如何修复：使用未分配的本地IWebElement变量

Question

For the following code,

IWebElement element; // = new WebElement();
try
{
    element = driver.FindElement(By...);
}
catch (Exception)
{
}
element.Click();

How to fix the error of Use of unassigned local variable ?

I know for the error of Use of unassigned local variable , the fix is to assign it with something initially, but I've tried new WebElement(); and new IWebElement(); but they didn't work for me.

Any help?

PS. I was trying in the catch statement to loop and find it, that's why I need the element declaration outside of try , and Click() after it.

Answer 1

The compiler helps to fix a bug. He's telling you that this will fail with a NullReferenceException at element.Click() if there was an exception during initialization of element . So he wants you to assign something in any case(or as default value). You have multiple options to fix...

Use the object after the initialization in the try :

try
{
    element = driver.FindElement(By...);
    element.Click();  // safe because there was no exception
}
catch (Exception)
{
    // empty catch is bad, log this at least
}

"Hide" the compiler error but let the potential bug live by assigning something to the variable:

IWebElement element = null;
try
{
    element = driver.FindElement(By...);
}
catch (Exception)
{
    // empty catch is bad, log this at least
}

element.Click(); // still a bug if there was an exception this will cause a NullReferenceException

this option is perfectly fine if you use if(element != null) element.Click(); instead.

Or you could use the catch / finally to assign something (imo worst option here):

IWebElement element;
try
{
    element = driver.FindElement(By...);
}
catch (Exception)
{
    element = null;
}

But then you have to check for null , either with if(element != null) or with:

element?.Click(); // if not null Click is called