implemented teardown of all tabs when closing Main App

MultiTerm.Core/ViewModel/ITerminalViewModel.cs

@@ -36,6 +36,12 @@ public interface ITerminalViewModel
     /// </summary>
     void CloseRequest();
 
+    /// <summary>
+    /// Force close the Terminal and disconnect communication protocol.
+    /// Does not raise <see cref="ClosingEvent"/>.
+    /// </summary>
+    void ForceClose();
+
     /// <summary>
     /// Closing of Terminal was initiated.
     /// </summary>

MultiTerm.Core/ViewModel/ShellViewModel.cs

@@ -68,6 +68,20 @@ public partial class ShellViewModel : ObservableObject, IRecipient<IUserInterfac
         this.AppendTerminalWithSelectedViewType(ProtocolType.Serial);
     }
 
+    /// <summary>
+    /// Forcefully close all <see cref="TerminalViewModel"/>s.
+    /// </summary>
+    public void Teardown()
+    {
+        // iterate through all terminals
+        foreach (ITerminalViewModel terminal in this.TerminalViewModels)
+        {
+            // forcefully close
+            terminal.ForceClose();
+            // do not remove from collection, otherwise the collection was changed
+        }
+    }
+
     [RelayCommand]
     private void AppendTerminalWithSelectedViewType(ProtocolType protocolType)
     {
@@ -75,7 +89,6 @@ public partial class ShellViewModel : ObservableObject, IRecipient<IUserInterfac
         this.AppendConfiguredTerminal(this.terminalViewModelFactory.Create(this.SelectedTerminalViewType, protocolType));
     }
 
-
     private void AppendConfiguredTerminal(ITerminalViewModel? newTerminal)
     {
         // guard null value

MultiTerm.Core/ViewModel/TerminalViewModel.cs

@@ -9,7 +9,6 @@ using MultiTerm.Core.Types;
 using MultiTerm.Protocols;
 using MultiTerm.Protocols.Model;
 using MultiTerm.Protocols.Types;
-using System.Text;
 
 namespace MultiTerm.Core.ViewModel;
 
@@ -104,8 +103,12 @@ public abstract partial class TerminalViewModel : ObservableObject, ITerminalVie
     {
         if (this.CommunicationProtocol != null)
         {
+            // disconnect communication protocol
+            this.OnViewModelRequestedDisconnect(this, EventArgs.Empty);
+            // unsubscribe events
             this.CommunicationProtocol.ReceivedDataEvent -= CommunicationProtocol_ReceivedDataEvent;
             this.CommunicationProtocol.SentDataEvent -= CommunicationProtocol_SentDataEvent;
+            // remove reference to object
             this.CommunicationProtocol = null;
         }
     }
@@ -230,11 +233,24 @@ public abstract partial class TerminalViewModel : ObservableObject, ITerminalVie
     [RelayCommand]
     public void CloseRequest()
     {
+        // run internal closing actions check if closing is allowed
         if (this.ClosingActions() == true)
         {
+            // disconnect communication protocol
+            this.OnViewModelRequestedDisconnect(this, EventArgs.Empty);
+            // raise event
             ClosingEvent?.Invoke(this, EventArgs.Empty);
         }
     }
+
+    public void ForceClose()
+    {
+        // internal closing options, ignore cancellation
+        this.ClosingActions(); 
+        // disconnect communication protocol
+        this.OnViewModelRequestedDisconnect(this, EventArgs.Empty);
+        // do not raise closing event, since caller knows about closing
+    }
     #endregion
 
     #region Newline Separator handling

MultiTerm.Wpf/App.xaml.cs

@@ -78,6 +78,10 @@ public partial class App : Application
         var appSettingsProvider = AppHost!.Services.GetRequiredService<IAppSettingsProvider>();
         appSettingsProvider.Save();
 
+        // teardown of terminal views and communication protocol threads
+        var shellViewModel = AppHost!.Services.GetRequiredService<ShellViewModel>();
+        shellViewModel.Teardown();
+
         // log application exit and stop logger (if still available)
         logger?.LogInfo("Application exited.", nameof(App));
         logger?.StopLogging();