Enumerations in C#

The [Flags] attribute is optional and informs the runtime that the values in the enum can be bit-combined and should be decoded accordingly in the debugger or when outputting text to console. For example:

[Flags]
internal enum Colours { Red = 1, Green = 2, Blue = 4, White = 8 };
private void Test()
{
    string [] items = System.Enum.GetNames(typeof(Colours));

    // this outputs: Red Green Blue White
    foreach (string item in items)
        textBox1.Text += item + " ";

    textBox1.Text += "\r\n";

    Colours c = Colours.Red  Colours.Blue;

    // this outputs: Red, Blue
    textBox1.Text += c + "\r\n";

    // this outputs: 5
    textBox1.Text += (int)n + "\r\n";
}