[英]POST request vue C#
---編輯問題:---
我正在用 c# web 應用程序作為后端和 Vue 作為前端構建我的第一個網站。 我的 GET 和 DELETE 工作正常,但是當我想運行 POST 時出現問題,我無法完全理解如何修復..
據我的老師說,我的 Axios 連接看起來不錯,問題僅出在我的后端..
我想我想做的是以某種方式綁定模型,以便他們互相交談?
我的數據模型是 Sale.cs,我的視圖模型(來自 Vue)被稱為 SaleVM.cs
銷售.cs:
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
namespace Models
{
public class Sale
{
public enum Status
{
Started,
Ongoing,
Done,
Removed
}
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; } //++
[Required]
public string CustomerNumber { get; set; }
public int UserId { get; set; } //fk
[Required]
public string YourReference { get; set; }
public DateTime DateSold { get; set; }
public DateTime DateCreated { get; set; }
public DateTime? DateDone { get; set; }
public DateTime? DateEdited { get; set; }
public Status StatusId { get; set; }
public DateTime? DateDelivered { get; set; }
public virtual ICollection<SaleArticle> SaleArticles { get; set; }
public virtual User User { get; set; }
}
}
銷售VM:
using System.Collections.Generic;
namespace Models
{
public class SaleVM
{
public enum Status
{
Started,
Ongoing,
Done,
Removed
}
public int Id { get; set; }
public string Reference { get; set; }
public DateTime DateSold { get; set; }
public DateTime DateCreated { get; set; }
public Status StatusId { get; set; }
public int UserId { get; set; }
public virtual ICollection<ArticleRow> ArticleRows { get; set; }
public virtual SelectedCustomer SelectedCustomer { get; set; }
}
}
我想我沒有正確地制作它們,因為我只是猜測如何編寫它們。
最后是我的 SaleController:
{
[Route("api/[controller]")]
[ApiController]
public class SaleController : ControllerBase
{
private readonly DataContext _context;
public SaleController(DataContext context)
{
_context = context;
}
// POST: api/Sales/5
[HttpPost]
public async Task<ActionResult<Sale>> PostSale(SaleVM saleVM)
{
string customerNumber = (saleVM != null && saleVM.SelectedCustomer != null && Convert.ToInt32(saleVM.SelectedCustomer.CustomerNumber) > 0) ? saleVM.SelectedCustomer.CustomerNumber : "";
List<SaleArticle> saleArticles = new List<SaleArticle>();
if (saleVM != null && saleVM.ArticleRows != null && Convert.ToInt32(saleVM.ArticleRows) > 0)
{
foreach (var item in saleVM.ArticleRows)
{
saleArticles.Add(new SaleArticle()
{
ArticleNumber = item.ArticleNumber,
Price = item.SalesPrice,
Quantity = item.Quantity,
Description = item.Description,
Id = item.Name
});
}
}
//foreach (var saleVM in SaleVM)
//{
Sale sale = new Sale();
{
sale.CustomerNumber = saleVM.SelectedCustomer.CustomerNumber;
sale.YourReference = saleVM.Reference;
sale.SaleArticles = saleArticles;
sale.DateCreated = saleVM.DateCreated;
sale.DateSold = saleVM.DateSold;
sale.StatusId = (Sale.Status)saleVM.StatusId;
sale.UserId = saleVM.UserId;
};
_context.Sales.Add(sale);
//}
await _context.SaveChangesAsync();
return CreatedAtAction(nameof(GetSale), new { id = saleVM.Id }, saleVM);
}
}
}
我在 Visual Studio 中沒有收到任何錯誤消息,但是當我在郵遞員中嘗試代碼時,我收到狀態碼 500 內部服務器錯誤:
System.NullReferenceException:未將對象引用設置為對象的實例。 在 E37SalesApi.Controllers.SaleController.PostSale(SaleVM saleVM) 在 C:\\Users\\fadaka\\source\\repos\\E37SalesApi\\Controllers\\SaleController.cs:line 47 at lambda_method(Closure , Object) at Microsoft.Extensions.Internal.ObjectMethodExecutorAwaitable。 Awaiter.GetResult() at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.AwaitableObjectResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__AwaitedController|12Invoker0 invoker, ValueTask`1 actionResultValueTask) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker .Rethrow(ActionExecutedContextSealed context) 在 Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(Sta te& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync() ---從上一個拋出異常的位置的堆棧跟蹤結束---在Microsoft.AspNetCore.Mvc。 Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)的Infrastructure.ResourceInvoker.g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)在 Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger) 在 Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context) 在 Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware context.Invoke(HttpContext context)
我確實明白它說的是什么,只是我真的不明白如何修復它並使我的 POST 方法完全起作用。
我希望我清楚我的問題
我對編程非常陌生,發現很難在網上找到像我這樣的菜鳥可以理解的水平的信息,尤其是在 c# 和 vue 一起工作時。
如果我是你,我會在 PostSale 操作的第一行放置一個斷點並檢查模型的哪些部分為空。
您的 JSON 中的屬性應該與您的模型相匹配。 UserId、StatusId、DateCreated 和 DateSold 都很好,但沒有其他東西通過,因此 SelectedCustomer 將為空(很可能會導致您的問題)。
{
"customerNumber": "111",
"userId": 2,
"yourReference": "Referens namn",
"dateSold": "2020-03-01T00:00:00",
"dateCreated": "2020-03-01T00:00:00",
"dateDone": "2020-03-01T00:00:00",
"dateEdited": "2020-03-01T00:00:00",
"statusId": 2,
"dateDelivered": "2020-03-01T00:00:00"
}
應該與下面匹配,即有'
public class SaleVM
{
public enum Status
{
Started,
Ongoing,
Done,
Removed
}
public int Id { get; set; }
public string Reference { get; set; }
public DateTime DateSold { get; set; }
public DateTime DateCreated { get; set; }
public Status StatusId { get; set; }
public int UserId { get; set; }
public virtual ICollection<ArticleRow> ArticleRows { get; set; }
public virtual SelectedCustomer SelectedCustomer { get; set; }
}
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