public VideoChatInfo()
 {
     state      = VChatState.kVChatUnknow;
     channel_id = 0;
     uid        = "";
     chat_mode  = NIMVideoChatMode.kNIMVideoChatModeAudio;
 }
        private void ChangeVchatState(VChatState state)
        {
            switch (state)
            {
            case VChatState.kVChatInvite:
            {
                panel_invite.Visible      = true;
                panel_notify.Visible      = false;
                panel_chating.Visible     = false;
                panel_end.Visible         = false;
                lb_invite_info.Text       = "正在呼叫" + vchat_info.uid + " ,请稍等";
                btn_invite_cancel.Enabled = true;
                CallFriend(vchat_info.uid);
            }
            break;

            case VChatState.kVChatInviteRefuse:
            {
                panel_invite.Visible      = true;
                panel_notify.Visible      = false;
                panel_chating.Visible     = false;
                panel_end.Visible         = false;
                lb_invite_info.Text       = "对方已拒绝";
                btn_invite_cancel.Enabled = false;
                TimerCloseForm();
            }
            break;

            case VChatState.kVChatNotify:
            {
                panel_invite.Visible  = false;
                panel_notify.Visible  = true;
                panel_chating.Visible = false;
                panel_end.Visible     = false;
                lb_notify_info.Text   = vchat_info.uid +
                                        (vchat_info.chat_mode == NIMVideoChatMode.kNIMVideoChatModeAudio ? "向你发来音频通话" : "向你发来视频通话");
            }
            break;

            case VChatState.kVChating:
            {
                panel_invite.Visible  = false;
                panel_notify.Visible  = false;
                panel_chating.Visible = true;
                panel_end.Visible     = false;
            }
            break;

            case VChatState.VChatEnd:
            {
                panel_invite.Visible  = false;
                panel_notify.Visible  = false;
                panel_chating.Visible = false;
                panel_end.Visible     = true;
                lb_end_info.Text      = "对方已挂断";
                TimerCloseForm();
            }
            break;
            }
        }