Frequency Display Plugin

The source code of this plugin is available here .

This plugin monitors the changes of the receive and transmit frequencies, T/R switch and Split mode, and shows these settings on a standard panel. The panel makes use of the FrequencyDisplayPanel control from the Shared Controls library.

The IPlugin.CreatePanel method creates an instance of FrequencyDisplayPanel and sets its properties:

public UserControl CreatePanel()
{
  panel = new FrequencyDisplayPanel();
  panel.Name = "Main Receiver";
  panel.bandplan = BandPlan;
  panel.pipeline = host.DspPipeline;

  return panel;
}

To receive notifications when any of the settings of interest change, the plugin subscribes to a number of events available in DSP Pipeline. To access DspPipeline, it imports the IPluginHost interface from the host application.

The MEF framework used in Ham Cockpit to manage the plugins supports several ways of importing an interface. One of them is the ImportingConstructor attribute. The constructor of the plugin, decorated with this attribute, looks like this:

[ImportingConstructor]
FrequencyDisplay([Import(typeof(IPluginHost))] IPluginHost host)
{
  this.host = host;
  host.DspPipeline.Tuner.Tuned += TunedEventHandler;
  host.DspPipeline.StatusChanged += TunedEventHandler;
  host.DspPipeline.Transmitter.Tuned += TunedEventHandler;
  host.DspPipeline.Transmitter.SettingsChanged += TunedEventHandler;
}

The same event handler is used for all events, this handler simply updates information on the display panel:

private void TunedEventHandler(object sender, EventArgs e)
{
  panel?.UpdateDisplayedInfo();
}