win7 64位 为什么触发不了下面函数？

private void axWindowsMediaPlayer1_PlayStateChange(object sender, AxWMPLib._WMPOCXEvents_PlayStateChangeEvent e)
{

        switch (e.newState)
        {
            case 0:
                MessageBox.Show("Undefined");
                break;
            case 1:
                MessageBox.Show("Stopped");
                break;
            case 2:
                MessageBox.Show("Paused");
                break;
            case 3:
                MessageBox.Show("Playing");
                break;
            case 4:
                MessageBox.Show("ScanForward");
                break;
            case 5:
                MessageBox.Show("ScanReverse");
                break;
            case 6:
                MessageBox.Show("Buffering");
                break;
            case 7:
                MessageBox.Show("Waiting");
                break;
            case 8:
                MessageBox.Show("MediaEnded");
                break;
            case 9:
                MessageBox.Show("Transitioning");
                break;
            case 10:
                MessageBox.Show("Ready");
                break;
            case 11:
                MessageBox.Show("Reconnecting");
                break;
            case 12:
                MessageBox.Show("Last");
                break;
            default:
                MessageBox.Show("Undefined");
                break;
        }
    }

在构造函数里面加上
axWindowsMediaPlayer1.PlayStateChange += new AxWMPLib._WMPOCXEvents_PlayStateChangeEventHandler(xWindowsMediaPlayer1_PlayStateChange);

肯定加了啊，要不然还不得报错

 this.axWindowsMediaPlayer1.PlayStateChange += new AxWMPLib._WMPOCXEvents_PlayStateChangeEventHandler(this.axWindowsMediaPlayer1_PlayStateChange)

加上MessageBox.Show(e.newState.ToString());看看执行么

打了断点，根本进不去函数