DBNull Exceptin: The value for column 'WinAut' in table 'Operator' is DBNull.

private void SetUserDetails()
        {
            Int32 intUserId = 0;
            if (gridViewUsers.Rows.Count > 0)
            {
                if (gridViewUsers.SelectedRows.Count == 0)
                    intUserId = Convert.ToInt32(gridViewUsers.Rows[0].Cells["Operator_ID"].Value);
                else
                    intUserId = Convert.ToInt32(gridViewUsers.SelectedRows[0].Cells["Operator_ID"].Value);
 
                DsOperatorAccess.OperatorRow drUser = dsOperatorAccess1.Operator.FindByOperator_ID(intUserId);
 
                TmpOperator_Id = intUserId;
 
                txtUserName.Text = drUser.UserName;
                txtFirstName.Text = drUser.FirstName;
                txtLastName.Text = drUser.LastName;
                txtEmail.Text = drUser.Email;
                txtPassword.Text = "";
                chkAdmin.Checked = Convert.ToBoolean(drUser.Admin);
                chkInUse.Checked = Convert.ToBoolean(drUser.InUse);
                chkWinAuthOperator.Checked = drUser.WinAut;    // Getting error HERE
                lstLanguage.SelectedIndex = lstLanguage.FindStringExact(drUser.Language);
                BindOperatorAccess(drUser);
            }
        }