prs/prs.mobile.new/PRS.Mobile/CustomControls/StringList.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using Xamarin.Forms;
using Xamarin.Forms.Xaml;

namespace PRS.Mobile
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class StringList : ContentView
    {
        private List<DeleteableEditor> _editors = new List<DeleteableEditor>();
        private ImageButton _add;
        public StringList()
        {
            InitializeComponent();
            _add = _addbutton;
        }

        private void AddBtn_Clicked(object sender, EventArgs e)
        {
            _editors.Add(CreateEditor());
            LoadLayout();
        }

        private void LoadLayout()
        {
            _grid.Children.Clear();
            _grid.RowDefinitions.Clear();
            foreach (var editor in _editors)
            {
                _grid.RowDefinitions.Add(new RowDefinition() { Height = GridLength.Auto } );
                editor.SetValue(Grid.RowProperty,_grid.RowDefinitions.Count-1);
                _grid.Children.Add(editor);
            }
            if (!_editors.Any())
                _grid.RowDefinitions.Add(new RowDefinition() { Height = GridLength.Auto } );
            _add.SetValue(Grid.RowProperty, _grid.RowDefinitions.Count-1);
            _add.SetValue(Grid.ColumnProperty, 1);
            _grid.Children.Add(_add);
        }

        private DeleteableEditor CreateEditor(string text = "")
        {
            DeleteableEditor editor = new DeleteableEditor(text);
            editor.OnEditorDeleted += () =>
            {
                _editors.Remove(editor); 
                if (!_editors.Any())
                    _editors.Add(CreateEditor());
                LoadLayout();
            };
            return editor;
        }

        public void LoadList(string[] items)
        {
            _editors.Clear();
            foreach (var item in items)
                _editors.Add(CreateEditor(item));
            LoadLayout();
        }

        public string[] SaveItems()
        {
            List<string> items = new List<string>();
            foreach (DeleteableEditor entry in _editors)
            {
                if (!string.IsNullOrEmpty(entry.Text))
                    items.Add(entry.Text);
            }
            return items.ToArray();
        }
    }

    public delegate void EditorDeleted();

    public class DeleteableEditor : Grid
    {
        public event EditorDeleted OnEditorDeleted;
        public string Text { get; set; }
        public DeleteableEditor(string text = "")
        {
            Text = text;
            Setup();
        }

        private void Setup()
        {
            ColumnSpacing = 0;
            ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(1, GridUnitType.Auto) });
            ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(1, GridUnitType.Star) });

            ImageButton img = new ImageButton
            {
                Source = "cross",
                HeightRequest = 30,
                WidthRequest = 30
            };
            img.Clicked += (o,e) => OnEditorDeleted?.Invoke();
            Grid.SetColumn(img, 0);

            var edt = new Entry
            {
                Text = Text,
                FontSize = 16,
                Keyboard = Keyboard.Plain,
                BackgroundColor = Color.LightYellow,
                TextColor = Color.Black
            };
            edt.TextChanged += (sender, e) =>
            {
                Text = edt.Text;
            };
            Grid.SetColumn(edt, 1);
            
            Children.Add(edt);
            Children.Add(img);
        }
        
    }
}