Issue #100: implemented functions GetLastError, ResetLastError() in MtApi (MT5)

TestClients/MtApi5TestClient/ViewModel.cs

@@ -60,6 +60,8 @@ namespace MtApi5TestClient
 
         public DelegateCommand PositionOpenCommand { get; private set; }
 
+        public DelegateCommand GetLastErrorCommand { get; private set; }
+        public DelegateCommand ResetLastErrorCommand { get; private set; }
         public DelegateCommand PrintCommand { get; private set; }
 
         public DelegateCommand iCustomCommand { get; private set; }
@@ -257,6 +259,8 @@ namespace MtApi5TestClient
             PositionOpenCommand = new DelegateCommand(ExecutePositionOpen);
 
             PrintCommand = new DelegateCommand(ExecutePrint);
+            GetLastErrorCommand = new DelegateCommand(ExecuteGetLastError);
+            ResetLastErrorCommand = new DelegateCommand(ExecuteResetLastError);
 
             iCustomCommand = new DelegateCommand(ExecuteICustom);
 
@@ -926,6 +930,18 @@ namespace MtApi5TestClient
             AddLog($"Print: message print in MetaTrader - {retVal}");
         }
 
+        private async void ExecuteGetLastError(object obj)
+        {
+            var retVal = await Execute(() => _mtApiClient.GetLastError());
+            AddLog($"GetLastError: last error = {retVal}");
+        }
+
+        private void ExecuteResetLastError(object obj)
+        {
+            _mtApiClient.ResetLastError();
+            AddLog("GetLastError: executed.");
+        }
+
         private async void ExecuteICustom(object o)
         {
             const string symbol = "EURUSD";