/// <summary>
/// A version of <see cref="GetAttributes{TAttribute}(MemberInfo, AttributeSearchOptions)"/>
/// returning just one attribute.
/// </summary>
/// <typeparam name="TAttribute">The type of attribute to get.</typeparam>
/// <param name="member">Member to get attribute of.</param>
/// <param name="options">Attribute search options.</param>
/// <returns>An attribute of specified type;
/// <see langword="null"/>, if there is no such attribute;
/// throws <see cref="InvalidOperationException"/>, if there is more then one attribute of specified type found.
/// </returns>
/// <exception cref="InvalidOperationException">Thrown if there is more then one attribute of specified type found.</exception>
public static TAttribute GetAttribute <TAttribute>(this MemberInfo member, AttributeSearchOptions options = AttributeSearchOptions.InheritNone)
where TAttribute : Attribute
{
var attributes = member.GetAttributes <TAttribute>(options);
return(attributes.Count switch {
0 => null,
1 => attributes[0],
_ => throw new InvalidOperationException(string.Format(Strings.ExMultipleAttributesOfTypeXAreNotAllowedHere,
member.GetShortName(true),
typeof(TAttribute).GetShortName()))
});
/// <summary>
/// A version of <see cref="GetAttributes{TAttribute}(MemberInfo, AttributeSearchOptions)"/>
/// returning just one attribute.
/// </summary>
/// <typeparam name="TAttribute">The type of attribute to get.</typeparam>
/// <param name="member">Member to get attribute of.</param>
/// <param name="options">Attribute search options.</param>
/// <returns>An attribute of specified type;
/// <see langword="null"/>, if there is no such attribute;
/// throws <see cref="InvalidOperationException"/>, if there is more then one attribute of specified type found.
/// </returns>
/// <exception cref="InvalidOperationException">Thrown if there is more then one attribute of specified type found.</exception>
public static TAttribute GetAttribute <TAttribute>(this MemberInfo member, AttributeSearchOptions options)
where TAttribute : Attribute
{
if (options == AttributeSearchOptions.InheritNone)
{
return(member.GetAttribute <TAttribute>());
}
var attributes = member.GetAttributes <TAttribute>(options);
if (attributes.Length == 0)
{
return(null);
}
if (attributes.Length > 1)
{
throw new InvalidOperationException(string.Format(Strings.ExMultipleAttributesOfTypeXAreNotAllowedHere,
member.GetShortName(true),
typeof(TAttribute).GetShortName()));
}
return(attributes[0]);
}
/// <summary>
/// A shortcut to <see cref="MemberInfo.GetCustomAttributes(Type,bool)"/> method.
/// </summary>
/// <typeparam name="TAttribute">The type of attributes to get.</typeparam>
/// <param name="member">Member to get attributes of.</param>
/// <param name="options">Attribute search options.</param>
/// <returns>An array of attributes of specified type.</returns>
public static TAttribute[] GetAttributes <TAttribute>(this MemberInfo member, AttributeSearchOptions options)
where TAttribute : Attribute
{
if (options == AttributeSearchOptions.InheritNone)
{
return(member.GetAttributes <TAttribute>());
}
var attributes = member.GetCustomAttributes(typeof(TAttribute), false).Cast <object, TAttribute>();
if (attributes.Length == 0)
{
if ((options & AttributeSearchOptions.InheritFromPropertyOrEvent) != 0)
{
var m = member as MethodInfo;
if (m != null)
{
var poe = (MemberInfo)m.GetProperty() ?? m.GetEvent();
if (poe != null)
{
attributes = poe.GetAttributes <TAttribute>();
}
}
}
if ((options & AttributeSearchOptions.InheritFromBase) != 0 &&
(options & AttributeSearchOptions.InheritFromAllBase) == 0)
{
var bm = member.GetBaseMember();
if (bm != null)
{
attributes = attributes.Combine(bm.GetAttributes <TAttribute>(options));
}
}
}
if ((options & AttributeSearchOptions.InheritFromAllBase) != 0 &&
member.DeclaringType != WellKnownTypes.Object)
{
var bm = member.GetBaseMember();
if (bm != null)
{
attributes = attributes.Combine(bm.GetAttributes <TAttribute>(options));
}
}
return(attributes);
}
/// <summary>
/// A shortcut to <see cref="MemberInfo.GetCustomAttributes(Type,bool)"/> method.
/// </summary>
/// <typeparam name="TAttribute">The type of attributes to get.</typeparam>
/// <param name="member">Member to get attributes of.</param>
/// <param name="options">Attribute search options.</param>
/// <returns>An array of attributes of specified type.</returns>
///
public static IReadOnlyList <TAttribute> GetAttributes <TAttribute>(this MemberInfo member, AttributeSearchOptions options = AttributeSearchOptions.InheritNone)
where TAttribute : Attribute =>
AttributeDictionary <TAttribute> .Dictionary.GetOrAdd(
new PerAttributeKey(member, options),
key => GetAttributes(key.Item1, typeof(TAttribute), key.Item2).Cast <TAttribute>().ToArray()
);
