CODEWITHSUNDEEP
asp.netasp.net-web-apiodata
mort0124
mort0124

Reputation: 21

OData paging with expand issue

I'm using OData v5/Web API 2.2 to create an endpoint that will return a list of employees from each company.

My problem occurs when I try to implement server-side paging while also using the OData $expand property. When I try to make a call to

http://localhost:60067/Companies?$expand=Employees

I get an error that says "Could not find a property named 'Employees' on type 'System.Web.OData.Query.Expressions.SelectAllAndExpand_1OfCompanyApiModel'"

However, when I removed the EnableQuery attribute the call to the endpoint or when I didn't expand it works as expected. Does anyone have an idea of what I am doing wrong? I've been googling this for a while but haven't found anything.

Here are some code snippets -

Data Models:

public class CompanyApiModel
{
    [Key]
    public Guid CompanyGuid { get; set; }
    [Required]
    public string Name { get; set; }
    // other properties
    public List<EmployeeApiModel> Employees { get; set; }
}

public class EmployeeApiModel
{
    [Key]
    public Guid EmployeeGuid { get; set; }
    [Required]
    public string Name { get; set; }
    // other properties
}

CompaniesController.cs:

[EnableQuery(PageSize = 10)] // If I comment this out everything works
//[EnableQuery] // This fails as well
public IHttpActionResult Get(ODataQueryOptions<CompanyApiModel> queryOptions)
{
    var companies = GetCompanies(queryOptions);
    return Ok(companies);
    // return Ok(companies.AsQueryable()); // This doesn't work either
}

WebApiConfig.cs:

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        config.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always;  

        var routingConventions = ODataRoutingConventions.CreateDefault();
        routingConventions.Insert(0, new OptionsRoutingConvention());
        config.MapODataServiceRoute("odata", null, GetEdmModel(), new DefaultODataPathHandler(), routingConventions);


        // below code allows endpoints to respond with either XML or JSON, depending on accept header preferences sent from client 
        // (default in absence of accept header is JSON)
        var odataFormatters = ODataMediaTypeFormatters.Create();
        config.Formatters.InsertRange(0, odataFormatters);

        config.EnsureInitialized();

    }

    public static IEdmModel GetEdmModel()
    {
        ODataConventionModelBuilder builder = new ODataConventionModelBuilder();
        builder.Namespace = "Demos";
        builder.ContainerName = "DefaultContainer";

        builder.EntitySet<CompanyApiModel>("Companies");
        builder.EntitySet<EmployeeApiModel>("Employees");

        var edmModel = builder.GetEdmModel();
        return edmModel;
    }
}

Upvotes: 0

Views: 947

Answers (2)

mort0124
mort0124

Reputation: 21

Figured out the problem. We were overriding the EnableQuery attribute somewhere in our code and calling it EnableMappedQuery and applying it to the controller. Thus instead of having [EnableQuery(PageSize = 10)] I should have had [EnableMappedQuery(PageSize = 10)].

Upvotes: 2

Fan Ouyang
Fan Ouyang

Reputation: 2132

EnableQuery Attribute do many works, 

1. it will validate the queryoption for you.
2. it will apply the queryoption for you.
3. it can add some querysettings like PageSize.

Your scenario not working is because your GetCompanies is already applied the queryoption, so when EnableQuery get the result and apply the queryoption again, it fails, it can't find the expand property, my suggestion is just return original Company and let EnableQuery do the reset of work for you, ODataQueryOption in parameter is also not needed.

If you realy do some custom work in GetCompanies and don't need EnableQuery to apply for you, you can add PageSize in ODataQuerySettings when you call method ODataQueryOptions.ApplyTo(IQueryable, ODataQuerySettings).

Upvotes: 1

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