restore temperature unit menu, closes #9

Author: sergiye

OpenHardwareMonitor/UI/MainForm.Designer.cs

@@ -250,6 +250,10 @@ public MainForm()
                 _gadget.Visible = _showGadget.Value;
         };
 
+        UnitManager.IsFahrenheitUsed = _settings.GetValue("TemperatureInFahrenheit", UnitManager.IsFahrenheitUsed);
+        fahrenheitMenuItem.Checked = UnitManager.IsFahrenheitUsed;
+        celsiusMenuItem.Checked= !fahrenheitMenuItem.Checked;
+
         Server = new HttpServer(_root,
                                 _settings.GetValue("listenerIp", "?"),
                                 _settings.GetValue("listenerPort", 8085),
@@ -921,6 +925,20 @@ private void TreeView_NodeMouseDoubleClick(object sender, TreeNodeAdvMouseEventA
             ShowParameterForm(node.Sensor);
     }
 
+    private void CelsiusMenuItem_Click(object sender, EventArgs e)
+    {
+        celsiusMenuItem.Checked = true;
+        UnitManager.IsFahrenheitUsed = fahrenheitMenuItem.Checked = false;
+        _settings.SetValue("TemperatureInFahrenheit", UnitManager.IsFahrenheitUsed);
+    }
+
+    private void FahrenheitMenuItem_Click(object sender, EventArgs e)
+    {
+        celsiusMenuItem.Checked = false;
+        UnitManager.IsFahrenheitUsed = fahrenheitMenuItem.Checked = true;
+        _settings.SetValue("TemperatureInFahrenheit", UnitManager.IsFahrenheitUsed);
+    }
+
     private void ResetMinMaxMenuItem_Click(object sender, EventArgs e)
     {
         _computer.Accept(new SensorVisitor(delegate(ISensor sensorClick)

OpenHardwareMonitor/UI/MainForm.cs

@@ -2,7 +2,7 @@
 
 public static class UnitManager
 {
-    public static bool IsFahrenheitUsed => !OperatingSystemHelper.IsMetricSystemUsed;
+    public static bool IsFahrenheitUsed { get; set; } = !OperatingSystemHelper.IsMetricSystemUsed;
 
     public static float? CelsiusToFahrenheit(float? valueInCelsius)
     {