在VC++中我几乎每一个Windows Service都是采用I/O完成端口。至于在C#中如何使用I/O完成端口，一直很少见人提及。 William Kennedy的三篇文章《IOCP Thread Pooling in C#》，对实现这种机制很有帮助，唯一美中不足的是，它只能把int数值压入完成端口，而无法像VC++中那样可以将接口指针/BSTR字符串等等转为OVERLAPPED*。我试了很多遍Marshal.PtrToStructure/StructureToPtr 和StringToBSTR,总是无法成功通过I/O完成端口传递string。
我还曾经用以下这2个函数将string转换为byte[]，然后将byte[]转换为NativeOverlapped。总是不行。
System.Threading.NativeOverlapped Ov = new NativeOverlapped();
byte[] btRaw = Str2Arr(strValue);
Ov = (System.Threading.NativeOverlapped)
RawDeserialize(btRaw, typeof(System.Threading.NativeOverlapped));
函数声明如下：
public static byte[] Str2Arr(String s)
{
return (new UnicodeEncoding()).GetBytes(s);
}
public static string Arr2Str(byte[] buffer)
{
return (new UnicodeEncoding()).GetString(buffer, 0, buffer.Length);
}
public static byte[] RawSerialize( object anything )
{
int rawsize = Marshal.SizeOf( anything );
IntPtr buffer = Marshal.AllocHGlobal( rawsize );
Marshal.StructureToPtr( anything, buffer, false );
byte[] rawdatas = new byte[ rawsize ];
Marshal.Copy( buffer, rawdatas, 0, rawsize );
Marshal.FreeHGlobal( buffer );
return rawdatas;
}
public static object RawDeserialize( byte[] rawdatas, Type anytype )
{
int rawsize = Marshal.SizeOf( anytype );
if( rawsize > rawdatas.Length )
return null;
IntPtr buffer = Marshal.AllocHGlobal( rawsize );
Marshal.Copy( rawdatas, 0, buffer, rawsize );
object retobj = Marshal.PtrToStructure( buffer, anytype );
Marshal.FreeHGlobal( buffer );
return retobj;
}