[#44] BaseDataWindow: Add button to add/delete seasons

Elwig/Dialogs/NewSeasonDialog.xaml.cs

@@ -0,0 +1,30 @@
+using Elwig.Helpers;
+using Elwig.Models.Entities;
+using System.Collections.Generic;
+using System.Windows;
+
+namespace Elwig.Dialogs {
+    public partial class NewSeasonDialog : Window {
+
+        public IEnumerable<Currency> Currencies { get; set; }
+        public int Year { get; set; }
+
+        public string CurrencyCode => (CurrencyInput.SelectedItem as Currency)!.Code;
+        public byte Precision => (byte)(PrecisionInput.SelectedIndex + 2);
+        public bool CopyModifiers { get; set; }
+
+        public NewSeasonDialog(Season? s, IEnumerable<Currency> currencies) {
+            Currencies = currencies;
+            CopyModifiers = s != null;
+            InitializeComponent();
+            CopyModifiersInput.IsEnabled = s != null;
+            ControlUtils.SelectItemWithPk(CurrencyInput, s?.CurrencyCode ?? "EUR");
+            PrecisionInput.SelectedIndex = (s?.Precision ?? 4) - 2;
+        }
+
+        private void ConfirmButton_Click(object sender, RoutedEventArgs evt) {
+            DialogResult = true;
+            Close();
+        }
+    }
+}