TVCustomDrawItem (Delphi)

Description

The following example shows how the OnCustomDrawItem event handler draws items and lines of the tree view after the OnCustomDraw event handler has filled in the background.

Code

procedure TCustomDrawForm.TVCustomDrawItem(Sender: TCustomTreeView; Node: TTreeNode;
  State: TCustomDrawState; var DefaultDraw: Boolean);
var
  NodeRect: TRect;
begin
  with TV.Canvas do
  begin
{
    If DefaultDraw is True, any of the node's font 
    properties can be changed. Note also that when 
    DefaultDraw = True, Windows draws the buttons and 
    ignores your setted font background colors, using 
    instead the TreeView's Color property.
    if cdsSelected in State then
    begin
      Font.Assign(SelectedFontDialog.Font);
      Brush.Color := SelBkgColorDialog.Color;
    end;
 
    DefaultDraw := False; // FDefaultDrawItem;
{
    DefaultDraw = False means that you have to handle 
    all the item drawing yourself, including the buttons, 
    lines, images, and text.
    if not DefaultDraw then
    begin
      //Draw the selection rect.
      if cdsSelected in State then
      begin
        NodeRect := Node.DisplayRect(True);
        FillRect(NodeRect);
      end;
      NodeRect := Node.DisplayRect(False);
 
      if None1.Checked then
      //No bitmap available, so paint in the background color.
      begin
        Brush.Color := BkgColorDialog.Color;
        Brush.Style := FBrushStyle;
        FillRect(NodeRect)
      end
      else
        //Do not paint over the background bitmap.
        Brush.Style := bsClear;
 
      NodeRect.Left := NodeRect.Left + (Node.Level * TV.Indent);
      // NodeRect.Left now represents the leftmost portion 
      // of the expand button.
      DrawButton(NodeRect, Node); // See the CustomDraw demo.
 
      NodeRect.Left := NodeRect.Left + TV.Indent + FButtonSize;
      //NodeRect.Left is now the leftmost portion of the image.
      DrawImage(NodeRect, Node.ImageIndex); // See the CustomDraw demo.
 
      NodeRect.Left := NodeRect.Left + ImageList.Width;
      //Now you are finally in the position to draw the text.
 
      TextOut(NodeRect.Left, NodeRect.Top, Node.Text);
    end;
  end;
end;

Uses

• Vcl.ComCtrls.TCustomTreeView.OnCustomDrawItem ( fr | de | ja )
• Vcl.ComCtrls.TTreeNode.DisplayRect ( fr | de | ja )
• Vcl.ComCtrls.TTreeNode.Level ( fr | de | ja )
• Vcl.ComCtrls.TCustomTreeView.Indent ( fr | de | ja )