protected void Submit_Click(object sender, EventArgs e)
 {
     Debug.WriteLine("Submit_Click");
     Debug.WriteLine($"FilterField: {SelectedFilter}");
     for (var i = 1; i <= 5; i++)
     {
         var textBox = (TextBox)DataPanel.FindControl($"Name-{i}");
         if (textBox == null)
         {
             continue;
         }
         var name = textBox.Text;
         Debug.WriteLine($"Group {i} - Name:{name}");
     }
 }
        protected void FilterButton_Click(object sender, EventArgs e)
        {
            var button = (Button)sender;

            if (button == null)
            {
                return;
            }

            var filter = button.Attributes["data-filter"];

            SelectedFilter = int.Parse(filter);

            var parentControl = DataPanel.FindControl($"Name-{filter}").Parent;

            parentControl.Visible = !parentControl.Visible;

            Debug.WriteLine($"Filter = {filter}");
        }