在asp.netcore中上傳圖片api

我正在構建一個 api 來將影像存盤為機器模型類的一部分，以便在 xamarin.forms 中使用它，所以這是機器類：

 public class Machine
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.None)]
        public string Machine_Qr { get; set; }
        public string Machine_Name { get; set; }
        [NotMapped]
        public string Image { get; set; }
}

這是機器控制器：

public class MachineController : ControllerBase
    {
        private readonly DataContext _context;
        private IHostingEnvironment _hostingEnvironment;

        public MachineController(DataContext context, IHostingEnvironment environment)
        {
            _context = context;
            _hostingEnvironment = environment ?? throw new ArgumentNullException(nameof(environment));



        }
        [HttpPost]
        public async Task<ActionResult<Machine>> Create(Machine machine)
        {
            if (ModelState.IsValid)
            {
                var files = HttpContext.Request.Form.Files;
                foreach (var Image in files)
                {
                    if (Image != null && Image.Length > 0)
                    {

                        var file = Image;
                        var uploads = Path.Combine(_hostingEnvironment.WebRootPath, "uploads\\img\\Machines");

                        if (file.Length > 0)
                        {
                            var fileName = ContentDispositionHeaderValue.Parse
                                (file.ContentDisposition).FileName.Trim('"');

                            System.Console.WriteLine(fileName);
                            using (var fileStream = new FileStream(Path.Combine(uploads, file.FileName), FileMode.Create))
                            {
                                await file.CopyToAsync(fileStream);
                                machine.Image = file.FileName;
                            }


                        }
                    }
                }

                _context.Add(machine);
                await _context.SaveChangesAsync();

            }
            return CreatedAtAction(nameof(PostMachine), new { id = machine.Machine_Qr }, machine);
        }

但是，當我嘗試以大搖大擺的方式測驗 api 時，我收到了這條訊息：

System.InvalidOperationException: Incorrect Content-Type: application/json
   at Microsoft.AspNetCore.Http.Features.FormFeature.ReadForm()
   at Microsoft.AspNetCore.Http.DefaultHttpRequest.get_Form()
   at WebApi.Controllers.MachineController.Create(Machine machine) in C:\Users\amyra\source\repos\WebApi\Controllers\MachineController.cs:line 35

machineController 第 35 行是：

 var files = HttpContext.Request.Form.Files;

uj5u.com熱心網友回復：

您應該在課堂上收到 Image 作為IFormFile屬性Machine

[NotMapped]
public IFormFile Image { get; set; }

然后[FromForm]在您的請求中使用屬性

[HttpPost]
public async Task<ActionResult<Machine>> Create([FromForm] Machine machine)

現在您可以洗掉這些行

var files = HttpContext.Request.Form.Files;
                foreach (var Image in files)
                {
                    
                }

并直接使用machine.Image您通過 Swagger 上傳的

var file = machine.Image;
if (file != null && file.Length > 0)
{
    var fileName = ContentDispositionHeaderValue.Parse
                                
    (file.ContentDisposition).FileName.Trim('"');

    System.Console.WriteLine(fileName);
    using (var fileStream = new FileStream(Path.Combine(uploads, file.FileName), FileMode.Create))
        {
             await file.CopyToAsync(fileStream);
        }
}

標籤：网 asp.net 核心 xamarin.forms

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