Question

我希望使用F＃WSDL Type Provider。要调用我正在使用的Web服务，我需要将我的客户端凭据附加到System.ServiceModel.Description.ClientCredentials。

这是我的C＃代码：

var serviceClient = new InvestmentServiceV1Client.InvestmentServiceV1Client();

foreach (ClientCredentials behaviour in serviceClient.Endpoint.Behaviors.OfType<ClientCredentials>())
{
    (behaviour).UserName.UserName = USERNAME;
    (behaviour).UserName.Password = PASSWORD;
    break;
}

这是我到目前为止的F＃代码：

let client = new service.ServiceTypes.InvestmentServiceV1Client()
let xxx = client.Endpoint.Behaviors
|> Seq.choose (fun p -> 
    match box p with   
    :?   System.ServiceModel.Description.ClientCredentials as x -> Some(x) 
    _ -> None) 
|> (System.ServiceModel.Description.ClientCredentials)p.UserName.UserName = USERNAME

F＃等效于System.Linq.Enumerable.OfType<T>还是应该使用原始OfType<T>？

Answer 1

我想这个问题主要是关于break构造，这在F＃中是不可用的。好吧，代码实际上只是为集合的第一个元素设置用户名和密码（如果集合为空，则为none）。如果您将集合转换为F＃列表，则可以使用模式匹配轻松完成此操作：

// Get behaviours as in C# and convert them to list using 'List.ofSeq'
let sc = new InvestmentServiceV1Client.InvestmentServiceV1Client()
let behaviours = sc.Endpoint.Behaviors.OfType<ClientCredentials>() |> List.ofSeq

// Now we can use pattern matching to see if there is something in the list
match behaviours with
| behaviour::_ ->
    // And if the list is non-empty, set the user name and password
    behaviour.UserName.UserName <- USERNAME
    behaviour.UserName.Password <- PASSWORD
| _ -> ()

Answer 2

我认为你已经实现了 .OfType（）的F＃等价物。为了模拟 break 语句，您可以像Tomas在答案中所做的那样（匹配列表），或者调用 Seq.head （如果没有剩余元素则抛出），或者你可以这样做：

let xxx = 
    client.Endpoint.Behaviors
    |> Seq.choose (function
        | :? System.ServiceModel.Description.ClientCredentials as x -> Some x
        | _ -> None ) 
    |> Seq.tryPick Some

match xxx with
| Some behavior -> ... // First element of required type found
| None -> ...          // No elements of required type at all in sequence

System.Linq.Enumerable.OfType <t> - 是否有F＃方式？</t>

2 个答案: