.net core 基于multipart/form-data的文件上传，这里以图片上传为例

首先传递的数据格式大概如下：

然后就可以在后端获取数据了：直接上代码了哈：

[HttpPost]        ///分别获取 data数据和调用图片上传方法
public async Task<JsonResult> UploadDefault()
{
var data =Request.Form["data"];
var dataPosition=GetSortModel(data);  //json反序列化为 list型
BootstrapFileResult res = await UploadCommonAsync(); //图片上传并返回  图片id
var picid = res.ImgId;
PicandPoint user = new PicandPoint();
user.LevelId = dataPosition[0].id;
user.PositionX = dataPosition[0].positionX;
user.PositionY = dataPosition[0].positionY;
user.FotoId = picid;
JsonResult result = await CreatePoint(user);
return result;
}

[HttpPost]     ////将文件保存到指定路径，然后在存到数据库

public async Task<BootstrapFileResult> UploadCommonAsync()
{
////var data = Request.Form["data"];
var files = Request.Form.Files;
var baseDir = _options.ImgDir;
var res = new BootstrapFileResult();
var now = DateTime.Now;
if (!Directory.Exists(baseDir))
{
Directory.CreateDirectory(baseDir);
}
for (int i = 0; i < files.Count; ++i)
{
var newnamere = "";
var file = files[i];

var imgid = 0;
try
{
var orgName = file.FileName;
var newName = GetRandomFileName(orgName);
newnamere = newName;
imgid = await _indexer.StoreImageRecord(orgName, newnamere);

var filePath = baseDir + "/" + newName;
using (var stream = new FileStream(filePath, FileMode.Create))
{
await file.CopyToAsync(stream);  //将图片写到指定文件夹
}
var bitmap = new ImageSharp.Image(file.OpenReadStream());
var width = bitmap.Width;
var height = bitmap.Height;
await _indexer.UpdateImageDataEx(imgid, width, height);
}
catch (Exception e) { continue; }

res.ImgId = imgid;

}

return res;
}

///这个方法是将获取到的 data为stringvalue类型数据转化为list型：

private List<UpPoint> GetSortModel(string sortModel)
{ List<UpPoint> list = new List<UpPoint>();
if (sortModel == null)
{
return list;
}
string array = $"[{sortModel}]";
var deserialized = JsonConvert.DeserializeObject<List<UpPoint>>(array);
return deserialized;
}