[VB.NET] Behavior when writing a Nullable type with a one-liner If
Returns Nothing with Nullable type on the left side and one-liner If on the right side
Such a source
Since it is an example, the text remains Nothing, and the return value when it is not Nothing is appropriately set to 100.
'Explicitly initialize for clarity. Dim text As String = Nothing Dim value As Integer? = If(text Is Nothing, Nothing, 100)
You want the return value to be Nothing or some other value (100 in the example above).
Well, it’s rare, but there are occasional cases where you want to do something like this.
You can write it gently in If-Else, but it’s a waste of lines and it doesn’t look good, so I just want to write it in one liner.
what will happen
If it is not Nothing, it is fine, and if it is ** Nothing, 0 ** is returned.
You can see why by writing the same code in C #.
string text = null; int? value = text == null ? default(int) : 100; //I can't write this. // int? value = text == null ? null : 100;
Nothing has the function of default
How to write
There is no choice but to give up writing with one liner.
Dim value As Integer? If text Is Nothing Then value = Nothing Else value = 100 End If
Well, the number of lines has increased and it doesn’t look good. .. ..
By the way, the code written in one liner is explicitly typed without type inference, but if you try to type infer, it will be a normal int type, so be careful.
I’ve been thinking about writing something for a long time, and I sometimes submit a report using Qiita in another case, so I’d like to get used to writing a little story …
(Because I don’t have such a big technical ability …)