Proper usage of Hl7.Fhir.Rest.SearchParams.Add for multiple values of the same param-Name

Question

https://github.com/CareEvolution/fhir-net-api/blob/multiversions/src/Hl7.Fhir.Core/Rest/SearchParams.cs#L107

    /// <summary>
    /// Add a parameter with a given name and value.
    /// </summary>
    /// <param name="name">The name of the parameter</param>
    /// <param name="value">The value of the parameter as a FHIR datatype or Resource</param>
    /// <returns>this (Parameters), so you can chain AddParameter calls</returns>
    public SearchParams Add(string name, string value)
    {

I am trying to figure out the proper use of the SearchParams.Add

when I have an "OR" on the same search-param-NAME.

Example:

http://hapi.fhir.org/baseR4/Appointment?_count=555&patient=Patient/40a7788611946f04,Patient/113798

To capture this, should I do:

                SearchParams sp1 = new SearchParams();
                sp1.Add("patient", "Patient/40a7788611946f04");
                sp1.Add("patient", "Patient/113798");
                

Or:

                SearchParams sp2 = new SearchParams();
                sp2.Add("patient", "Patient/40a7788611946f04,Patient/113798");

Full bread crumb:

namespace Hl7.Fhir.Rest
    public class SearchParams

..

   <PackageReference Include="Hl7.Fhir.R4" Version="5.11.0" />

Answer 1

The former one is the right /better choice as you can add the values dynamically without concatenating explicitly to achieve your result.

SearchParams sp1 = new SearchParams();
sp1.Add("patient", "Patient/40a7788611946f04");
sp1.Add("patient", "Patient/113798");

But it does not allow to add "or" condition for patient parameters list through the below code execution var result = fhirClient.Search(sp1);

Alternate way

var sp2= new SearchParams();

string[] patientIds = new string[] { "Patient/40a7788611946f04", "Patient/113798", "Patient/783746" };

sp2.Add("patient", string.Join(",", patientIds));

sp2.Add("_count", "555");