F# 无财产'；HasValue'；ODataService类型提供程序的可为null的int存在

我正在尝试使用Netflix的ODataService类型提供程序。这很好：

type internal NetflixData = ODataService<"http://odata.netflix.com/Catalog/">
let internal NetflixContext = NetflixData.GetDataContext()

let godzillamovies = query { for t in NetflixContext.Titles do 
                             where (t.Name.Contains "Godzilla")
                             select (t.Name, t.ReleaseYear)
                           } |> Seq.toList

我遇到了以下错误：

<?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"yes\"?>
<error xmlns=\"http://schemas.microsoft.com/ado/2007/08/dataservices/metadata\">
  <code></code>
  <message xml:lang=\"en-US\">No property 'HasValue' exists in type 'System.Nullable`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]' at position 45.</message>
</error>

HasValue对于可为null的整数不存在？自从何时？

#r“FSharp.Data.TypeProviders”
#r "FSharp.Data.TypeProviders"
#r "System.Data.Services.Client"

open Microsoft.FSharp.Data.TypeProviders
open Microsoft.FSharp.Linq.NullableOperators

type internal NetflixData = ODataService<"http://odata.netflix.com/Catalog/">
let internal NetflixContext = NetflixData.GetDataContext()

NetflixContext.DataContext.SendingRequest.Add(fun e -> printfn "%A" e.Request.RequestUri)

// http://odata.netflix.com/Catalog/Titles()?$filter=substringof('Godzilla',Name) and (ReleaseYear ne null)&$select=Name,ReleaseYear
let godzillamovies = query { for t in NetflixContext.Titles do 
                             where (t.Name.Contains "Godzilla")
                             where (t.ReleaseYear ?<>? System.Nullable())
                             select (t.Name, t.ReleaseYear)
                           } |> Seq.toList

#r“系统、数据、服务、客户端”
打开Microsoft.FSharp.Data.TypeProviders
打开Microsoft.FSharp.Linq.NullableOperators
键入内部NetflixData=ODataService
让内部NetflixContext=NetflixData.GetDataContext（）
NetflixContext.DataContext.SendingRequest.Add（趣味e->printfn“%A”e.Request.RequestUri）
// http://odata.netflix.com/Catalog/Titles（）？$filter=substringof（'Godzilla'，Name）和（ReleaseYear ne null）&$select=Name，ReleaseYear
让godzillamovies=query{for NetflixContext.Titles中的t
其中（t.Name.Contains“哥斯拉”）
其中（t.ReleaseYear？？System.Nullable（））
选择（t.Name，t.ReleaseYear）
}|>顺序列表

我不得不将选择切换到

select（t.Name，t.ReleaseYear.Value）

但是很好，谢谢。

#r "FSharp.Data.TypeProviders"
#r "System.Data.Services.Client"

open Microsoft.FSharp.Data.TypeProviders
open Microsoft.FSharp.Linq.NullableOperators

type internal NetflixData = ODataService<"http://odata.netflix.com/Catalog/">
let internal NetflixContext = NetflixData.GetDataContext()

NetflixContext.DataContext.SendingRequest.Add(fun e -> printfn "%A" e.Request.RequestUri)

// http://odata.netflix.com/Catalog/Titles()?$filter=substringof('Godzilla',Name) and (ReleaseYear ne null)&$select=Name,ReleaseYear
let godzillamovies = query { for t in NetflixContext.Titles do 
                             where (t.Name.Contains "Godzilla")
                             where (t.ReleaseYear ?<>? System.Nullable())
                             select (t.Name, t.ReleaseYear)
                           } |> Seq.toList