向接受 ICollection<IFormFile> 的 ASP.NET 控制器提交多个文件

Question

在我的 ASP.NET 核心后端中，我有一个如下所示的控制器函数：

[HttpPost]
[Route("documents/upload")]
public async Task<IActionResult> UploadFile(ICollection<IFormFile> files)
{
   ...
}

在我的前端，我这样调用函数：

var postSettings = {
    method: 'POST',
    credentials: 'include',
    mode: 'cors'
}
uploadDocuments( files ) {
    var data = new FormData();
    data.append('files', files);   
    postSettings.body = data;

    return fetch(endPoint + '/documents/upload', postSettings);
}

如果 "files" 是单个文件 - 不是包含一个文件的数组，而是单个文件对象 - UploadFile 将使用包含单个文件的 ICollection<IFormFile> 调用。

如果 "files" 是一个文件列表，一个 FileList 或一个 File 对象数组，则调用 UploadFile 时带有一个空的 ICollection<IFormFile>。

如何提交文件列表以使其能够被解析为 ICollection<IFormFile>？

Answer 1

引用Uploading multiple files at once - with Fetch

uploadDocuments(endPoint, files) {
    var postSettings = {
        method: 'POST',
        credentials: 'include',
        mode: 'cors'
    };
    var data = new FormData();
    if(files.length > 0) {
        for(var x = 0; x < files.length; x++) {
            // the name has to be 'files' so that .NET could properly bind it
            data.append('files', files.item(x));    
        }
    } 
    postSettings.body = data;

    return fetch(endPoint + '/documents/upload', postSettings);
}

引用Uploading small files with model binding

When uploading files using model binding and the IFormFile interface, the action method can accept either a single IFormFile or an IEnumerable<IFormFile> (or List<IFormFile>) representing several files. The following example loops through one or more uploaded files, saves them to the local file system, and returns the total number and size of files uploaded.

[HttpPost]
[Route("documents/upload")]
public async Task<IActionResult> Post(List<IFormFile> files)
{
    long size = files.Sum(f => f.Length);

    // full path to file in temp location
    var filePath = Path.GetTempFileName();

    foreach (var formFile in files)
    {
        if (formFile.Length > 0)
        {
            using (var stream = new FileStream(filePath, FileMode.Create))
            {
                await formFile.CopyToAsync(stream);
            }
        }
    }

    // process uploaded files
    // Don't rely on or trust the FileName property without validation.

    return Ok(new { count = files.Count, size, filePath});
}

向接受 ICollection<IFormFile> 的 ASP.NET 控制器提交多个文件

Submitting multiple files to ASP.NET controller accepting an ICollection<IFormFile>

c#

asp.net-core

asp.net-core-mvc

fetch-api

iformfile