Fix: clear dgvBluetoothDevices.

BITable/BiTable.cs

@@ -2,12 +2,10 @@
 using System.Data;
 using System.Linq;
 using System.Windows.Forms;
-
 using InTheHand.Net.Bluetooth;
 using InTheHand.Net.Sockets;
 using System.IO;
 using System.Threading.Tasks;
-using System.Drawing.Printing;
 using Newtonsoft.Json;
 using System.Drawing;
 
@@ -29,6 +27,11 @@ namespace BITable
 
         private void ScanBluetoothDevices()
         {
+            dgvBluetoothDevices.Invoke(new Action(() =>
+            {
+                dgvBluetoothDevices.Rows.Clear();
+            }));
+
             devices = client.DiscoverDevices();
             foreach (var device in devices)
             {
@@ -44,8 +47,18 @@ namespace BITable
         {
             Task.Factory.StartNew(new Action(() =>
             {
+                btnScanBluetoothDevices.Invoke(new Action(() =>
+                {
+                    btnScanBluetoothDevices.Enabled = false;
+                }));
                 ScanBluetoothDevices();
-            }));
+            })).ContinueWith(t =>
+            {
+                btnScanBluetoothDevices.Invoke(new Action(() =>
+                {
+                    btnScanBluetoothDevices.Enabled = true;
+                }));
+            });
         }
 
         private void dgvBluetoothDevices_CellMouseDoubleClick(object sender, DataGridViewCellMouseEventArgs e)