LinQ Item Present Validation

Question

Currently I do this to validate if an item is present in the list

var wifiSSID = userLocation.LocationWiFiSSIDs.Where(x => x.WiFiSSID == attendanceDto.WiFiSSID).FirstOrDefault();
if (IsWiFiSSIDEnabled && wifiSSID == null)
{
    throw new ApplicationException(ErrorMessages.InvalidWiFiSSID);
}

Can I write this in better way? With Any or Contains?

har07 · Accepted Answer · 2017-03-25T06:44:04.050

2

Assuming that wifiSSID is only used for validation in your code, then you can use Any() as follows :

if (IsWiFiSSIDEnabled && !userLocation.LocationWiFiSSIDs.Any(x => x.WiFiSSID == attendanceDto.WiFiSSID)
{
    throw new ApplicationException(ErrorMessages.InvalidWiFiSSID);
}

This way userLocation will be checked only if IsWiFiSSIDEnabled is true.

edited Mar 25 '17 at 06:44

answered Mar 25 '17 at 06:40

har07

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Is there any specific reason to use Any instead of All? – jitender Mar 25 '17 at 06:43
Is there any difference between Any() and All()? – Krishnandu Sarkar Mar 25 '17 at 07:22
1

@KrishnanduSarkar Not much besides readability (which also varies from person to person, considering one's familiarity of a method over the other, for example. I'm not against dotNet's comment here btw) : [LINQ: Not Any vs All Don't](http://stackoverflow.com/questions/9027530/linq-not-any-vs-all-dont) – har07 Mar 25 '17 at 08:53
Thanks a lot @har07 :) – Krishnandu Sarkar Mar 25 '17 at 11:54

score 2 · Answer 2 · answered Mar 25 '17 at 06:42

2

Use all

if (IsWiFiSSIDEnabled && userLocation.LocationWiFiSSIDs.All(x => x.WiFiSSID != attendanceDto.WiFiSSID)
{
    throw new ApplicationException(ErrorMessages.InvalidWiFiSSID);
}

answered Mar 25 '17 at 06:42

jitender

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LinQ Item Present Validation

2 Answers2