private void ListImportMethods_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
var item = sender as ListBoxItem;
if (item != null && item.IsSelected)
{
ImportMethod import = item.Content as ImportMethod;
import.handler.Invoke();
}
}
protected void RegisterImportMethod(ImportMethod im)
{
importMethods.Add(im);
}