c# .NET 6.0 当您只有基础对象时，确定用于 Func<T> 的泛型类型

Question

假设我们有一个将常规对象作为参数的方法。我需要测试该对象是否为 Func，调用它并检索 return 值，但泛型类型可以是任何类型，我无法列出一长串可能性：

    public static object? Process(object o, out Type? type)
    {
        type = null;
        if (o is Action action) action();
        else if (o is int i) { type = typeof(long); return (long)i * (long)i; }
        else if (o is double d) { type = typeof(float); return (float)(d - (long)d); }
        else if (o is Func<int> funcint) { type = typeof(int); return funcint(); }
        else if (o is Func<string> funcstr) { type = typeof(string); return funcstr(); }
        else if (o is Func<object> funcobj) { type = typeof(object); return funcobj(); }
        // ...
        // ...
        return null;
    }

Answer 1

您可以通过反射获取参数类型，然后将 Func 转换为 `Delegate

Type t = o.GetType();
if (t.GetGenericTypeDefinition() == typeof(Func<>)
 && t.GetGenericArguments().Length == 1)
{
    type = t.GetGenericArguments()[0]; 
    return ((Delegate)o).DynamicInvoke(); 
}

c# .NET 6.0 当您只有基础对象时，确定用于 Func<T> 的泛型类型

c# .NET 6.0 Determine the generic type used for a Func<T> when all you have is the base object

c#

generics