You use Reflection to obtain information about a method named MyMethod. You need to ascertain whether MyMethod is accessible to a derived class. What should you do?
使用反射得到方法MyMethod的信息。你需要确定MyMethod是否是可以应用于派生类。你要怎么做?
A、Call the IsAssembly property of the MethodInfo class.
B、Call the IsVirtual property of the MethodInfo class.
C、Call the IsStatic property of the MethodInfo class.
D、Call the IsFamily property of the MethodInfo class.
答案:D。
注意:A:是在程序集外的不可见。D:只要是派生类就可见
解:
IsAssembly:此方法或构造函数只对同一程序集中的其他类型可见,而对该程序集以外的派生类型则不可见。
IsFamily:此方法或构造函数仅在其类和派生类内可见。
IsVirtual:该值指示方法是否为 virtual
IsStatic:该值指示方法是否为 static
各定义对应的值:
IsPublic IsFamily IsFamilyAndAssembly
public True False False False False
internal False True False False False
protected False False True False False
protected internal False False False True False
测试代码:
新建两个控制台项目,如下图:
![](https://images.cnblogs.com/cnblogs_com/scottckt/MCPD/MCPDReflect.png)
在ReflectMCPD中编写下边代码。此类主要是通过反射得到方法的集息。
namespace ReflectMCPD
{
class Program
{
static void Main(string[] args)
{
System.Reflection.MemberInfo[] childMemberInfo = typeof(Father).GetMembers(
BindingFlags.Instance |
BindingFlags.NonPublic |
BindingFlags.Public);
foreach (MemberInfo infoItem in childMemberInfo)
{
switch (infoItem.MemberType)
{
case MemberTypes.All:
break;
case MemberTypes.Constructor:
break;
case MemberTypes.Custom:
break;
case MemberTypes.Event:
break;
case MemberTypes.Field:
break;
case MemberTypes.Method:
MethodInfo methodItemInfo = typeof(Father).GetMethod(infoItem.Name,
BindingFlags.Instance |
BindingFlags.NonPublic |
BindingFlags.Public);
if (methodItemInfo != null)
{
Console.WriteLine("方法名:{0},同一程序集可见:{1},类及派生类可见:{2}",
methodItemInfo.Name, methodItemInfo.IsAssembly, methodItemInfo.IsFamily);
}
break;
case MemberTypes.NestedType:
break;
case MemberTypes.Property:
break;
case MemberTypes.TypeInfo:
break;
default:
break;
}
}
Console.ReadKey();
}
}
/// <summary>
/// 父类
/// </summary>
public class Father
{
public string MyMethod()
{
return "测试";
}
internal void InternalMethod()
{
}
protected void ProtectedMetod()
{
}
protected internal void ProtectedInternalMetod()
{
}
}
}
在OtherReflect引用ReflectMCPD。编写如下代码。此类主要为了测试internal和protected在程序集以外的情况。
namespace OtherReflect
{
class Program
{
static void Main(string[] args)
{
}
}
public class SubChild : ReflectMCPD.Father
{
public void SubChildMethod()
{
ProtectedMetod();
ProtectedInternalMetod();
}
}
}