/// <summary>
/// This method evaluates if one IWebElement contains a child selected by the predicate. It can be used to select
/// one container element based on its child elements.
/// </summary>
/// <param name="element">The container element to be evaludated.</param>
/// <param name="childEnum">Enum Identifier of the child element, which carries the CSS selector.</param>
/// <param name="predicate">Function to see if the child element meets predefined criteria.</param>
/// <returns>"true": The container IWebElement contains the expected child IWebElement, otherwise "false".</returns>
public static bool HasChildOf(this IWebElement element, Enum childEnum, Func <IWebElement, bool> predicate)
{
string childLocatorCss = childEnum.Css();
IWebElement child = null;
try
{
//child = GenericWait<IWebElement>.Until(() =>
// element.FindElementByCss(childLocatorCss), null, 1000);
ReadOnlyCollection <IWebElement> candidates = null;
candidates = GenericWait <ReadOnlyCollection <IWebElement> > .Until(
() => candidates = element.FindElementsByCss(childLocatorCss),
x => x.Count != 0,
200
);
var qualified = candidates.Where(predicate).ToList();
bool result = qualified.Count != 0;
return(result);
}
catch (Exception)
{
return(false);
}
}
/// <summary>
/// Assuming Elements can be found with CSS selector within time specified by waitInMills, keep executing the
/// FindElementsByCssSelector() of either Driver or a specific IWebElement until timeout.
/// </summary>
/// <param name="findFunc">The FindElementsByCssSelector() of either Driver or a specific IWebElement.</param>
/// <param name="css">CSS Selector string.</param>
/// <param name="waitInMills">Maximum time to wait when the findFunc returns 0-length collection.</param>
/// <returns>The non-empty collection immediately or empty collection after time is out.</returns>
public ReadOnlyCollection <IWebElement> WaitToFindElements(Func <string, ReadOnlyCollection <IWebElement> > findFunc,
string css,
int waitInMills)
{
return(GenericWait <ReadOnlyCollection <IWebElement> > .Until(
() => findFunc(css), collction => collction.Count != 0, waitInMills
));
}
//Stores the last calling of FindElement() to avoid InvalidElementStateException or StaleElementReferenceException.
//private long lastTick = Int64.MinValue;
#endregion
/// <summary>
/// Retrieve the IWebElement based on the CSS associated with the Enum Identifier, and optional
/// the filters when Enum Identifier selects a collection.
/// </summary>
/// <param name="filters">
/// ByIndex to select one IWebElement from a collection of them, would be used by this Locator and its parents.
/// For Locator of a single IWebElement whose IsCollection=="false", filters is always neglected.
/// For Locator of multiple IWebElements whose IsCollection=="true",
/// filters is used to choose from a Collection returned by FindElementsByCssSelector().
/// Noticeably, the filters is sticky. That is, if one Locator uses a filters, then it and its parent would store
/// it for following calling of FindElement(null).
/// The defintion of filters is similar to Queryable.Where<TSource> Method (IQueryable<TSource>, Expression<Func<TSource, Int32, Boolean>>)
/// <seealso cref="http://msdn.microsoft.com/en-us/library/vstudio/bb548547(v=vs.100).aspx"/>
/// </param>
/// <returns>
/// The IWebElement chosen by the CSS selector and the filters, and casted to IWebElement.
/// </returns>
public virtual IWebElement FindElement(Func <IWebElement, bool> filters = null, int waitInMills = DefaultWaitToFindElement)
{
//TODO: if it is necessary to validate the lastSelectedELement or regard it as valid within a limited time?
//*/ Perform some simple operation to validate that the lastFoundElement is still valid
if (lastFoundElement != null && (filters == null || filters == lastFilters) &&
lastFoundElement.IsValid())
{
return(lastFoundElement);
}
/*/
* //Otherwise, using the Environment.Ticks to make sure each Element is valid for a limited time (1 second)
* if (lastFoundElement != null && (filters == null || filters == lastFilters)
* //&& (Environment.TickCount-lastTick<ValidElementStatePeriodInTicks)
* )
* return lastFoundElement;
* //*/
IWebElement parentElement = null;
if (Parent != null && !Parent.Identifier.Equals(HtmlByCustom.Root))
{
parentElement = Parent.FindElement(filters, waitInMills);
if (parentElement == null || !parentElement.IsValid())
{
return(null);
}
}
string css = Identifier.Css();
//When CSS matches multiple IWebElements, further selection shall be applied by filters
//Or, When selection is based on ByText mechanism, then EnumMember.Value is used
if (Identifier.IsCollection() || Identifier.Mechanism().Equals(Mechanisms.ByText))
{
Func <string, ReadOnlyCollection <IWebElement> > findFunc = (parentElement == null) ?
(Func <string, ReadOnlyCollection <IWebElement> >)DriverManager.FindElementsByCssSelector : parentElement.FindElementsByCss;
//Select the candidate element by calling FindElementsByCssSelector(css) of either the parentElement or the Driver
var candidates = WaitToFindElements(findFunc, css, waitInMills);
#if (STEP_BY_STEP)
Console.WriteLine("There are {0} candidates selected by '{1}'", candidates.Count, css);
#endif
if (Identifier.IsCollection())
{
//Store the filters if it is not null, otherwise use the last filters
lastFilters = filters ?? lastFilters;
if (lastFilters == null)
{
throw new NullReferenceException();
}
var filtered = candidates.Where(lastFilters);
lastFoundElement = filtered.FirstOrDefault();
}
else
{
lastFoundElement = candidates.FirstOrDefault(item => item.Text.Equals(Identifier.Value()));
}
}
//When CSS select one IWebElement, then filter is ignored
//Notice the GenericWait.Until() would keeps running until timeout or no Exception is thrown
else
{
Func <string, IWebElement> find = (parentElement == null)
? (Func <string, IWebElement>)DriverManager.FindElementByCssSelector
: parentElement.FindElementByCss;
lastFoundElement = GenericWait <IWebElement> .TryUntil(() => find(css),
x => x != null& x.IsValid(), ImmediateWaitToFindElement);
}
//if(lastFoundElement == null)
// throw new NoSuchElementException("Failed to find Element by CSS: " + css);
//Keeps the moment of this opertion
//lastTick = Environment.TickCount;
return(lastFoundElement);
}
