.net - Azure函数自定义类请求正文 - 无无参数构造函数/无效的转换字符串 -> guid

Question

我有一个 azure 的函数，看起来像这样:

    [FunctionName("AddMaterial")]
    public static async Task<IActionResult> Run([HttpTrigger(AuthorizationLevel.Function, "post", Route = null)]AddMaterialCommand command, 
        ILogger log, [Inject(typeof(IMediator))]IMediator mediator)
    {
        log.LogInformation("AddMaterial Function is processing a request");

        var events = await mediator.Send(command);
        if (events != null)
        {
            await mediator.Publish(events);
            return (ActionResult)new OkObjectResult(events);
        }
        return new BadRequestObjectResult(new { message = "Please check that WarehouseId, RollPoNumber, RollNumber, Location and RollWeight are included in request" });
    }

此函数使用自定义对象 AddMaterialCommand 作为每个 the docs 的请求.

自定义对象类看起来像这样:

{
    [DataContract]
    public class AddMaterialCommand : IRequest<EventList>
    {
        [DataMember]
        public Guid WarehouseId { get; set; } 
        [DataMember]
        public int RollPoNumber { get; set; }
        [DataMember]
        public DateTime? DateRecieved { get; set; }

        public AddMaterialCommand(Guid warehouseId, int rollPoNumber,  DateTime dateRecieved)
        {
            WarehouseId = warehouseId;
            RollPoNumber = rollPoNumber;
            Location = location;
            DateRecieved = dateRecieved;
        }
}

当发布到函数时，它会抛出此错误:

Executed 'AddMaterial' (Failed, Id=d7322061-c972-4e93-83cd-4d0313d26e86) [9/12/2018 8:59:46 PM] System.Private.CoreLib: Exception while executing function: AddMaterial. Microsoft.Azure.WebJobs.Host: Exception binding parameter 'command'. System.Private.CoreLib: No parameterless constructor defined for this object.

当我添加无参数构造函数时(为什么需要这样做？)，它会失败并出现以下错误:

Executed 'AddMaterial' (Failed, Id=973cd363-19d6-49a3-a2eb-759f30c284bb) [9/12/2018 9:01:27 PM] System.Private.CoreLib: Exception while executing function: AddMaterial. Microsoft.Azure.WebJobs.Host: Exception binding parameter 'command'. System.Private.CoreLib: Invalid cast from 'System.String' to 'System.Guid'.

这是怎么回事？

我最好的猜测是请求的正文没有被读取，并且空值引发了无效的强制转换异常。我仍然不明白为什么我需要一个无参数的构造函数。在使用 [FromBody] 绑定(bind)时，在迁移到 azure 函数之前，我没有遇到此问题，但我认为我无法将该绑定(bind)与 azure 函数一起使用。

Answer 1

我最终只是用 httpRequestMessage 替换了自定义类，并在函数中创建了命令，如下所示

dynamic command = await req.Content.ReadAsAsync<AddMaterialCommand>();

仍然希望仅使用自定义类作为函数的参数，但是哦，好吧。