Selenium with C# 40 - How to create Custom Expected Conditions class methods - explained with code

How to create Custom Expected Conditions class methods - explained with code.
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How to create Custom expected condition?
Expected Condition class methods :
Supplies a set of common conditions that can be waited
All methods in this class are static
Some of the methods are overloaded methods
We can write custom Expected conditions method

Why we need to create custom Expected Condition?
We need custom expected conditions when the built-in Selenium WebDriver expected conditions are not sufficient for creating complex conditions.

How To Write Custom Expected condition?
The Until method of WebDriverWait class uses ExpectedConditions to wait for a particular condition(Represented by a method/lambda expression) to be met.
The Until method waits till one of the following events occurs:
The condition definition returns neither null nor false.
The condition definition returns an exception that is not in the list of ignored exception types.
The timeout period defined during WebDriverWait object creation expires.

A custom ExpectedCondition can be written in 3 ways:

1. By defining a named method that has exactly one parameter of type IWebDriver and returns a value.
2. By writing a lambda expression that accepts exactly one parameter of type IWebDriver and returns a value.
3. By defining a method which returns a value of type Func IWebDriver, TResult


private IWebElement WaitFor(IWebDriver driver)
{
IWebElement element = driver.FindElement(By.ClassName("ContactUs"));
if (element.Displayed && element.Enabled && element.Text.Contains("C#"))
{
return element;
}
return null;
}
wait.Until IWebElement(WaitFor);

By writing a lambda expression that accepts exactly one parameter of type IWebDriver and returns a value.

wait.Until(d =
{
IWebElement element = driver.FindElement(By.ClassName("ContactUs"));
if (element.Displayed && element.Enabled && element.Text.Contains("C#"))
{
return element;
}
return null;
});


By defining a method which returns a value of type Func IWebDriver, TResult

public class CustomExpectedConditions
{
public static Func IWebDriver, bool WaitForElementToContainText(By by)
{
myCustomCondition = driver =
{
IWebElement element= driver.FindElement(by);
if (element != null)
{
if (element.Displayed && element.Enabled && element.Text.Contains("C#"))
return true;
else
return false;
}
return false;
};

By defining a method which returns a value of type Func IWebDriver, TResult

wait.Until(CustomExpectedConditions.WaitForElementToContainText(By.ClassName("ContactUs")));

Possible Interview Question on selenium webdriver custom expected conditions class :
Can we create the custom expected conditions?
How to create the custom expected conditions?
Which are the different ways to create custom expected conditions?