'Y' then
            // Changing the image of the TreeNode based on a specif condition of the current record
            TreeNode.ItemImages.DocumentImage.Filename := 'hot.gif';
        end;
        Dataset.Next;
      end
  finally
    Dataset.EnableControls;
    Dataset.AutoCalcFields := True;
    TreeView.Items.EndUpdate;
  end;
end;

How to use the method FillTreeView

procedure TfrmTreeView.BuildHierarchy;
var
  i: Integer;
  Node: TIWTreeViewItem;
begin
  try
    if not UserSession.Material.Active then
      UserSession.Material.Open;
    if not UserSession.Classificacao.Active then
      UserSession.Classificacao.Open;
    if not UserSession.Espessura.Active then
      UserSession.Espessura.Open;

    TreeView.Items.BeginUpdate;
    try
      FillTreeView(TreeView, Nil, UserSession.Material.Data, 'ds_eng', 'id_mat', '', '', False, NodeLevelMaterial);
      for i := 0 to TreeView.Items.Count - 1 do begin
        Node := TreeView.Items[i];
        if TNodeUserData(Node.UserData).NodeLevel = NodeLevelMaterial then begin
          UserSession.Espessura.Data.Filter := 'id_mat = ' + IntToStr(TNodeUserData(Node.UserData).Chave);
          UserSession.Espessura.Data.Filtered := True;
          UserSession.Espessura.Data.First;
          FillTreeView(TreeView, Node, UserSession.Espessura.Data, 'ds_esp', 'id_esp', '', '', False, NodeLevelEspessura);
          TNodeUserData(Node.UserData).DetailLoaded := True;
        end;
      end;

      UserSession.Espessura.Data.Filter := '';
      UserSession.Espessura.Data.Filtered := False;

      for i := 0 to TreeView.Items.Count - 1 do begin
        Node := TreeView.Items[i];
        if TNodeUserData(Node.UserData).NodeLevel = NodeLevelEspessura then begin
          UserSession.Classificacao.Data.Filter := 'id_esp = ' + IntToStr(TNodeUserData(Node.UserData).Chave) + ' and id_mat = ' + IntToStr(TNodeUserData(Node.ParentItem.UserData).Chave); ;
          UserSession.Classificacao.Data.Filtered := True;
          UserSession.Classificacao.Data.First;
          FillTreeView(TreeView, Node, UserSession.Classificacao.Data, 'ds_cla', 'id_cla', '', '', False, NodeLevelClassificacao);
          TNodeUserData(Node.UserData).DetailLoaded := False;
        end;
      end;

      UserSession.Classificacao.Data.Filter := '';
      UserSession.Classificacao.Data.Filtered := False;
      if TreeView.Items.Count > 1 then
        TreeView.TreeItemClick(TreeView, TreeView.Items[0]);
    finally
      TreeView.Items.EndUpdate;
    end;
  except
    on e:exception do begin
      raise exception.create('BuildHierarchy: ' + e.Message);
    end;
  end;
end;