在之前，遇到下拉框的时候我们可以用两次点击来选择我们需要的选项，不过对于下拉框，我们的webdriver中有封装的Select包单独对于下拉框有一套处理的方法，我们可以来学习一下，然后在测试的时候根据不同的情况来选择需要哪儿种方法。
1.select包方法的使用示例以及定位方式
select下拉框的定位
2.select包内的方法详解
1.获取option元素
options：获取包含select下拉框内所有option项element的列表
all_selected_options: 获取当前选中项element的列表
first_selected_option:获取所有下拉选项中的第一个选项的element（或者获取当前选中的这一项）
2.选择option
select_by_value(values)：选择option标签中value属性为：values的选项
select_by_index(index_number)：选择索引为index_number的选项（索引从0开始）
select_by_visible_text(text)：选择option选项内容为：text的选项
3.复选select的情况（select标签中，multiple="multiple"时，即可多选的select选择框）
deselect_all: 取消所有已选择的选项
deselect_by_value(values):取消选择option标签中value属性为：values的选项
deselect_by_index(index_number)：取消选择索引为index_number的选项（索引从0开始）
deselect_by_visible_text(text)：取消选择option选项内容为：text的选项
3.实例验证（一）百度贴吧高级搜索下拉框
本条实例主要是获取选项元素和通过方法来选择某项option，代码如下
from selenium import webdriver
from selenium.webdriver.support.ui import Select
from time import sleep
# 打开Chrome浏览器
driver = webdriver.Chrome()
# 进入百度高级搜索页
driver.get("http://tieba.baidu.com/f/search/adv")
# 获取select下拉框的元素
ele_select = driver.find_element_by_css_selector("select[name='sm']")
# 获取下拉框中所有选项元素（element）
options = Select(ele_select).options
print("所有选项元素的列表：%s" % options)
for i in options:
print("元素对应的选项：%s"% i.text)
# 获取下拉框当前显示(选中)的元素(element)
options_selected = Select(ele_select).all_selected_options
print("-----------------------分隔符---------------------------")
print(options_selected)
for j in options_selected:
print("当前选中的选项(默认项)：%s" % j.text)
# 选择value值为2的选项
Select(ele_select).select_by_value("2")
sleep(1)
# 输出默认项(当前选中项）
now = Select(ele_select).first_selected_option
print(now.text)
4.实例验证（二）w3c多选multiple选择框
由于w3c并没有多选multiple这一项，所以我们把我们自己写的表单信息给写入到页面上，然后再进行多选select框的验证
from selenium import webdriver
from selenium.webdriver.support.ui import Select
from time import sleep
# 打开浏览器，进入演示页面
driver = webdriver.Chrome()
driver.get("http://www.w3school.com.cn/tiy/t.asp?f=html_dropdownbox")
# 定位输入框文本域
ele_textarea = driver.find_element_by_css_selector("#TestCode")
# 清空文本域
ele_textarea.clear()
# 输入多选下拉框的演示源码 (multiple="multiple")
texts = "<html> "
"<body><form><select multiple="multiple" name="cars"><option value="volvo">Volvo</option>"
"<option value="saab">Saab</option><option value="fiat">Fiat</option>"
"<option value="audi">Audi</option></select></form></body></html>"
ele_textarea.send_keys(texts)
# 点击提交代码
submit_button = driver.find_element_by_css_selector("#butt > input[type='button']")
submit_button.click()
sleep(2)
# 定位frame和select元素
driver.switch_to.frame("i")
ele_select = driver.find_element_by_css_selector("body > form > select")
# 选择全部的选项（多选）
Select(ele_select).select_by_index(0)
Select(ele_select).select_by_index(1)
Select(ele_select).select_by_index(2)
Select(ele_select).select_by_index(3)
# 取消选择第一项选项（页面上可以观察到变化）
Select(ele_select).deselect_by_index(0)
# 输出当前选择的第一项
now = Select(ele_select).first_selected_option
print(now.text)
5.源码展示
class Select(object): def __init__(self, webelement): """ Constructor. A check is made that the given element is, indeed, a SELECT tag. If it is not, then an UnexpectedTagNameException is thrown. :Args: - webelement - element SELECT element to wrap Example: from selenium.webdriver.support.ui import Select Select(driver.find_element_by_tag_name("select")).select_by_index(2) """ if webelement.tag_name.lower() != "select": raise UnexpectedTagNameException( "Select only works on <select> elements, not on <%s>" % webelement.tag_name) self._el = webelement multi = self._el.get_attribute("multiple") self.is_multiple = multi and multi != "false" @property def options(self): """Returns a list of all options belonging to this select tag""" return self._el.find_elements(By.TAG_NAME, 'option') @property def all_selected_options(self): """Returns a list of all selected options belonging to this select tag""" ret = [] for opt in self.options: if opt.is_selected(): ret.append(opt) return ret @property def first_selected_option(self): """The first selected option in this select tag (or the currently selected option in a normal select)""" for opt in self.options: if opt.is_selected(): return opt raise NoSuchElementException("No options are selected") def select_by_value(self, value): """Select all options that have a value matching the argument. That is, when given "foo" this would select an option like: <option value="foo">Bar</option> :Args: - value - The value to match against throws NoSuchElementException If there is no option with specisied value in SELECT """ css = "option[value =%s]" % self._escapeString(value) opts = self._el.find_elements(By.CSS_SELECTOR, css) matched = False for opt in opts: self._setSelected(opt) if not self.is_multiple: return matched = True if not matched: raise NoSuchElementException("Cannot locate option with value: %s" % value) def select_by_index(self, index): """Select the option at the given index. This is done by examing the "index" attribute of an element, and not merely by counting. :Args: - index - The option at this index will be selected throws NoSuchElementException If there is no option with specisied index in SELECT """ match = str(index) for opt in self.options: if opt.get_attribute("index") == match: self._setSelected(opt) return raise NoSuchElementException("Could not locate element with index %d" % index) def select_by_visible_text(self, text): """Select all options that display text matching the argument. That is, when given "Bar" this would select an option like: <option value="foo">Bar</option> :Args: - text - The visible text to match against throws NoSuchElementException If there is no option with specisied text in SELECT """ xpath = ".//option[normalize-space(.) = %s]" % self._escapeString(text) opts = self._el.find_elements(By.XPATH, xpath) matched = False for opt in opts: self._setSelected(opt) if not self.is_multiple: return matched = True if len(opts) == 0 and " " in text: subStringWithoutSpace = self._get_longest_token(text) if subStringWithoutSpace == "": candidates = self.options else: xpath = ".//option[contains(.,%s)]" % self._escapeString(subStringWithoutSpace) candidates = self._el.find_elements(By.XPATH, xpath) for candidate in candidates: if text == candidate.text: self._setSelected(candidate) if not self.is_multiple: return matched = True if not matched: raise NoSuchElementException("Could not locate element with visible text: %s" % text) def deselect_all(self): """Clear all selected entries. This is only valid when the SELECT supports multiple selections. throws NotImplementedError If the SELECT does not support multiple selections """ if not self.is_multiple: raise NotImplementedError("You may only deselect all options of a multi-select") for opt in self.options: self._unsetSelected(opt) def deselect_by_value(self, value): """Deselect all options that have a value matching the argument. That is, when given "foo" this would deselect an option like: <option value="foo">Bar</option> :Args: - value - The value to match against throws NoSuchElementException If there is no option with specisied value in SELECT """ if not self.is_multiple: raise NotImplementedError("You may only deselect options of a multi-select") matched = False css = "option[value = %s]" % self._escapeString(value) opts = self._el.find_elements(By.CSS_SELECTOR, css) for opt in opts: self._unsetSelected(opt) matched = True if not matched: raise NoSuchElementException("Could not locate element with value: %s" % value) def deselect_by_index(self, index): """Deselect the option at the given index. This is done by examing the "index" attribute of an element, and not merely by counting. :Args: - index - The option at this index will be deselected throws NoSuchElementException If there is no option with specisied index in SELECT """ if not self.is_multiple: raise NotImplementedError("You may only deselect options of a multi-select") for opt in self.options: if opt.get_attribute("index") == str(index): self._unsetSelected(opt) return raise NoSuchElementException("Could not locate element with index %d" % index) def deselect_by_visible_text(self, text): """Deselect all options that display text matching the argument. That is, when given "Bar" this would deselect an option like: <option value="foo">Bar</option> :Args: - text - The visible text to match against """ if not self.is_multiple: raise NotImplementedError("You may only deselect options of a multi-select") matched = False xpath = ".//option[normalize-space(.) = %s]" % self._escapeString(text) opts = self._el.find_elements(By.XPATH, xpath) for opt in opts: self._unsetSelected(opt) matched = True if not matched: raise NoSuchElementException("Could not locate element with visible text: %s" % text) def _setSelected(self, option): if not option.is_selected(): option.click() def _unsetSelected(self, option): if option.is_selected(): option.click() def _escapeString(self, value): if '"' in value and "'" in value: substrings = value.split(""") result = ["concat("] for substring in substrings: result.append(""%s"" % substring) result.append(", '"', ") result = result[0:-1] if value.endswith('"'): result.append(", '"'") return "".join(result) + ")" if '"' in value: return "'%s'" % value return ""%s"" % value def _get_longest_token(self, value): items = value.split(" ") longest = "" for item in items: if len(item) > len(longest): longest = item return longest