New WinoListView implementation with multiple selections.

Wino.Mail.ViewModels/Data/IMailListItem.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Collections.Generic;
+using System.ComponentModel;
 using Wino.Core.Domain.Interfaces;
 
 namespace Wino.Mail.ViewModels.Data;
@@ -7,7 +9,7 @@ namespace Wino.Mail.ViewModels.Data;
 /// Common interface for mail items that can be displayed in a mail list.
 /// Implemented by both MailItemViewModel and ThreadMailItemViewModel.
 /// </summary>
-public interface IMailListItem : IMailHashContainer
+public interface IMailListItem : IMailHashContainer, INotifyPropertyChanged
 {
     /// <summary>
     /// Gets the latest creation date for sorting purposes.
@@ -22,4 +24,18 @@ public interface IMailListItem : IMailHashContainer
     /// For ThreadMailItemViewModel: the latest email's from name
     /// </summary>
     string FromName { get; }
+
+    /// <summary>
+    /// Gets whether this item is selected.
+    /// For MailItemViewModel: returns IsSelected
+    /// For ThreadMailItemViewModel: returns IsSelected
+    /// </summary>
+    bool IsSelected { get; set; }
+
+    /// <summary>
+    /// Gets all selected mail items within this list item.
+    /// For MailItemViewModel: returns itself if IsSelected is true, otherwise empty
+    /// For ThreadMailItemViewModel: returns all selected emails within the thread
+    /// </summary>
+    IEnumerable<MailItemViewModel> GetSelectedMailItems();
 }