c# - システム無効操作例外エラー

Question

昨日、私は 2 つのフォームを作成しました。最初のフォームはクライアント アウト ネットワークのリッスン要求です。2 番目のフォームは MessageBox のようなフォーム アラート (MessageBox カスタム) ですが、クライアントが最初のフォームに接続要求を送信すると、2 番目のフォームが表示されます。しかし、任意のボタンをクリックしてフォームを閉じた後、以下のメッセージを受け取りました。

タイトル: System.InvalidOperationException 詳細: 元に戻す操作で、対応するセット操作で適用されたものとは異なるコンテキストが検出されました。考えられる原因は、コンテキストがスレッドで設定され、元に戻されていない (元に戻されていない) ことです。

最初の投稿者:

//Nhận các yêu cầu và kiểm tra và gửi phản hồi
    private void OnReceive(IAsyncResult ar)
    {
        try
        {
            EndPoint receivedFromEP = new IPEndPoint(IPAddress.Any, 0);

            //Get the IP from where we got a message.
            clientSocket.EndReceiveFrom(ar, ref receivedFromEP);

            //Convert the bytes received into an object of type Data.
            Data(byteData);

            //Act according to the received message.
            switch (cmdCommand)
            {
                //We have an incoming call.
                case Command.Invite:
                    {
                        if (bIsCallActive == false)
                        {
                            //We have no active call.                                
                            //Ask the user to accept the call or not.                                

                            DialogResult result = ThongBaoCoDienThoai.HienHopThoai(strName);                                

                            if (result == DialogResult.Yes)
                            {
                                //SendMessage(Command.OK, receivedFromEP);                                    
                                //Bắt đầu kết nôi
                                //**********************************GOI PHUONg THUC GUI NHAN DONG BO AM THANH****************                                    
                            }
                            else
                            {
                                //The call is declined. Send a busy response.
                               //SendMessage(Command.Busy, receivedFromEP);
                            }                        

                        }
                        else
                        {
                            //We already have an existing call. Send a busy response.
                            SendMessage(Command.Busy, receivedFromEP);
                        }
                        break;
                    }

                //OK is received in response to an Invite.
                case Command.OK:
                    {
                        //Start a call.                            
                        break;
                    }

                //Remote party is busy.
                case Command.Busy:
                    {
                        MessageBox.Show("User busy.", "VoiceChat", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                        break;
                    }

                case Command.Bye:
                    {
                        //Check if the Bye command has indeed come from the user/IP with which we have
                        //a call established. This is used to prevent other users from sending a Bye, which
                        //would otherwise end the call.
                        if (receivedFromEP.Equals(otherPartyEP) == true)
                        {
                            //End the call.

                        }
                        break;
                    }
            }

            byteData = new byte[1024];
            //Get ready to receive more commands.
            clientSocket.BeginReceiveFrom(byteData, 0, byteData.Length, SocketFlags.None, ref receivedFromEP, new AsyncCallback(OnReceive), null);
        }
        catch (Exception ex)
        {
            MessageBox.Show("OnReceive: " + ex.Message, "Error");
        }
    }

2 番目のフォーム:

static ThongBaoCoDienThoai tbcdt;
    static DialogResult kq = DialogResult.No;
    private Timer thoiGian;         
    int henGioTat; //Hẹn thời gian tắt form
    SoundPlayer player; //Khởi tạo thiết bị phát (Loa)

    public ThongBaoCoDienThoai()
    {
        InitializeComponent();
        try
        {
            henGioTat = 30;
            thoiGian = new Timer();
            thoiGian.Interval = 1000;
            thoiGian.Enabled = true;
            thoiGian.Start();
            thoiGian.Tick += new EventHandler(this.thoiGian_Tick);

            //Hiển thị hộp thông báo ở góc màng hình dưới bên phải
            Rectangle r = Screen.PrimaryScreen.WorkingArea;
            this.StartPosition = FormStartPosition.Manual;
            this.Location = new Point(Screen.PrimaryScreen.WorkingArea.Width - this.Width, Screen.PrimaryScreen.WorkingArea.Height - this.Height);

            //Phát âm thành khi form được mở  
            player = new SoundPlayer(Properties.Resources.ringing);
            player.Load();
            player.PlayLooping();

        }
        catch (Exception ex)
        {
            MessageBox.Show("ThongBaoCoDienThoai_Load :" + ex.Message, "Error");
        }
    }

    public static DialogResult HienHopThoai(string tenNguoiGoi)
    {            
        try
        {
            tbcdt = new ThongBaoCoDienThoai();
            tbcdt.lbThongBao.Text = tenNguoiGoi + " đang gọi........";
            tbcdt.ShowDialog();                
        }
        catch (Exception ex)
        {
            MessageBox.Show("HienHopThoai: "+ex.Message,"Error");
        }
        return kq;
    }        

    private void btHuy_Click(object sender, EventArgs e)
    {
        tbcdt.thoiGian.Stop();
        tbcdt.thoiGian.Dispose();
        kq = DialogResult.No;
        tbcdt.Dispose();            
    }

    private void btNhan_Click(object sender, EventArgs e)
    {
        ThongBaoCoDienThoai tbcdt = new ThongBaoCoDienThoai();
        alertControl1.Show(tbcdt);
        tbcdt.thoiGian.Stop();
        tbcdt.thoiGian.Dispose();
        kq = DialogResult.Yes;
        tbcdt.Dispose();
    }        

    private void thoiGian_Tick(object sender, EventArgs e)
    {
        henGioTat--;

        if (henGioTat == 0)
        {
            tbcdt.thoiGian.Stop();
            tbcdt.thoiGian.Dispose();
            tbcdt.Dispose();
        }
    }

    private void ThongBaoCoDienThoai_FormClosing(object sender, FormClosingEventArgs e)
    {
        player.Stop();            
    }