Question

我尝试编写一个泛型类型的转换方法，它既适用于复杂对象，也适用于对象数组。以下是我的代码：

public void Test()
{
     MyClass2[] t2 = m.MapItem<MyClass1[], MyClass2[]>(t1);
     return;
}

public K MapItem<T, K>(T source)
{
    if (typeof(T).IsArray && typeof(K).IsArray)
    {
        Type ek = typeof(K).GetElementType();
        IList sourceList = (IList)source;
        List<object> tmp = new List<object>();
        for (int i = 0; i < sourceList.Count; i++)
        {
            var k = Activator.CreateInstance(ek);
            tmp.Add(k);
        }
        var resultObj = tmp.ToArray();
        MapItem(source, resultObj);

        //Here i have resultObj is an object[] of the results,
        //which is to be casted result type K
        //BUT DOES NOT WORK!!!
        return (K)Convert.ChangeType(resultObj, typeof(K));

    }
    else
    {
        MethodInfo myMapperMethod = GetMyMapperMethodForThisType(typeof(T), typeof(K));
        return (K)myMapperMethod.Invoke(null, new object[] { source });
    }
}

public K MapItem<T, K>(T source, K dest)
{
    if (typeof(T).IsArray && typeof(K).IsArray)
    {
        IList sourceList = (IList)source;
        IList destList = (IList)dest;
        for (int i = 0; i < sourceList.Count; i++)
        {
            MapItem(sourceList[i], destList[i]);
        }
        return dest;
    }
    else
    {
        MethodInfo myMapperMethod = GetMyMapperMethodForThisType(typeof(T),typeof(K));
        return (K) myMapperMethod.Invoke(null, new object[] { source, dest });
    }
}

private MethodInfo GetMyMapperMethodForThisType(Type type1, Type type2)
{
    //some code to find appropriate function...
}

但是，return (K) Convert.ChangeType(y, typeof(K));无法从object[]投射到K。如何进行此投射以从K返回object[]？

注意：json序列化有效，但我不想使用反射或序列化。

  string jsonStr = JsonConvert.SerializeObject(resultObj);
  return JsonConvert.DeserializeObject<K>(jsonStr);

Answer 1

从根本上说，我认为你想避免使用List<object>。您应该只创建正确大小的数组：

IList dest = Array.CreateInstance(ek, sourceList.Count);
for (int i = 0; i < sourceList.Count; i++)
{
    dest[i] = Activator.CreateInstance(ek);
}
K result = (K) dest;
// Note that this is calling MapItem<T, K>, not MapItem<T, object[]>
MapItem(source, result);
return result;

输入对象[]到泛型类型K，它也是一个数组

1 个答案: