Check if integer == null

Question

I want to check if my Listentry = null but I don't know how.

Note: ID is a Integer

Here is my Code

if(MeineGaeste[i].ID !=null)
{
    i++;
}
else
{
    MeinGast.ID = i++;
    test = false;
}

Solution 1

As stated, an int cannot be null. If a value is not set to it, then the default value I believe is zero. You can do a check for 0 if that is what you think it is being set to...

Otherwise if you are keen on avoiding nullable integers, you would have to turn it into a string and then perform the check.

String.IsNullOrEmpty(ID.ToString());

Which returns a boolean so you can stick it into an if statement.

Solution 2

An int cannot be null. On the other hand a nullable int, int?, can be. That being said the check that you want to do is meaningless.

Changing the type of ID from int to int?, the check you do has a meaning and the compiler wouldn't complain about it.

Solution 3

you can use this ID.HasValue it return true when there is a value and false if null