/// <summary>
    /// Loads client's information when a client is selected from dropdownlist
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void clientIdDropDownList_SelectedIndexChanged(object sender, EventArgs e)
    {
        //When client change this information is not valid
        companyNameTextBox.Text   = "";
        contactPersonTextBox.Text = "";
        contactDateTextBox.Text   = "";
        addressTextBox.Text       = "";
        phoneNoTextBox.Text       = "";
        emailTextBox.Text         = "";
        errorLabel.Text           = "";
        successLabel.Text         = "";

        if (clientIdDropDownList.SelectedIndex.Equals(0))  // Item in index 0 is "-Select-" and not a valid item. So must not use
        {
            return;
        }

        try
        {
            ClientGateway ClientGatewayObject = new ClientGateway();
            Client        clientObject        = ClientGatewayObject.SelectClient(clientIdDropDownList.SelectedItem.Text);
            companyNameTextBox.Text   = clientObject.CompanyName;
            contactPersonTextBox.Text = clientObject.ContactPerson;
            contactDateTextBox.Text   = clientObject.ContactDate.ToString();
            addressTextBox.Text       = clientObject.Address;
            phoneNoTextBox.Text       = clientObject.PhoneNo;
            emailTextBox.Text         = clientObject.Email;
        }
        catch (SqlException sqlExceptionObj)
        {
            errorLabel.Text = sqlExceptionObj.Message;
        }
        catch (Exception exceptionObj)
        {
            errorLabel.Text = exceptionObj.Message;
        }
    }