Add project files.

GpsTestApp/Extensions.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace GpsTestApp {
+    public static class Extensions {
+        public static void InvokeIfRequired(this Control c, Action a) {
+            if (c.InvokeRequired) {
+                c.Invoke(new MethodInvoker(() => { InvokeIfRequired(c, a); }));
+                return;
+            }
+            try {
+                if (!c.IsHandleCreated) { IntPtr i = c.Handle; }    // See links above - handle is not created, will cause cross-thread exceptions
+                a.Invoke();
+            } catch (Exception ex) { }
+        }
+    }
+}