/// <summary>
/// "Factory" method that creates a WidgetCollection object from
/// the contents of the specified file.
/// </summary>
/// <param name="path">Path and filename of a comma separated value (CSV) file
/// from which to read data for creating Widget objects.</param>
/// <returns>A collection of Widget objects.</returns>
public static WidgetCollection CreateFromCSVFile(string path)
{
if (!File.Exists(path))
{
return(null);
}
WidgetCollection result = new WidgetCollection();
StreamReader reader;
try
{
// Open the file.
reader = new StreamReader(path);
// For each line from the file, create a Widget object and
// add it to the result collection.
string line;
while ((line = reader.ReadLine()) != null)
{
Widget widget = Widget.CreateFromCSV(line);
if (widget != null)
{
// Result is a WidgetCollection object, which has an
// Add method inherited from List<>.
result.Add(widget);
}
}
// Don't forget to close the file!
reader.Close();
}
catch (Exception)
{
return(null);
}
return(result);
}
static void Main(string[] args)
{
string dataPath = "..\\..\\Widgets.csv";
if (!File.Exists(dataPath))
{
Console.WriteLine("Make sure Widgets.csv is in the project's base path.");
}
else
{
WidgetCollection widgets = WidgetCollection.CreateFromCSVFile(dataPath);
if (widgets == null)
{
Console.WriteLine("Problem reading file.");
}
else
{
widgets.PrintSummary();
}
}
}
