Question

I am facing inconsistent null value reference errors while I am trying to store my values from a serialized class object.

if ( item.current_location.city!=null )
{
    var city = item.current_location.city.Select(i => i.ToString());
}

In the above code snippet, successful insertion takes place even if any index in item array has null values. But it throws exception in some cases,which I don’t think can be distinguished in any manner from other cases( when the value is null)

Answer 1

item could be null as well

current_location could be null as well,

not only city.

This would help

if (item != null && 
    item.current_location != null && 
    item.current_location.city != null) {
    ...
} 

EDIT:

Note: This code works, since c# implements a so-called shortcut-evaluation of Boolean expressions. If item should be null, the rest of the expression would not be evaluated. If item.current_location should be null, the last term would not be evaluated.

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(I do not see any insertion in the code above.)

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Starting with C#6.0 you can use the null propagation operator (?):

var city = item?.current_location?.city?.Select(i => i.ToString());
if (city != null) {
     // use city ...
}