问在HttpClient 6.0中发送json对象和IFormFile时，IFormFile返回不支持的媒体类型错误
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Stack Overflow用户

提问于 2022-08-22 23:06:45

回答 1查看 99关注 0票数 1

过去三天，我一直在努力将复杂类型的序列化json (称为fileItem的DTO对象)和名为文件的IFormFile类型发送到我的API中的一个，它接受两个输入，一个FileItem对象和IFormFile对象。

但是我一直收到一个错误“不支持的媒体类型”。请注意，当我只发送文件或仅将对象发送到API端点时，通过更新端点以只接受文件或只接受complexType，那么它可以正常工作，但如果同时发送这两个文件，则会得到“不支持的媒体类型”错误，该错误在我发送的请求中已经可用

请指导我正确的方向，你的帮助将是非常感谢的。

ASP.NET MVC web应用程序

public async Task<string> SaveFiles(FileItem _fileItem2, IFormFile _file)
{
    using (var multipartFormContent = new MultipartFormDataContent())
    {
        var fileItem = new StringContent(
        JsonSerializer.Serialize(_fileItem2), Encoding.UTF8, Application.Json);
        multipartFormContent.Add(fileItem, "fileItem");

        // Add the file
        var fileStreamContent = new StreamContent(_file.OpenReadStream());
        fileStreamContent.Headers.ContentType = MediaTypeHeaderValue.Parse(_file.ContentType);
        multipartFormContent.Add(fileStreamContent, name: "file", _file.FileName);

        // Method 1 : this method returns Unsupported media type, but if file is removed then it works fine.
        var response = await httpClient.PostAsync("/Upload/SaveFileWithData", multipartFormContent);

        // Method 2 : this method also returns Unsupported media type, but if file is removed then it works fine.
        var request = new HttpRequestMessage(HttpMethod.Post, "/Upload/SaveFileWithData");
        request.Content = multipartFormContent;
        var responsemsg = await httpClient.SendAsync(request);

        responsemsg.EnsureSuccessStatusCode();

        return await responsemsg.Content.ReadAsStringAsync();
    }
}

这是.NET 6.0WebAPI(上面我们发送给这个API的请求)。

[HttpPost()]
[Route("SaveFileWithData")]
public async Task<string> SaveFileWithData(FileItem? fileItem, IFormFile? file)
{
    int i = 2;
    return "fileSavedSuccessfully";
}

asp.net-core-webapi

httpclient

iformfile

回答 1

Stack Overflow用户

发布于 2022-08-23 19:44:56

下面是一个您可以遵循的完整的工作演示：

型号：

public class FileItem
{
    public string FileName { get; set; }
    public string Type { get; set; }
}

MVC：

[HttpPost]
public async Task<string> SaveFiles(FileItem _fileItem2, IFormFile _file)
{
    HttpClient httpClient = new HttpClient();
    httpClient.BaseAddress = new Uri("https://localhost:7241/");
    using (var multipartFormContent = new MultipartFormDataContent())
    {

        multipartFormContent.Add(new StringContent(_fileItem2.FileName), "FileName");
        multipartFormContent.Add(new StringContent(_fileItem2.Type), "Type");

        var fileStreamContent = new StreamContent(_file.OpenReadStream());
        
        multipartFormContent.Add(fileStreamContent, name: "file", _file.FileName);

        var response = await httpClient.PostAsync("/Upload/SaveFileWithData", multipartFormContent);

        //...
    }
}

网络APi：

[HttpPost()]
[Route("SaveFileWithData")]
public async Task<string> SaveFileWithData([FromForm]FileItem? fileItem, [FromForm] IFormFile? file)
{
    int i = 2;
    return "fileSavedSuccessfully";
}