//////////////////////////////////////////////////
///
/// <author>Nicholas Paldino</author>
/// <created>2013-10-22</created>
/// <summary>Gets the <see cref="EnumCodeAttribute.Code"/>
/// property given a value from an enumeration.</summary>
/// <typeparam name="T">The type of the enumeration
/// to get the <see cref="EnumCodeAttribute"/>
/// from.</typeparam>
/// <param name="value">The value from the enumeration type
/// <typeparamref name="T"/> to get the attribute for.</param>
/// <returns>The <see cref="EnumCodeAttribute.Code"/> or null
/// if there is none.</returns>
///
//////////////////////////////////////////////////
public static string GetEnumCodeAttributeCode <T>(T value) where T : struct
{
// Get the attribute.
EnumCodeAttribute attribute = GetEnumCodeAttribute(value);
// If it is null, return null, otherwise,
// return the code.
return(attribute?.Code);
}
//////////////////////////////////////////////////
///
/// <author>Nicholas Paldino</author>
/// <created>2012-07-28</created>
/// <summary>Sets up the <see cref="IDictionary{TKey,TValue}"/>
/// that maps the code to the <typeparamref name="T"/>.</summary>
/// <typeparam name="T">The enumeration type.</typeparam>
/// <returns>The <see cref="IDictionary{TKey,TValue}"/>
/// that is the map between the code and the
/// enumeration value.</returns>
///
//////////////////////////////////////////////////
private static IDictionary <string, T> SetupTryGetByEnumCodeMap <T>(bool ignoreCase) where T : struct
{
// Get the type.
Type t = typeof(T);
// The type is an enumeration.
Debug.Assert(t.GetTypeInfo().IsEnum);
// Create the lookup.
IDictionary <string, T> lookup = new Dictionary <string, T>(ignoreCase ? StringComparer.OrdinalIgnoreCase : StringComparer.Ordinal);
// Cycle through all of the fields.
foreach (KeyValuePair <T, FieldInfo> pair in GetEnumFieldsDictionary <T>())
{
// Get the field info.
FieldInfo fi = pair.Value;
// The declaring type is not null.
Debug.Assert(fi.DeclaringType != null);
// If the attribute does not exist on the type, then throw
// an exception.
EnumCodeAttribute attribute = pair.Value.GetCustomAttributes <EnumCodeAttribute>(true).SingleOrDefault();
// If the attribute is null, throw an exception.
if (attribute == null)
{
throw new InvalidOperationException(
string.Format(CultureInfo.InvariantCulture, "The {0} value in the {1} enumeration does not have the EnumCodeAttribute applied to it.",
fi.Name, fi.DeclaringType.FullName));
}
// The looked up value.
T value;
// Try and look up, it should not succeed.
if (lookup.TryGetValue(attribute.Code, out value))
{
// Throw an exception.
throw new InvalidOperationException(
string.Format(CultureInfo.InvariantCulture, "The code \"{0}\" is already applied to another value in the {1} enumeration.",
attribute.Code, fi.DeclaringType.FullName));
}
// Add the value.
lookup.Add(attribute.Code, pair.Key);
}
// Return the lookup.
return(lookup);
}