Clipboard action now sets an expiration timer

WIP Max History count (back-end done, front-end todo)

ModernKeePass.Application/Parameters/Commands/SetMaxHistoryCount/SetHistoryCountCommand.cs

@@ -0,0 +1,27 @@
+using MediatR;
+using ModernKeePass.Application.Common.Interfaces;
+using ModernKeePass.Domain.Exceptions;
+
+namespace ModernKeePass.Application.Parameters.Commands.SetMaxHistoryCount
+{
+    public class SetMaxHistoryCountCommand : IRequest
+    {
+        public int MaxHistoryCount { get; set; }
+
+        public class SetMaxHistoryCountCommandHandler : IRequestHandler<SetMaxHistoryCountCommand>
+        {
+            private readonly IDatabaseProxy _database;
+
+            public SetMaxHistoryCountCommandHandler(IDatabaseProxy database)
+            {
+                _database = database;
+            }
+
+            public void Handle(SetMaxHistoryCountCommand message)
+            {
+                if (_database.IsOpen) _database.MaxHistoryCount = message.MaxHistoryCount;
+                else throw new DatabaseClosedException();
+            }
+        }
+    }
+}