这里是整理编辑一下我的原博文
http://sheenspace.wordpress.com/2010/09/19/question-about-net-gc/
从.NET 2.0开始,加入了SafeHandle类用来避免unmaged资源被提前非预期的释放。关于SafeHandle,参看MSDN:
http://msdn.microsoft.com/en-us/library/system.runtime.interopservices.safehandle.aspx
这里用一个例子重现IntPtr被提前释放的情况:
class C1
{
// Some unmanaged resource handle
IntPtr _handle = IntPtr.Zero;
static void OperateOnHandle(IntPtr h)
{
GC.Collect();
GC.WaitForPendingFinalizers();
Console.WriteLine("After GC.Collect() call");
// Use the IntPtr here. Oops, invalid operation
}
public void m()
{
OperateOnHandle(_handle);
}
~C1()
{
// Release and destroy IntPtr here
Console.WriteLine("In destructor");
}
}
class Program
{
static void Main(string[] args)
{
C1 aC = new C1();
aC.m();
}
}
该例子由MSDN专家cbrumme文章中代码改造而来
http://blogs.msdn.com/b/cbrumme/archive/2003/04/19/51365.aspx?wa=wsignin1.0