adding discovery menu

MainForm.cs

@@ -15,6 +15,8 @@ namespace robospot_camera_finder
         public static string cam_username = "admin";
         public static string cam_password = "RoboSpot10";
 
+        private static string browse_scope = "_rtsp._tcp";
+
         public class Camera
         {
             private IPAddress ip;
@@ -93,8 +95,6 @@ namespace robospot_camera_finder
                 }
             }
 
-            browser.StartBrowse("_rtsp._tcp");
-
             lbMain.DataSource = all_cameras;
             lbMain.DisplayMember = "camera_name";
             lbMain.ValueMember = "camera_ip";
@@ -111,8 +111,34 @@ namespace robospot_camera_finder
 
             browser.ServiceRemoved += (sender, args) =>
             {
-                ServiceRemoved(sender, args);
+                if (browser.IsBrowsing)
+                {
+                    ServiceRemoved(sender, args);
+                }
             };
+
+            browse(true);
+        }
+
+        private void browse(bool browse_needed)
+        {
+            if (browse_needed)
+            {
+                if (!browser.IsBrowsing)
+                {
+                    browser.StartBrowse(browse_scope);
+                }
+            }
+            else
+            {
+                if (browser.IsBrowsing)
+                {
+                    browser.StopBrowse();
+                }
+            }
+
+            startToolStripMenuItem.Enabled = !browser.IsBrowsing;
+            stopToolStripMenuItem.Enabled = browser.IsBrowsing;
         }
 
         private void ServiceAdded(object sender, ServiceAnnouncementEventArgs args)
@@ -140,8 +166,25 @@ namespace robospot_camera_finder
                         serial = serial_line.Substring("SerialNumber=".Length).Trim();
                     }
 
-                    Camera camera = new Camera("Camera " + cam_addr.ToString() + " - " + location + " - " + serial, cam_addr, location, serial);
-                    all_cameras.Add(camera);
+                    Camera new_camera = new Camera("Camera " + cam_addr.ToString() + " - " + location + " - " + serial, cam_addr, location, serial);
+
+                    if (all_cameras.Count == 0)
+                    {
+                        all_cameras.Add(new_camera);
+                    } else
+                    {
+                        for (int i = 0; i < all_cameras.Count; i++)
+                        {
+                            if (all_cameras[i].camera_serial == new_camera.camera_serial)
+                            {
+                                all_cameras[i] = new_camera;
+                            }
+                            else
+                            {
+                                all_cameras.Add(new_camera);
+                            }
+                        }
+                    }
                 }
             }
         }
@@ -180,5 +223,26 @@ namespace robospot_camera_finder
                 toolStripStatusLabel.Text = "";
             }
         }
+
+        private void startToolStripMenuItem_Click(object sender, EventArgs e)
+        {
+            browse(true);
+        }
+
+        private void stopToolStripMenuItem_Click(object sender, EventArgs e)
+        {
+            browse(false);
+        }
+
+        private void forceReloadToolStripMenuItem_Click(object sender, EventArgs e)
+        {
+            DialogResult result = MessageBox.Show("Are you sure you want to clear discovered cameras and restart the discovery process ?", "Warning", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
+            if (result == DialogResult.Yes)
+            {
+                browse(false);
+                all_cameras.Clear();
+                browse(true);
+            }
+        }
     }
 }