I using thread but GUI freeze

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WinForms

C#5.0

I have a method:

private void CheckMsDevices() {
    string DevicesID;
    string IPAddress;
    int Port;
    int CommKey;

    Dt = new DataTable();
    StrSQL = "select DevicesID, IPAddress, Port, CommKey from MsDevices";
    if (cldb.sqlSelectReturnDt(StrSQL, Dt) == 1) {
        for (int i = 0; i < Dt.Rows.Count; i++) {
            DevicesID = Convert.ToString(Dt.Rows[i]["DevicesID"]);
            IPAddress = Convert.ToString(Dt.Rows[i]["IPAddress"]);
            Port = Convert.ToInt32(Dt.Rows[i]["Port"]);
            CommKey = Convert.ToInt32(Dt.Rows[i]["CommKey"]);

            Cursor = Cursors.WaitCursor;
            axCZKEM1.SetCommPassword(CommKey);
            bIsConnected = axCZKEM1.Connect_Net(IPAddress, Port);
            if (bIsConnected == true) {
                StrSQL = "update MsDevices set Status=1, EditBy='" + MasterForm.UserName + "', EditDate=GetDate() where DevicesID='" + DevicesID + "'";
                cldb.SqlExecuteQuery(StrSQL);

                axCZKEM1.RegEvent(1, 65535);
            } else {
                StrSQL = "update MsDevices set Status=0, EditBy='" + MasterForm.UserName + "', EditDate=GetDate() where DevicesID='" + DevicesID + "'";
                cldb.SqlExecuteQuery(StrSQL);
            }
        }

        BindData();
    }
}

which the method is used to check whether connected or not with finger print.


and my class construction

public FrmMsDevices() {
            InitializeComponent();

            Control.CheckForIllegalCrossThreadCalls = false;

            Thread.Sleep(120000);
            Thread t = new Thread(CheckMsDevices);
            t.IsBackground = true;
            t.Start();
        }

But at run time GUI freeze.
What should I do and how that does not happen freeze?

Thank you.