Using gps.LoadDataBase in an SelectedIndexChanged event

[tictoc]

Hi,

i do have a forms gui with a combobox to select one of a few Gps Database files in my plugin folder.

Now i want to load a new selected file when i do get the SelectedIndexChanged event, but when i try i do get an exception error:
Object reference not set to an instance of an object

I can change gui elements within this event, but i cannot use AB methods.
Looking now for hints how to fix that ...

Greetings,
tictoc

 

[Will]

Null reference exception its hard to trace without read the code. What is in your event? How do you get the db3 path?

I already did a similar code and its work:

        private Gps _gps = new Gps(core); // core is your plugin class

        private void SelectedIndexChanged(object sender, EventArgs e)
        {
            var file = ((ComboBox)sender).SelectedValue; 
            // assuming your ComboBox is filled with full path of file, if not, you need to convert to full path
            // also you can use Path.Combine(core.pluginPath, "/YourPluginFolder/" + filename);
            _gps.LoadDataBase(file);
        }

 

[tictoc]

As my SelectedIndexChanged is already similar i have concentrated on what can go wrong with:

        private Gps _gps = new Gps(core); // core is your plugin class

I had some more initialization code for the form class

        public MyPluginForm()
        {
            InitializeComponent();

            ... my additional code ...
        }

which was executed during Form initialization before core was set for this class.
After moving this additional code in the method which sets the core first, everything works fine.

Thanks,
tictoc

 

[Will]

You can also inject core in form using the constructor:

private Core _core;

public MyPluginForm(Core core)
{
      InitializeComponent();
      _core = core;
}