我有一个泛型类在我的项目与派生类。
public class GenericClass<T> : GenericInterface<T>
{
}
public class Test : GenericClass<SomeType>
{
}
是否有任何方法可以查明Type对象是否派生自GenericClass?
t.IsSubclassOf(typeof(GenericClass<>))
不管用。
我有一个泛型类在我的项目与派生类。
public class GenericClass<T> : GenericInterface<T>
{
}
public class Test : GenericClass<SomeType>
{
}
是否有任何方法可以查明Type对象是否派生自GenericClass?
t.IsSubclassOf(typeof(GenericClass<>))
不管用。
当前回答
下面是我创建的一个小方法,用于检查对象是否派生于特定类型。对我来说太棒了!
internal static bool IsDerivativeOf(this Type t, Type typeToCompare)
{
if (t == null) throw new NullReferenceException();
if (t.BaseType == null) return false;
if (t.BaseType == typeToCompare) return true;
else return t.BaseType.IsDerivativeOf(typeToCompare);
}
其他回答
试试这段代码
static bool IsSubclassOfRawGeneric(Type generic, Type toCheck) {
while (toCheck != null && toCheck != typeof(object)) {
var cur = toCheck.IsGenericType ? toCheck.GetGenericTypeDefinition() : toCheck;
if (generic == cur) {
return true;
}
toCheck = toCheck.BaseType;
}
return false;
}
你可以试试这个扩展
public static bool IsSubClassOfGenericClass(this Type type, Type genericClass,Type t)
{
return type.IsSubclassOf(genericClass.MakeGenericType(new[] { t }));
}
更新后的答案
这个方法检查typeA是否等于、继承(class: class)、实现(class: interface)或扩展(interface: interface) typeB。它接受泛型和非泛型接口和类。
public static bool Satisfies(Type typeA, Type typeB)
{
var types = new List<Type>(typeA.GetInterfaces());
for (var t = typeA; t != null; t = t.BaseType)
{
types.Add(t);
}
return types.Any(t =>
t == typeB ||
t.IsGenericType && (t.GetGenericTypeDefinition() == typeB));
}
在下面使用,它通过了76个测试中的74个@Xav987的答案(它没有通过测试'68-3'和'69-3',但我认为这些测试暗示List<长颈鹿>是List<动物>的子类,我不认为它是。例如,List<长颈鹿>不能施放到List<动物>,参见https://stackoverflow.com/a/9891849/53252。)
public static bool IsSubClassOfGeneric(this Type typeA, Type typeB)
{
if (typeA == typeB)
{
return false;
}
return Satisfies(typeA, typeB);
}
例子:
using System.Collections;
using System.Numerics;
void ShowSatisfaction(Type typeA, Type typeB)
{
var satisfied = Satisfies(typeA, typeB);
Console.WriteLine($"{satisfied}: [{typeA}] satisfies [{typeB}]");
}
ShowSatisfaction(typeof(object), typeof(string));
ShowSatisfaction(typeof(string), typeof(object));
ShowSatisfaction(typeof(string), typeof(IEnumerable));
ShowSatisfaction(typeof(string), typeof(IEnumerable<>));
ShowSatisfaction(typeof(string), typeof(IEnumerable<char>));
ShowSatisfaction(typeof(string), typeof(IEnumerable<int>));
ShowSatisfaction(typeof(int), typeof(object));
ShowSatisfaction(typeof(int), typeof(IComparable));
ShowSatisfaction(typeof(IReadOnlyDictionary<,>), typeof(IReadOnlyCollection<>));
ShowSatisfaction(typeof(bool), typeof(INumber<>));
ShowSatisfaction(typeof(int), typeof(INumber<>));
ShowSatisfaction(typeof(IBinaryInteger<>), typeof(IShiftOperators<,>));
ShowSatisfaction(typeof(IBinaryInteger<int>), typeof(IShiftOperators<,>));
ShowSatisfaction(typeof(IBinaryInteger<int>), typeof(IShiftOperators<int, int>));
输出:
False: [System.Object] satisfies [System.String]
True: [System.String] satisfies [System.Object]
True: [System.String] satisfies [System.Collections.IEnumerable]
True: [System.String] satisfies [System.Collections.Generic.IEnumerable`1[T]]
True: [System.String] satisfies [System.Collections.Generic.IEnumerable`1[System.Char]]
False: [System.String] satisfies [System.Collections.Generic.IEnumerable`1[System.Int32]]
True: [System.Int32] satisfies [System.Object]
True: [System.Int32] satisfies [System.IComparable]
True: [System.Collections.Generic.IReadOnlyDictionary`2[TKey,TValue]] satisfies [System.Collections.Generic.IReadOnlyCollection`1[T]]
False: [System.Boolean] satisfies [System.Numerics.INumber`1[TSelf]]
True: [System.Int32] satisfies [System.Numerics.INumber`1[TSelf]]
True: [System.Numerics.IBinaryInteger`1[TSelf]] satisfies [System.Numerics.IShiftOperators`2[TSelf,TResult]]
True: [System.Numerics.IBinaryInteger`1[System.Int32]] satisfies [System.Numerics.IShiftOperators`2[TSelf,TResult]]
True: [System.Numerics.IBinaryInteger`1[System.Int32]] satisfies [System.Numerics.IShiftOperators`2[System.Int32,System.Int32]]
INumber<>的例子来自。net 7预览5。
以前的回答
它可能是多余的,但我使用如下扩展方法。它们检查接口和子类。它还可以返回具有指定泛型定义的类型。
例如,对于问题中的例子,它可以测试泛型接口以及泛型类。返回的类型可以与GetGenericArguments一起使用,以确定泛型参数类型是“SomeType”。
/// <summary>
/// Checks whether this type has the specified definition in its ancestry.
/// </summary>
public static bool HasGenericDefinition(this Type type, Type definition)
{
return GetTypeWithGenericDefinition(type, definition) != null;
}
/// <summary>
/// Returns the actual type implementing the specified definition from the
/// ancestry of the type, if available. Else, null.
/// </summary>
public static Type GetTypeWithGenericDefinition(this Type type, Type definition)
{
if (type == null)
throw new ArgumentNullException("type");
if (definition == null)
throw new ArgumentNullException("definition");
if (!definition.IsGenericTypeDefinition)
throw new ArgumentException(
"The definition needs to be a GenericTypeDefinition", "definition");
if (definition.IsInterface)
foreach (var interfaceType in type.GetInterfaces())
if (interfaceType.IsGenericType
&& interfaceType.GetGenericTypeDefinition() == definition)
return interfaceType;
for (Type t = type; t != null; t = t.BaseType)
if (t.IsGenericType && t.GetGenericTypeDefinition() == definition)
return t;
return null;
}
JaredPar的代码可以工作,但只适用于一个继承级别。要获得无限级别的继承,请使用以下代码
public bool IsTypeDerivedFromGenericType(Type typeToCheck, Type genericType)
{
if (typeToCheck == typeof(object))
{
return false;
}
else if (typeToCheck == null)
{
return false;
}
else if (typeToCheck.IsGenericType && typeToCheck.GetGenericTypeDefinition() == genericType)
{
return true;
}
else
{
return IsTypeDerivedFromGenericType(typeToCheck.BaseType, genericType);
}
}
下面是我创建的一个小方法,用于检查对象是否派生于特定类型。对我来说太棒了!
internal static bool IsDerivativeOf(this Type t, Type typeToCompare)
{
if (t == null) throw new NullReferenceException();
if (t.BaseType == null) return false;
if (t.BaseType == typeToCompare) return true;
else return t.BaseType.IsDerivativeOf(typeToCompare);
}