MUDEngine:

* Door.cs - Now contains a TravelDirection property so rooms can find what travel direction each doorway within uses.
 * Room - Now contains a collection for Installed Doors
 * TravelDirections.cs - Now contains a 'None' enumerable value.

Room Designer:
 * Did some additional work on implementing Installed Doors and handling their changing Installed/Uninstalled values.

MUDEngine/Objects/Environment/Door.cs

@@ -46,5 +46,12 @@ namespace MUDEngine.Objects.Environment
             get;
             set;
         }
+
+        [Browsable(false)]
+        public AvailableTravelDirections TravelDirection
+        {
+            get;
+            set;
+        }
     }
 }

MUDEngine/Objects/Environment/Room.cs

@@ -56,10 +56,15 @@ namespace MUDEngine.Objects.Environment
 
         public Room()
         {
+            InstalledDoors = new List<Door>();
+
             this.Feel = "You feel nothing.";
             this.Listen = "You hear nothing of interest.";
             this.Smell = "You don't smell anything unsual.";
             this.StatDrainAmount = 0;
         }
+
+        [Browsable(false)]
+        public List<Door> InstalledDoors;
     }
 }

MUDEngine/Objects/Environment/TravelDirections.cs

@@ -2,11 +2,12 @@
 {
     public enum AvailableTravelDirections
     {
+        None = 0,
         North,
         South,
         East,
         West,
         Up,
-        Down
+        Down,
     }
 }

RoomDesigner/frmMain.Designer.cs

@@ -284,6 +284,7 @@
             this.propertyDoor.Name = "propertyDoor";
             this.propertyDoor.Size = new System.Drawing.Size(350, 183);
             this.propertyDoor.TabIndex = 4;
+            this.propertyDoor.PropertyValueChanged += new System.Windows.Forms.PropertyValueChangedEventHandler(this.propertyDoor_PropertyValueChanged);
             // 
             // groupBox6
             // 

RoomDesigner/frmMain.cs

@@ -32,6 +32,7 @@ namespace RoomDesigner
             foreach (int Value in Values)
             {
                 string Display = Enum.GetName(type.GetType(), Value);
+                if (Display != "None")
                     this.lstDirections.Items.Add(Display);
             }
 
@@ -44,7 +45,58 @@ namespace RoomDesigner
 
         private void lstDirections_SelectedIndexChanged(object sender, EventArgs e)
         {
+            bool IsFound = false;
+
+            foreach (Door newDoor in room.InstalledDoors)
+            {
+                if (newDoor.TravelDirection.ToString() == lstDirections.SelectedItem.ToString())
+                {
+                    door = newDoor;
+                    IsFound = true;
+                    break;
+                }
+            }
+
+            if (!IsFound)
+                door = new Door();
+
             propertyDoor.SelectedObject = door;
         }
+
+        private void propertyDoor_PropertyValueChanged(object s, PropertyValueChangedEventArgs e)
+        {
+            if (door.DoorState == Door.AvailableDoorStates.Installed)
+            {
+                foreach(Door newDoor in room.InstalledDoors)
+                {
+                    if (newDoor.TravelDirection == door.TravelDirection)
+                    {
+                        DialogResult result = MessageBox.Show("Door already exists! Overwrite it?", "Room Designer", MessageBoxButtons.YesNo);
+                        if (result == DialogResult.No)
+                            return;
+
+                        room.InstalledDoors.Remove(newDoor);
+                        room.InstalledDoors.Add(door);
+                        break;
+                    }
+                    else
+                    {
+                        room.InstalledDoors.Add(door);
+                    }
+                }
+                //Incase there are no existing doors, the foreach loop gets skipped.
+                if (room.InstalledDoors.Count == 0)
+                {/*
+                    foreach (Enum e in door.TravelDirection)
+                    {
+                        if (e.ToString() == lstDirections.SelectedItem.ToString())
+                        {
+                            door.TravelDirection = e;
+                        }
+                    }
+                  */
+                }
+            }
+        }
     }
 }