在 XAMARIN C# 中使用 FILE 发送 POST 请求

在网上看，我看到了一点如何发布“文件”，因此，我以这种方式编写了代码：

        var upfilebytes = File.ReadAllBytes((string)fPath);

        //create new HttpClient and MultipartFormDataContent and add our file, and StudentId
        HttpClient client = new HttpClient();

        MultipartFormDataContent content = new MultipartFormDataContent();
        ByteArrayContent baContent = new ByteArrayContent(upfilebytes);
        content.Add(baContent, "img", fPath);

        StringContent emailText = new StringContent(lbl_email.Text);
        content.Add(emailText, "email");

        string url = "http://192.168.178.77/TestLoginURL/api/updateUserImage.php";
        //upload MultipartFormDataContent content async and store response in response var
        var response =
            await client.PostAsync(url, content);
        //read response result as a string async into json var
        var responsestr = response.Content.ReadAsStringAsync().Result;

现在问题又来了……这是我的 API 代码：

<?php
$response = array();

if($_SERVER['REQUEST_METHOD']=='POST'){

    //getting values
    $img = $_FILES['img']['name'];
    $email = $_POST['email'];

    //including the db operation file
    require_once '../includes/DbOperation.php';

    $db = new DbOperation();

    $target = "/Applications/XAMPP/xamppfiles/htdocs/TestLoginURL/images/".basename($img);

    //inserting values
    if($db->updateImage((String)basename($img),$email)){
        $response['error']=false;
        $response['message']='Image added successfully - test fileName = '.(String)basename($img);
    }else{
        $response['error']=true;
        $response['message']='Could not add image';
    }
    if(move_uploaded_file($_FILES['img']['tmp_name'], $target)) {
        /*$response['error']=false;
        $response = "Image uploaded successfully";*/
    }else{
        $response['error']=true;
        $response = "Failed to upload image";
    }
}else{
    $response['error']=true;
    $response['message']='You are not authorized';
}
echo json_encode($response);

使用 Postman 它完美地工作，更新数据库中图像的名称并将图像物理插入到指定路径中，响应消息例如是这样的：{"error": false, "message": "Image added successfully - test文件名 = trollolollo.png"}

Now, the app saves the file in the right repository but does NOT UPDATE the name of the 'image' in the database ... BUT strangely, the "response" message in the debugger also correctly shows the name of the FILE ... So I just don't understand where I'm wrong ... Could someone help me with the code please? Thanks

OFF_TOPIC: usually, when I have to send only strings, I send a post request written in this way

            string url = "http://192.168.178.77/TestLoginURL/api/insertUser.php";

            FormUrlEncodedContent formContent = new FormUrlEncodedContent(new[]
            {
              new KeyValuePair<string, string>("nickname", nickname),
              new KeyValuePair<string, string>("password", password1),
              new KeyValuePair<string, string>("email", email)
            });

            var httpClient = new HttpClient();
            httpClient.DefaultRequestHeaders.Add("Accept", "application/json");
            try
            {
                CancellationTokenSource cts = new CancellationTokenSource();
                var responseMessage = httpClient.PostAsync(url, formContent).Result;
            }
            catch (Exception ex)
            {
                ex.Message.ToString();
                throw;
            }

but now, being a file and having no experience about it I am having difficulties... thanks again, I hope someone can help me with the code