Iterate over array/list inside a linq query

Question

I'm trying to use this linq query to check if certain object's netIds are null, blank, or otherwise empty.

var badData = FileSignatures.Drive.Public.Where(
    e => String.IsNullOrWhiteSpace(
        e.NetworkBlock?.Select(n => n.netId)) &&
         String.IsNullOrWhiteSpace(
             e.WiFiBlock?.netId) &&
             String.IsNullOrWhiteSpace(
                 e.BluetoothBlock?.netId))
    .ToList();

WiFiBlock and BluetoothBlock are both just single objects so the above should work.

However, NetworkBlock is an array of objects so I need to figure out how to iterate through each object in NetworkBlock and check it's netId.

Is it possible to do something like that inside a linq query?

Thanks!

e.NetworkBlock?.Any(n => String.IsNullOrWhitespace(n.Id)) or something of that nature. It's an enumeration; you can do anything with it in that lambda that you could anywhere else. — 15ee8f99-57ff-4f92-890c-b56153
– 15ee8f99-57ff-4f92-890c-b56153, Commented Oct 7, 2019 at 15:44

Ousmane D. · Accepted Answer · 2019-10-07 15:51:44Z

2

Sure thing!

change this:

String.IsNullOrWhiteSpace(
        e.NetworkBlock?.Select(n => n.netId))

to this:

e.NetworkBlock?.Any(n => String.IsNullOrWhiteSpace(n.netId)) ?? false // or true depending on criteria

or using All depending on your criteria.

full code:

var badData = FileSignatures.Drive.Public.Where(
    e => (e.NetworkBlock?.Any(n => String.IsNullOrWhiteSpace(n.netId)) ?? false) &&
         String.IsNullOrWhiteSpace(
             e.WiFiBlock?.netId) &&
             String.IsNullOrWhiteSpace(
                 e.BluetoothBlock?.netId))
    .ToList();

edited Oct 7, 2019 at 15:51

answered Oct 7, 2019 at 15:45

Ousmane D.

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3 Comments

SkyeBoniwell Over a year ago

Thanks! That looks like it should work but I am getting "cannot convert from bool to string".

Ousmane D. Over a year ago

@SkyeBoniwell that shouldn't be with the code I've introduced. look carefully elsewhere in your code.

SkyeBoniwell Over a year ago

Oh ok, I know that 'false' is a boolean, so I thought it might have been trying to convert that to a string. It was because I forgot an open parentheses!

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