Add CanRun property to Formatter.

zaaReloaded2/Formatter/Formatter.cs

@@ -64,6 +64,12 @@ namespace zaaReloaded2.Formatter
         /// </summary>
         public Dictionary<DateTime, TimePointFormatter> WorkingTimePoints { get; private set; }
 
+        /// <summary>
+        /// Is true if this Formatter object carries a Laboratory with
+        /// at least one time point.
+        /// </summary>
+        public bool CanRun { get { return Laboratory.TimePoints.Count > 0; } }
+
         #endregion
 
         #region Constructors
@@ -113,6 +119,8 @@ namespace zaaReloaded2.Formatter
         /// current position of the cursor).</param>
         public void Run()
         {
+            if (!CanRun) throw new InvalidOperationException("No laboratory data to format.");
+
             int current = 0;
             while (current < Settings.Elements.Count)
             {