I was getting so frustrated with writing this
ViewMode viewType = (ViewMode)Enum.Parse(typeof(ViewMode), value);
all the time, so I created a class so I can do
ViewMode viewType = EnumParser.Parse<ViewMode>(value);
but the came along extension methods and now we can then do
ViewMode viewType = value.ParseEnum<ViewMode>();
then lastly wouldn't it be cool to have the default value if you can't parse it?
ViewMode viewType = value.GetEnumOrDefault<ViewMode>(ViewMode.None);
so here is the class. There is also some goodies so that you can decorate your enum's with attributes and then GetDescription to have a friendly version for them!
/// <summary>
/// Helpful helper class for all things with enumerations
/// </summary>
public static class EnumParser
{
/// <summary>
/// Parses the specified enum value - ignoring case.
/// </summary>
/// <param name="enumValue">The enum value.</param>
/// <returns></returns>
[SuppressMessage("Microsoft.Design", "CA1004:GenericMethodsShouldProvideTypeParameter")]
public static T Parse<T>(string enumValue)
{
return Parse<T>(enumValue, true);
}
/// <summary>
/// Parses the specified enum value.
/// </summary>
/// <param name="enumValue">The enum value.</param>
/// <param name="ignoreCase">if set to <c>true</c> [ignore case].</param>
/// <returns></returns>
[SuppressMessage("Microsoft.Design", "CA1004:GenericMethodsShouldProvideTypeParameter")]
public static T Parse<T>(string enumValue, bool ignoreCase)
{
if (string.IsNullOrEmpty(enumValue))
throw new ArgumentNullException("enumValue", CoreResources.NullValue);
enumValue = enumValue.Trim();
Type t = typeof(T);
if (!t.IsEnum)
throw new ArgumentException(CoreResources.InvalidType, "enumValue");
return (T)Enum.Parse(t, enumValue, ignoreCase);
}
/// <summary>
/// Parses the enum.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="value">The value.</param>
/// <returns></returns>
[SuppressMessage("Microsoft.Design", "CA1004:GenericMethodsShouldProvideTypeParameter")]
public static T ParseEnum<T>(this string value)
{
if (string.IsNullOrEmpty(value))
throw new ArgumentNullException("value", CoreResources.NullValue);
return ParseEnum<T>(value, false);
}
/// <summary>
/// Parses the enum.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="value">The value.</param>
/// <param name="ignoreCase">if set to <c>true</c> [ignore case].</param>
/// <returns></returns>
[SuppressMessage("Microsoft.Design", "CA1004:GenericMethodsShouldProvideTypeParameter")]
public static T ParseEnum<T>(this string value, bool ignoreCase)
{
if (string.IsNullOrEmpty(value))
throw new ArgumentNullException("value", CoreResources.NullValue);
return Parse<T>(value, ignoreCase);
}
/// <summary>
/// Gets the enum or default.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="value">The value.</param>
/// <param name="defaultValue">The default value.</param>
/// <returns></returns>
[SuppressMessage("Microsoft.Design", "CA1004:GenericMethodsShouldProvideTypeParameter")]
[SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes",
Justification = "Never throw the exception in this case")]
public static T GetEnumOrDefault<T>(this string value, T defaultValue)
{
if (string.IsNullOrEmpty(value))
return defaultValue;
try
{
return Parse<T>(value, true);
}
catch
{
return defaultValue;
}
}
/// <summary>
/// Tries to parse the enum. Case insensitive. Returns true/false for errors (or return InvalidArgumentException?)
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="value">The value.</param>
/// <param name="enumInstance">The enum instance.</param>
/// <returns></returns>
[SuppressMessage("Microsoft.Design", "CA1004:GenericMethodsShouldProvideTypeParameter")]
[SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes",
Justification = "Never throw the exception in this case")]
public static bool TryParseEnum<T>(this string value, out T enumInstance)
{
try
{
enumInstance = Parse<T>(value, true);
return true;
}
catch
{
enumInstance = default(T);
return false;
}
}
/// <summary>
/// Gets the <see cref="DescriptionAttribute" /> of an <see cref="Enum" />
/// type value.
/// </summary>
/// <param name="value">The <see cref="Enum" /> type value.</param>
/// <returns>A string containing the text of the
/// <see cref="DescriptionAttribute"/>.</returns>
public static string GetDescription(this Enum value)
{
if (value == null)
throw new ArgumentNullException("value", CoreResources.NullValue);
string description = value.ToString();
FieldInfo fieldInfo = value.GetType().GetField(description);
EnumDescriptionAttribute[] attributes =
(EnumDescriptionAttribute[])
fieldInfo.GetCustomAttributes(typeof(EnumDescriptionAttribute), false);
if (attributes != null && attributes.Length > 0)
{
description = attributes[0].Description;
}
return description;
}
/// <summary>
/// Converts the <see cref="Enum" /> type to an <see cref="IList" />
/// compatible object.
/// </summary>
/// <param name="type">The <see cref="Enum"/> type.</param>
/// <returns>An <see cref="IList"/> containing the enumerated
/// type value and description.</returns>
public static IList ToList(this Type type)
{
if (type == null)
throw new ArgumentNullException("type", CoreResources.InvalidType);
ArrayList list = new ArrayList();
Array enumValues = Enum.GetValues(type);
foreach (Enum value in enumValues)
{
list.Add(new KeyValuePair<Enum, string>(value, GetDescription(value)));
}
return list;
}
}
