MS Search API: how to limit the number of matches to just the top X results?

Question

How do I limit the number of results coming back from the MS Search Api? Here's what the code looks like:

  public async Task<string> Search()
    {
        var ApplicationClientID = Environment.GetEnvironmentVariable("CLIENT_ID");
        var ApplicationClientSecret = Environment.GetEnvironmentVariable("CLIENT_SECRET");
        var AzureTenantID = Environment.GetEnvironmentVariable("TENANT_ID");
        string[] scopes = new[] { "https://graph.microsoft.com/.default" };

        // using Azure.Identity;
        var options = new ClientSecretCredentialOptions
        {
            AuthorityHost = AzureAuthorityHosts.AzurePublicCloud,
        };

        try
        {
            var clientSecretCredential = new ClientSecretCredential(
                AzureTenantID, ApplicationClientID, ApplicationClientSecret, options);
            var graphClient = new GraphServiceClient(clientSecretCredential, scopes, "https://graph.microsoft.com/v1.0");
            Console.WriteLine($"searchQuery :{searchQuery}");
            var requestBody = new Microsoft.Graph.Search.Query.QueryPostRequestBody
            {
                Requests = new List<SearchRequest>
                    {
                        new SearchRequest
                        {
                            EntityTypes = new List<EntityType?>
                            {
                                EntityType.DriveItem,
                            },
                            Query = new SearchQuery
                            {
                                QueryString = this.searchQuery,
                            },
                            Fields = new List<string>
                            {
                                "driveId",
                                "listItemId",
                                "author",
                                "title",
                                "url",
                                "rank"
                            },
                            QueryAlterationOptions = new SearchAlterationOptions
                            {
                                EnableSuggestion = true,
                                EnableModification = true,
                            }
                            , Region ="US"
                        },
                    },
            };

         
            var searchResults = await graphClient.Search.Query.PostAsync(requestBody).ConfigureAwait(false);
            //return searchResults;
            var jsonResults = ExtractDriveItemDetails(searchResults);
            return jsonResults;
        }
        catch (Exception ex)
        {
            log.LogError(ex.Message);
            return null;
        }
    }

The Environmment / Setup

I'm using MS Graph 1.0. Here are the references from the csproj file:

<PackageReference Include="AutoMapper" Version="12.0.1" />
<PackageReference Include="AutoMapper.Extensions.Microsoft.DependencyInjection" Version="12.0.1" />
<PackageReference Include="Azure.Identity" Version="1.9.0" />
<PackageReference Include="Microsoft.Azure.Functions.Extensions" Version="1.1.0" />
<PackageReference Include="Microsoft.NET.Sdk.Functions" Version="4.1.1" />
<PackageReference Include="Microsoft.Azure.Services.AppAuthentication" Version="1.6.0" />
<PackageReference Include="Microsoft.Graph" Version="5.18.0" />
<PackageReference Include="Microsoft.Graph.Core" Version="3.0.9" />
<PackageReference Include="Microsoft.Identity.Client" Version="4.54.1" />  

What I've tried:

I've tried to change the SearchQuery to look like this:

 Query = new SearchQuery
 {
      QueryString = this.searchQuery,
      Top = 4
 },

And this:

 Query = new SearchQuery
 {
      QueryString = this.searchQuery,
      Count = 4
 },

Neither work.

I also read about the EnableTopResults option but it only seems to be available for messages. https://learn.microsoft.com/en-us/graph/api/resources/searchrequest?view=graph-rest-1.0

Can you point me in the right direction?
Thank you.

Answer 1

What about the size property. It defines the number of items per page to be retrieved.

new SearchRequest
{
    EntityTypes = new List<EntityType?>
    {
        EntityType.DriveItem,
    },
    Query = new SearchQuery
    {
        QueryString = this.searchQuery,
    },
    Size = 4,
    Fields = new List<string>
    {
        "driveId",
        "listItemId",
        "author",
        "title",
        "url",
        "rank"
    },
    QueryAlterationOptions = new SearchAlterationOptions
    {
        EnableSuggestion = true,
        EnableModification = true,
    }, 
    Region ="US"
}