don't understand this - System.Nullable(Of Integer))


I have a function automatically created for me by visual studio. the function includes this parameter

  ByRef JobID As System.Nullable(Of Integer))

This parameter is given a value during the function that i need to access. I don't understand what System.Nullable(Of Integer)) means

Please can you show me how i declare a variable that i can pass into this function and how i can then access its value

what does the system.nullable mean?

Thanks a lot
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It's a brilliant feature:

it will allow you to check if a value is nothing which never really worked for value types like integer

So you can e.g. create a sub like

Public sub testing (testVal as System.Nullable(integer))

'try to see if it has a value
if testVal.HasValue then ("so happy")
end if

end sub

call your sub like:
testing (nothing)
or testing (1)

in your sub you can get the value like

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Visual Basic.NET

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