protected void updateButton_Click(object sender, EventArgs e)
    {
        string message = null;

        if (!CheckInputValues())
        {
            return;
        }

        Client clientObject = new Client();

        clientObject.Id            = clientIdDropDownList.SelectedItem.Text;
        clientObject.CompanyName   = companyNameTextBox.Text;
        clientObject.ContactPerson = contactPersonTextBox.Text;
        clientObject.ContactDate   = Convert.ToDateTime(contactDateTextBox.Text);
        clientObject.Address       = addressTextBox.Text;
        clientObject.PhoneNo       = phoneNoTextBox.Text;
        clientObject.Email         = emailTextBox.Text;

        try
        {
            ClientGateway ClientGatewayObject = new ClientGateway();
            message = ClientGatewayObject.UpdateClient(clientObject).ToString();
            if (message == "True")
            {
                message = "Data has been updated successfully";
            }
        }
        catch (SqlException sqlExceptionObj)
        {
            errorLabel.Text = sqlExceptionObj.Message;
        }
        catch (Exception exceptionObj)
        {
            errorLabel.Text = exceptionObj.Message;
        }
        successLabel.Text = message;
        errorLabel.Text   = "";
    }