Generic 404 handler for synchronizers.

Wino.Mail.ViewModels/MailAppShellViewModel.cs

@@ -988,6 +988,21 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
         UpdateFolderCollection(mailItemFolder);
     }
 
+    protected override async void OnFolderDeleted(MailItemFolder folder)
+    {
+        base.OnFolderDeleted(folder);
+
+        bool wasSelected = SelectedMenuItem is IBaseFolderMenuItem selectedFolder &&
+            selectedFolder.HandlingFolders.Any(a => a.Id == folder.Id);
+
+        await ExecuteUIThread(() => MenuItems.RemoveFolderMenuItem(folder.Id));
+
+        if (wasSelected && latestSelectedAccountMenuItem != null)
+        {
+            await NavigateInboxAsync(latestSelectedAccountMenuItem);
+        }
+    }
+
     protected override void OnFolderSynchronizationEnabled(IMailItemFolder mailItemFolder)
     {
         base.OnFolderSynchronizationEnabled(mailItemFolder);

Wino.Mail.ViewModels/MailBaseViewModel.cs

@@ -17,6 +17,7 @@ public class MailBaseViewModel : CoreBaseViewModel,
     IRecipient<DraftFailed>,
     IRecipient<DraftMapped>,
     IRecipient<FolderRenamed>,
+    IRecipient<FolderDeleted>,
     IRecipient<FolderSynchronizationEnabled>
 {
     protected virtual void OnMailAdded(MailCopy addedMail) { }
@@ -27,6 +28,7 @@ public class MailBaseViewModel : CoreBaseViewModel,
     protected virtual void OnDraftFailed(MailCopy draftMail, MailAccount account) { }
     protected virtual void OnDraftMapped(string localDraftCopyId, string remoteDraftCopyId) { }
     protected virtual void OnFolderRenamed(IMailItemFolder mailItemFolder) { }
+    protected virtual void OnFolderDeleted(MailItemFolder folder) { }
     protected virtual void OnFolderSynchronizationEnabled(IMailItemFolder mailItemFolder) { }
 
     void IRecipient<MailAddedMessage>.Receive(MailAddedMessage message) => OnMailAdded(message.AddedMail);
@@ -39,6 +41,7 @@ public class MailBaseViewModel : CoreBaseViewModel,
     void IRecipient<DraftCreated>.Receive(DraftCreated message) => OnDraftCreated(message.DraftMail, message.Account);
 
     void IRecipient<FolderRenamed>.Receive(FolderRenamed message) => OnFolderRenamed(message.MailItemFolder);
+    void IRecipient<FolderDeleted>.Receive(FolderDeleted message) => OnFolderDeleted(message.MailItemFolder);
     void IRecipient<FolderSynchronizationEnabled>.Receive(FolderSynchronizationEnabled message) => OnFolderSynchronizationEnabled(message.MailItemFolder);
 
     protected override void RegisterRecipients()
@@ -55,6 +58,7 @@ public class MailBaseViewModel : CoreBaseViewModel,
         Messenger.Register<DraftFailed>(this);
         Messenger.Register<DraftMapped>(this);
         Messenger.Register<FolderRenamed>(this);
+        Messenger.Register<FolderDeleted>(this);
         Messenger.Register<FolderSynchronizationEnabled>(this);
     }
 
@@ -70,6 +74,7 @@ public class MailBaseViewModel : CoreBaseViewModel,
         Messenger.Unregister<DraftFailed>(this);
         Messenger.Unregister<DraftMapped>(this);
         Messenger.Unregister<FolderRenamed>(this);
+        Messenger.Unregister<FolderDeleted>(this);
         Messenger.Unregister<FolderSynchronizationEnabled>(this);
     }
 }

Wino.Mail.ViewModels/MailListPageViewModel.cs

@@ -780,6 +780,20 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         }
     }
 
+    protected override async void OnFolderDeleted(MailItemFolder folder)
+    {
+        base.OnFolderDeleted(folder);
+
+        if (ActiveFolder == null) return;
+
+        bool isActiveFolder = ActiveFolder.HandlingFolders.Any(a => a.Id == folder.Id);
+
+        if (isActiveFolder)
+        {
+            await MailCollection.ClearAsync();
+        }
+    }
+
     protected override async void OnDraftCreated(MailCopy draftMail, MailAccount account)
     {
         base.OnDraftCreated(draftMail, account);