Linq Method does not contain a definition for (Contains)

Question

I have an array of ServiceGrid items called services, the relevant properties are shown below:

svcId / svcName / svcBillingRate/ and more....
5 / serviceA / 10.00 .
19 / serviceB / 19.25
11 / serviceC / 24.00
17 / serviceD / 4.50
2 / serviceE / 9.00

I also have a hashset<int> addOnOptions that has a number of svcIds, say 11 and 17

My objective is to end up with:

5 / serviceA / 10.00
19 / serviceB / 19.25
2 / serviceE / 9.00

var theSelectedAddOns = addOnOptions.ToList().Where(x => new[] {services.ToList()}.Contains(x));

Not sure what to make of this error message:

'List<ServiceGrid>[]' does not contain a definition for 'Contains' and the best extension method overload 'MemoryExtensions.Contains<int>(ReadOnlySpan<int>, int)' requires a receiver of type 'ReadOnlySpan<int>'

I am out of ideas on how to proceed here.

Answer 1

var result = services.Where(svc => !addOnOptions.Any(aoo => aoo == svc.svcId));

This will give the answer that your sample data requires.

Your code with 'contains' implies that you want the inverse of this, remove the not operator

var result = services.Where(svc => addOnOptions.Any(aoo => aoo == svc.svcId));

Answer 2

Hi @MyLadys-4900,

I also have a hashset<int> addOnOptions that has a number of svcIds, say 11 and 17

My objective is to end up with:

5 / serviceA / 10.00
19 / serviceB / 19.25
2 / serviceE / 9.00

var theSelectedAddOns = addOnOptions.ToList().Where(x => new[] {services.ToList()}.Contains(x));

From your description, I assume you want to filter the service array based on the addOnOptions value. If that is the case, the LINQ query statement should like this:

var services = new ServiceGrid [] {   
    new ServiceGrid() { svcId = 5, svcName = "serviceA", svcBillingRate = 10.00M },  
    new ServiceGrid() { svcId = 19, svcName = "serviceB", svcBillingRate = 19.25M },  
    new ServiceGrid() { svcId = 11, svcName = "serviceC", svcBillingRate = 24.00M },  
    new ServiceGrid() { svcId = 17, svcName = "serviceD", svcBillingRate = 4.5M },  
    new ServiceGrid() { svcId = 2, svcName = "serviceE", svcBillingRate = 9.00M }  
};  
var addOnOptions = new HashSet<int> { 11, 17 };  
//Find service from the array which its svcId not in the addOnOptions.  
var result = services.ToList().Where(c => !addOnOptions.ToList().Contains(c.svcId)).ToList();  
//Find service from the array which its ID in the options.  
var result2 = services.ToList().Where(c => addOnOptions.ToList().Contains(c.svcId)).ToList();  

The result like this:

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Best Regards,
Dillion