我想用反射调用类的每个方法,但是我不能用指针调用方法作为参考。通常我只能为我找到的每个指针传递null,一切都会好的。问题是当函数试图访问我传递的指针时。指针将是对内存地址0的引用,这显然是我程序的即时崩溃。 所以我需要将指针传递给有效的内存地址,但我不知道如何在运行时创建指针
我的代码的压缩版本:
class Program
{
static void Main(string[] args)
{
var obj = new TestClass();
var pointerMethod = obj.GetType().GetMethod("Test");
var referenceMethod = obj.GetType().GetMethod("Test2");
var pointerParameter = pointerMethod.GetParameters()[0];
var referenceParameter = referenceMethod.GetParameters()[0];
//Get the instance of the class that is referred by the pointer/reference
var pointerInstance = Activator.CreateInstance(pointerParameter.ParameterType.GetElementType());
var referenceInstance = Activator.CreateInstance(referenceParameter.ParameterType.GetElementType());
//Call the method and "cast" the char instance into an pointer
pointerMethod.Invoke(obj, new[] {pointerInstance.GetType().MakePointerType()});
referenceMethod.Invoke(obj, new[] { referenceInstance.GetType().MakeByRefType() });
}
}
和TestClass:
public class TestClass
{
unsafe public void Test(char* pointer)
{
}
public void Test2(ref int reference)
{
}
}
我总是得到例外" System.RuntimeType"无法转换为' System.Char *' 奇怪的是,pointerInstance.GetType()。MakePointerType()返回一个char *,正是我必须传递给函数...
答案 0 :(得分:8)
首先,让我们将其分为指针vs ref
- 它们的处理方式略有不同。
目前还不清楚你期望接收方法的指针值 - 特别是当你传递给Invoke
的值是一个类型,而不是类型的实例 - 但你应该使用Pointer.Box
:
using System.Reflection;
class TestPointer
{
unsafe static void Main()
{
char c = 'x';
char* p = &c;
object boxedPointer = Pointer.Box(p, typeof(char*));
var method = typeof(TestPointer).GetMethod("Foo");
method.Invoke(null, new[] { boxedPointer });
Console.WriteLine("After call, c = {0}", c);
}
public static unsafe void Foo(char *pointer)
{
Console.WriteLine("Received: {0}", *pointer);
*pointer = 'y';
}
}
输出:
Received: x
After call, c = y
对于ref
参数,它稍微简单一点 - 您只允许正常装箱,并且参数数组已更改:
using System.Reflection;
class TestRef
{
unsafe static void Main()
{
var method = typeof(TestRef).GetMethod("Foo");
var args = new object[] { 10 };
method.Invoke(null, args);
Console.WriteLine("After call, args[0] = {0}", args[0]);
}
public static unsafe void Foo(ref int x)
{
Console.WriteLine("Received: {0}", x);
x = 20;
}
}