//The constructor initialises the component, then
//sets the data context to itself and sets the FeedItem
//property accordingly.
private void MenuItem_Click(object sender, RoutedEventArgs e)
{
bool ratingValid = false;
//This variable sets up a loop in order to allow
//for a while loop to be used
while (ratingValid == false)
{
//The while loop allows for the rating input to be retried
//by the user, or cancelled if they change their mind
ratingStr = Interaction.InputBox("Please enter an importance rating from 0.0 to 10.0 to 1 decimal place" +
" (Entering nothing will cancel this operation, as will pressing the cancel button) ", "Assign rating", "");
//A VisualBasic InputBox is created and displays the following message, with a suitable title and blank
//default response. The input response is stored in a suitable variable, ratingStr, defined at the start of
//the code for this object.
if (ratingStr == "")
{
break;
}
//Pressing the cancel button on the InputBox will always return an empty string, so this if statement
//is used to detect the cancellation event and break the while loop
try
{
ratingDbl = Double.Parse(ratingStr);
}
//A try-catch block is used, and an attempt is made to parse the input string to a Double
catch (Exception)
{
MessageBox.Show("Entered rating is not a valid number, please try again or cancel", "Invalid Format", MessageBoxButton.OK);
continue;
}
//Any exception is caught here. This would be from an invalid parse, due to input of non-numeric characters.
//As such, the following dialog box alerts the user of this, and continues the while loop to allow for
//input to be retried.
ratingDbl = Math.Round(ratingDbl, 1);
//If the parsing is a success, the Double value is rounded to one decimal place
if (ratingDbl >= 0.0 && ratingDbl <= 10.0)
{
newsItem currentItem = FeedItem;
currentItem.Rating = ratingDbl;
FeedItem = currentItem;
ratingValid = true;
}
//If the rating input is between the boundaries of 0 and 10 inclusive, then the rating of the
//newsItem object contained in the TickerItemEelement object is set to this input rating value
//by first retrieving the stored newsItem, setting the rating value, and then storing the altered
//newsItem
//ratingValid is thereafter set to true, breaking the while loop.
else
{
MessageBox.Show("Entered rating is not between 0.0 and 10.0, please try again", "Invalid Range", MessageBoxButton.OK);
continue;
}
//If the rating value is outside of these boundaries, the following is displayed, and the
//while loop continues to allow the user to retry inputting the rating
}
if (ratingStr == "")
{
}
//If the input was cancelled then the while loop breaks, and so to stop
//the addition of an unwanted item to the watchLater database, this if statement
//detects that eventuality and ensures that no action is taken
else
{
DataRoutines.addItem(this);
}
//If the if statement above is not triggered, then the TickerItemElement object
//is added to the database using the DataRoutines function addItem.
}
