使用C＃使用图像文件发布表单数据

问题描述

我正在尝试发送包含数据和图像文件的发布请求。但是当我在下面发送我的代码时，出现错误。请在客户端查看下面的代码。

varCombo = {}
counter = 0
for i in infos:
    frame = Frame(principalFrame,bd=1)
    frame.grid(row=counter,column=0,pady=20)
    frame.columnconfigure(0,weight=1)

    label = Label(frame,text=i.name)
    label.grid(row=0,sticky="news")
    label.columnconfigure(0,weight=1)

    var1 = StringVar(window)
    var1.set(i.default)

    combo = ttk.Combobox(frame,state="readonly",textvariable=var1,values=i.values)
    combo.grid(row=1,sticky="news")
    combo.columnconfigure(0,weight=1)
    combo.rowconfigure(0,weight=1)
    varCombo[i.name] = var1

    counter = counter + 1

在WebAPI上，控制器显示在下面

    public async Task<HttpContent> PostRequestAsync(string requestUri)
    {
        string jsonString = string.Empty;
        StringContent stringJsonContent = default(StringContent);
        HttpResponseMessage requestResponse = new HttpResponseMessage();

        try
        {
            stringJsonContent = new StringContent(jsonString,Encoding.UTF8,"application/json");
            requestResponse = await this.httpClient.PostAsync(requestUri,stringJsonContent);

            if (requestResponse.IsSuccessStatusCode)
            {
                return requestResponse?.Content;
            }
            else if (requestResponse.StatusCode == HttpStatusCode.InternalServerError)
            {
            }
            else if (requestResponse.StatusCode == HttpStatusCode.Unauthorized)
            {
            }

        }
        catch (Exception ex)
        {
            throw ex.InnerException;
        }
        return requestResponse?.Content;
    }
}

模型是

    [HttpPost]     
    public async Task<ActionResult> UpdateProfile([FromForm] UpdateProfile updateProfile)

但是在POSTMAN中，我使用下面的命令成功上传了文件，因此我感觉客户端的代码有问题。任何人都可以建议我需要在代码上添加什么才能工作？我遇到错误，无法发送请求。

解决方法

在客户代码中，您不使用表单对象来传输数据。 StringContent存储表单的值而不是键。您可以使用MultipartFormDataContent对象来传输所有表单和文件。另外，我给出一个示例代码。

客户端中的代码。

class Program
{
    static async Task Main(string[] args)
    {
       await PostRequestAsync(@"D:\upload\1.jpg",new HttpClient(),"https://localhost:44370/api/UpdateProfile");
    }
    public static async Task<string> PostRequestAsync(string filePath,HttpClient _httpClient,string _url)
    {
        if (string.IsNullOrWhiteSpace(filePath))
        {
            throw new ArgumentNullException(nameof(filePath));
        }
        if (!File.Exists(filePath))
        {
            throw new FileNotFoundException($"File [{filePath}] not found.");
        }

        //Create form
        using var form = new MultipartFormDataContent();
        var bytefile = AuthGetFileData(filePath);
        var fileContent = new ByteArrayContent(bytefile);
        fileContent.Headers.ContentType = MediaTypeHeaderValue.Parse("multipart/form-data");
        form.Add(fileContent,"Image",Path.GetFileName(filePath));

        //the other data in form
        form.Add(new StringContent("Mr."),"firstName");
        form.Add(new StringContent("Loton"),"lastName");
        form.Add(new StringContent("Names--"),"Name");
        var response = await _httpClient.PostAsync($"{_url}",form);
        response.EnsureSuccessStatusCode();
        var responseContent = await response.Content.ReadAsStringAsync();

        return responseContent;
    }

    //Convert file to byte array
    public static byte[] AuthGetFileData(string fileUrl)
    {
        using (FileStream fs = new FileStream(fileUrl,FileMode.OpenOrCreate,FileAccess.ReadWrite))
        {
            byte[] buffur = new byte[fs.Length];
            using (BinaryWriter bw = new BinaryWriter(fs))
            {
                bw.Write(buffur);
                bw.Close();
            }
            return buffur;
        }
    }
}

WebApi中的操作

[ApiController]
[Route("[controller]")]
public class ApiController:Controller
{
    [HttpPost("get")]
    public string get([FromForm]UpdateProfile updateProfile)
    {
        return "get";
    }
    [HttpPost("UpdateProfile")]
    public async Task<ActionResult> UpdateProfile([FromForm] UpdateProfile updateProfile)
    {
        return Json("The result data "); 
    }
}

模型

public class UpdateProfile : BaseModel
{
    public string firstName { get; set; }
    public string lastName { get; set; }
    public IFormFile Image { get; set; }
}
public class BaseModel
{
    public string Name { get; set; }
}

结果：