How do I use the '?' operator in mvc?

I have an MVC application and I want to use this ? option.

Please tell me how I can do this. I have written:

int? isfeature;

but, while inserting the value in database, how do I 开发者_如何学Gouse it?

It is giving following error:

Cannot convert from 'int?' to 'int'.

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int? is a shorthand for Nullable<int>, which means that the value can either be an integer or null. To convert a Nullable<int> to an int, use

int? ni = 2;
int i = (int)ni;

or

int? ni = 2;
int i = ni.Value;

This will throw an exception if the value is null, so you can also use

int? ni = null;
int i = ni ?? 0;

to use 0 as a default value.

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do you mean something like this?

$foo = $foo == 1 ? $foo : $bar;

Because I don't understand much of your question...