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Added FindElementType extension method for Type.

pull/60/head
David Hall 2019-03-25 17:34:43 -07:00
parent 43a453fef9
commit f64c2b5e6b
1 changed files with 27 additions and 0 deletions
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27
Core/Extensions/ReflectionExtensions.cs
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@ -32,6 +32,33 @@ namespace Vanara.Extensions
public static IEnumerable<TAttr> GetCustomAttributes<TAttr>(this Type type, bool inherit = false, Func<TAttr, bool> predicate = null) where TAttr : Attribute =>
type.GetCustomAttributes(typeof(TAttr), inherit).Cast<TAttr>().Where(predicate ?? (a => true));
/// <summary>Finds the type of the element of a type. Returns null if this type does not enumerate.</summary>
/// <param name="type">The type to check.</param>
/// <returns>The element type, if found; otherwise, <see langword="null"/>.</returns>
public static Type FindElementType(this Type type)
{
if (type.IsArray)
return type.GetElementType();
// type is IEnumerable<T>;
if (ImplIEnumT(type))
return type.GetGenericArguments().First();
// type implements/extends IEnumerable<T>;
var enumType = type.GetInterfaces().Where(ImplIEnumT).Select(t => t.GetGenericArguments().First()).FirstOrDefault();
if (enumType != null)
return enumType;
// type is IEnumerable
if (IsIEnum(type) || type.GetInterfaces().Any(IsIEnum))
return typeof(object);
return null;
bool IsIEnum(Type t) => t == typeof(System.Collections.IEnumerable);
bool ImplIEnumT(Type t) => t.IsGenericType && t.GetGenericTypeDefinition() == typeof(IEnumerable<>);
}
/// <summary>Gets a named property value from an object.</summary>
/// <typeparam name="T">The expected type of the property to be returned.</typeparam>
/// <param name="obj">The object from which to retrieve the property.</param>