C# 调 DLL 获取函数值的问题，请大神们帮个忙，谢了，两天了没有弄出来，在线等

VC的接口
Bool GetKeyPadStatus( byte * addr, char * pstatus, char * pnumber,byte* ptocounter);

C# 调用
[DllImport("KeyPad.dll", CallingConvention = CallingConvention.StdCall)]
public static extern bool GetKeyPadstatus(ref byte addr, ref string pstatus, ref string pnumber, ref byte ptocounter); //获取终端状态函数

调用函数

byte address1 = 1;
//byte address2 = 2;
string pstatus = "0"; //////////这个值
string pnumber = "0000";
byte mtocounter = 0;//

bool temp = calldll.GetKeyPadstatus(ref address1, ref pstatus, ref pnumber, ref mtocounter);
if (temp)
{
switch (pstatus[0])
{
case '0':
label7.Text = "怎么是0 零 没有获得呼叫器的状态值";
break;
case 'L':
label7.Text = "空闲状态，按了清除键了";
break;
case 'E':
label7.Text = "暂停状态，按了暂停键";
break;
case 'W':
label7.Text = "等待" + pnumber;
break;
case 'P':
label7.Text = "呼叫" + pnumber; //重复呼叫
CallAndPrint();
break;
case 'M':
label7.Text = "转移" + pnumber + "到" + mtocounter.ToString() + "窗口";
break;
case 'S':
label7.Text = "正在受理" + pnumber; break;
case 'U':
label7.Text = "呼叫器要求派号";
byte waitnum = 100; //等待人数
calldll.setKeyPadnumber(ref address1, ref pnumber, waitnum);
Thread.Sleep(120);
CallAndPrint();
break;
}
}
最后获取的pstatus 值 是 0 也就是我开始刚给他的赋值

没有分了 只有25分了，昨天因为没分没能发帖。急死人！！