/// <summary>
    /// Run the code example.
    /// </summary>
    /// <param name="user">The DFP user object running the code example.</param>
    public override void Run(DfpUser user) {
      // Get the CustomFieldService.
      CustomFieldService customFieldService = (CustomFieldService) user.GetService(
          DfpService.v201403.CustomFieldService);

      // Get the LineItemService.
      LineItemService lineItemService = (LineItemService) user.GetService(
          DfpService.v201403.LineItemService);

      // Set the IDs of the custom fields, custom field option, and line item.
      long customFieldId = long.Parse(_T("INSERT_STRING_CUSTOM_FIELD_ID_HERE"));
      long customFieldOptionId = long.Parse(_T("INSERT_CUSTOM_FIELD_OPTION_ID_HERE"));
      long lineItemId = long.Parse(_T("INSERT_LINE_ITEM_ID_HERE"));

      try {
        // Get the drop-down custom field id.
        long dropDownCustomFieldId =
            customFieldService.getCustomFieldOption(customFieldOptionId).customFieldId;

        StatementBuilder statementBuilder = new StatementBuilder()
            .Where("id = :id")
            .OrderBy("id ASC")
            .Limit(1)
            .AddValue("id", lineItemId);

        // Get the line item.
        LineItemPage lineItemPage = lineItemService.getLineItemsByStatement(
            statementBuilder.ToStatement());
        LineItem lineItem = lineItemPage.results[0];

        // Create custom field values.
        List<BaseCustomFieldValue> customFieldValues = new List<BaseCustomFieldValue>();
        TextValue textValue = new TextValue();
        textValue.value = "Custom field value";

        CustomFieldValue customFieldValue = new CustomFieldValue();
        customFieldValue.customFieldId = customFieldId;
        customFieldValue.value = textValue;
        customFieldValues.Add(customFieldValue);

        DropDownCustomFieldValue dropDownCustomFieldValue = new DropDownCustomFieldValue();
        dropDownCustomFieldValue.customFieldId = dropDownCustomFieldId;
        dropDownCustomFieldValue.customFieldOptionId = customFieldOptionId;
        customFieldValues.Add(dropDownCustomFieldValue);

        // Only add existing custom field values for different custom fields than
        // the ones you are setting.
        if (lineItem.customFieldValues != null) {
          foreach (BaseCustomFieldValue oldCustomFieldValue in lineItem.customFieldValues) {
            if (!(oldCustomFieldValue.customFieldId == customFieldId)
                && !(oldCustomFieldValue.customFieldId == dropDownCustomFieldId)) {
              customFieldValues.Add(oldCustomFieldValue);
            }
          }
        }

        lineItem.customFieldValues = customFieldValues.ToArray();

        // Update the line item on the server.
        LineItem[] lineItems = lineItemService.updateLineItems(new LineItem[] {lineItem});

        if (lineItems != null) {
          foreach (LineItem updatedLineItem in lineItems) {
            List<String> customFieldValueStrings = new List<String>();
            foreach (BaseCustomFieldValue baseCustomFieldValue in lineItem.customFieldValues) {
              if (baseCustomFieldValue is CustomFieldValue
                  && ((CustomFieldValue) baseCustomFieldValue).value is TextValue) {
                customFieldValueStrings.Add("{ID: '" + baseCustomFieldValue.customFieldId
                    + "', value: '"
                    + ((TextValue) ((CustomFieldValue) baseCustomFieldValue).value).value
                    + "'}");
              } else if (baseCustomFieldValue is DropDownCustomFieldValue) {
                customFieldValueStrings.Add("{ID: '" + baseCustomFieldValue.customFieldId
                    + "', custom field option ID: '"
                    + ((DropDownCustomFieldValue) baseCustomFieldValue).customFieldOptionId
                    + "'}");
              }
            }
            Console.WriteLine("A line item with ID \"{0}\" set with custom field values \"{1}\".",
                updatedLineItem.id, string.Join(", ", customFieldValueStrings.ToArray()));
          }
        } else {
          Console.WriteLine("No line items were updated.");
        }
      } catch (Exception ex) {
        Console.WriteLine("Failed to update line items. Exception says \"{0}\"", ex.Message);
      }
    }
 /// <summary>
 /// Adds a new string value to the list of query parameters.
 /// </summary>
 /// <param name="key">The parameter name.</param>
 /// <param name="value">The parameter value.</param>
 /// <returns>The statement builder, for chaining method calls.</returns>
 public StatementBuilder AddValue(string key, string value) {
   TextValue queryValue = new TextValue();
   queryValue.value = value;
   return AddValue(key, queryValue);
 }