LogWorkForm.cs

using System;
using System.Globalization;
using Eto.Drawing;
using Eto.Forms;

namespace devtime
{
    public class LogWorkForm : Dialog<bool>
    {
        public string Log { get; private set; } = "";
        private readonly TextArea _textArea;

        public LogWorkForm(string initialLog, string when)
        {
            Title = "Log work";
            Icon = IconLoader.LoadIcon("log.png");
            MinimumSize = new Size(268, 190);
            Resizable = true;

            _textArea = new TextArea { Text = initialLog, AcceptsTab = true, AcceptsReturn = true, Width = 232, Height = 115 };

            string suffix;
            if (DateTime.TryParseExact(when, "yyyy-MM-dd", CultureInfo.InvariantCulture, DateTimeStyles.None, out DateTime date))
            {
                if (date == DateTime.Today)
                {
                    suffix = "today";
                }
                else if (date == DateTime.Today.AddDays(-1))
                {
                    suffix = "yesterday";
                }
                else if (date == DateTime.Today.AddDays(1))
                {
                    suffix = "tomorrow";
                }
                else
                {
                    suffix = "on " + when;
                }
            }
            else
            {
                suffix = "on " + when;
            }

            var group = new GroupBox { Text = $"What did you do {suffix}?" };
            group.Content = _textArea;

            var okButton = new Button { Text = "OK" };
            okButton.Click += (sender, e) => OkClick();

            var cancelButton = new Button { Text = "Cancel" };
            cancelButton.Click += (sender, e) => Close(false);

            DefaultButton = okButton;
            AbortButton = cancelButton;

            var buttonLayout = new StackLayout
            {
                Orientation = Orientation.Horizontal,
                Spacing = 5,
                Items = { okButton, cancelButton }
            };

            Content = new TableLayout
            {
                Padding = new Padding(5),
                Spacing = new Size(3, 3),
                Rows =
                {
                    new TableRow(new TableCell(group, true)) { ScaleHeight = true },
                    new TableRow(new StackLayout { HorizontalContentAlignment = HorizontalAlignment.Right, Items = { buttonLayout } })
                }
            };
        }

        private void OkClick()
        {
            Log = _textArea.Text ?? "";
            Close(true);
        }
    }
}