在空的IQueryable上进行SingleResult.Create的Odata序列化错误 [英] Odata serialization error for SingleResult.Create on an empty IQueryable

问题描述

我正在使用OData v4，并试图使一个非常简单的控制器正常工作:

I'm using OData v4 and trying to get a really simple controller working:

控制器:

public class ProductController : ODataController
{
readonly MasterDataEntities db = new MasterDataEntities();

[EnableQuery(PageSize = MaxPageSize)]
public IQueryable<Product> Get()
{
    return db.Products;
}

[EnableQuery]
public SingleResult<Product> Get([FromODataUri] string key)
{
    return SingleResult.Create(db.Products.Where(p => p.Code == key));
}
}

WebApiConfig:

WebApiConfig:

ODataModelBuilder builder = new ODataConventionModelBuilder();
builder.EntitySet<Product>("Product");
builder.EntityType<Product>().HasKey(p => p.Code);
config.MapODataServiceRoute("ODataRoute", null, builder.GetEdmModel());

当我致电servicelocation/Product('abc')

When I make a call to servicelocation/Product('abc')

如果abc是有效的代码，我会得到一个很好的JSON序列化的Product对象

If abc is a valid code, I get a nicely JSON serialized Product object back

如果abc是无效代码，则会出现以下错误:

If abc is an invalid code I get the following error:

'SingleResult`1'无法使用ODataMediaTypeFormatter进行序列化.

'SingleResult`1' cannot be serialized using the ODataMediaTypeFormatter.

在System.Web.OData.Formatter.ODataMediaTypeFormatter.GetSerializer(类型类型，对象值，IEdmModel模型，ODataSerializerProvider serializerProvider)

at System.Web.OData.Formatter.ODataMediaTypeFormatter.GetSerializer(Type type, Object value, IEdmModel model, ODataSerializerProvider serializerProvider)

我已经花了2天的时间寻找解决方案，但似乎没人能解决这个问题?

I've spent 2 days looking for a solution now but it seems nobody else gets this issue?

推荐答案

请在此处中查看此解决方法>

please see this workaround here

一种变通方法，它将识别SingleResult类型何时不包含任何结果，并将其替换为404，而不是引发SerializationException.

A workaround that will recognise when a SingleResult type does not contain any results and replace it with a 404 instead of throwing a SerializationException.

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