C＃：具有继承类型的构造函数的函数
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我们知道，您可以像这样将构造函数指向
Func<T>
Func<MyObject> constructor = () => new MyObject();
var newObject = constructor();
Type inheritedObjectType = obj; // Parameter
Func<MyObject> constructor = () => new MyObject(); // as inheritedObjectType
var newInheritedObject = constructor; // Should now be of the inherited type
Activator
Object
没有找到相关结果
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2 个回复
傻寺俊擒
Func<TBase> CreateDelegate<TBase>(Type derived) { var ctor = derived.GetConstructor(Type.EmptyTypes); if (ctor == null) { throw new ArgumentException(\"D\'oh! No default ctor.\"); } var newExpression = Expression.Lambda<Func<TBase>>( Expression.New(ctor, new Expression[0]), new ParameterExpression[0]); return newExpression.Compile(); }缓存该委托时，将获得最佳性能。谷起
class MyObject{} class Derived : MyObject {} internal class Program { public static void Main() { // the type you want to construct Type type = typeof (Derived); MethodInfo getConstructor = MakeConstructorGetter(type); Func<MyObject> constructor = (Func<MyObject>)getConstructor.Invoke(null, null); var obj = constructor(); Console.WriteLine(obj.GetType()); } private static MethodInfo MakeConstructorGetter(Type type) { MethodInfo mi = typeof(Program).GetMethod(\"GetObjectConstructor\", BindingFlags.Static | BindingFlags.NonPublic); var getConstructor = mi.MakeGenericMethod(type); return getConstructor; } private static Func<T> GetObjectConstructor<T>() where T : MyObject, new() { return () => new T(); } }