尝试将 ImageData 发送到我的数据库

Question

我正在尝试将图像数据发送到我的数据库，但我不确定应该如何让它工作。这是我当前的代码：

这是我的数据库 csfile，我尝试在其中为我的数据库创建图像（它正在工作，但我不确定是否应该将它作为字节 [] 发送，因为我的数据库需要它作为文件）

static public async Task<bool> createInfo (byte[] thePicture) // should I send it as byte??

我 "create" 将数据发送到我的数据库 csfile 的页面。

myViewModel = new PhotoAlbumViewModel ();

async void button (object sender, EventArgs args)
    { 
        var createResult = await parseAPI.createInfo 
            (myViewModel.ImageData); //sending my imagedata to my database
    }

还有我的 PhotoAlbumViewModel，我在其中创建了包含图像数据字节的图像数据：

    private byte[] imageData;

    public byte[] ImageData { get { return imageData; } }

    private byte[] ReadStream(Stream input)
    {
        byte[] buffer = new byte[16*1024];
        using (MemoryStream ms = new MemoryStream())
        {
            int read;
            while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
            {
                ms.Write(buffer, 0, read);
            }
            return ms.ToArray();
        }
    }

public async Task SelectPicture()
    {
        Setup ();

        ImageSource = null;


        try
        {
            var mediaFile = await _Mediapicker.SelectPhotoAsync(new CameraMediaStorageOptions
                {
                    DefaultCamera = CameraDevice.Front,
                    MaxPixelDimension = 400
                });

            VideoInfo = mediaFile.Path;
            ImageSource = ImageSource.FromStream(() => mediaFile.Source);

            imageData = ReadStream(mediaFile.Source);


        }
        catch (System.Exception ex)
        {
            Status = ex.Message;
        }
    }

已更新数据库 cscode：

static public async Task<bool> createInfo (byte[] thePicture)

    {
        var httpClientRequest = new HttpClient ();

        httpClientRequest.DefaultRequestHeaders.Add ("X-Parse-Application-Id", appId);
        httpClientRequest.DefaultRequestHeaders.Add ("X-Parse-REST-API-Key", apiKey);

        var postData = new Dictionary <object, object> ();
        postData.Add ("image", thePicture);

        var jsonRequest = JsonConvert.SerializeObject(postData);

        jsonRequest = jsonRequest.Replace ("\"ACLDATA\"", "{\""+userId+"\" : { \"read\": true, \"write\": true }, \"*\" : {}}");

        HttpContent content = new StringContent(jsonRequest, System.Text.Encoding.UTF8, "application/json");

        var result = await httpClientRequest.PostAsync("https://api.parse.com/1/classes/Info", content);
        var resultString = await result.Content.ReadAsStringAsync ();

        return  true;
    }

Answer 1

最后，您遇到的问题是您对 Post API 的调用是错误的。

它需要一个内容为二进制内容的纯 POST 请求，而您正在执行一个 REST 请求。

这段代码可以做到：

    public static void SendFile(string FileName, string MimeType, byte[] FileContent, string ClientId, string ApplicationId, string ApiKey, Action<string> OnCompleted)
    { 
        string BaseServer =   "https://api.parse.com/{0}/files/{1}";

        HttpWebRequest req = HttpWebRequest.CreateHttp(string.Format(BaseServer, ClientId, FileName));

        SetHeader(req, "X-Parse-Application-Id", ApplicationId);
        SetHeader(req, "X-Parse-REST-API-Key", ApiKey);

        req.Method = "POST";
        req.ContentType = MimeType;

        req.BeginGetRequestStream((iResult) =>
            {
                var str = req.EndGetRequestStream(iResult);
                str.Write(FileContent, 0, FileContent.Length);

                req.BeginGetResponse((iiResult) => {

                    var resp = req.EndGetResponse(iiResult);

                    string result = "";

                    using (var sr = new StreamReader(resp.GetResponseStream()))
                        result = sr.ReadToEnd();

                    OnCompleted(result);

                }, null);


            }, null);

    }

    //Modified from 
    public static void SetHeader(HttpWebRequest Request, string Header, string Value) {
        // Retrieve the property through reflection.
        PropertyInfo PropertyInfo = Request.GetType().GetRuntimeProperty(Header.Replace("-", string.Empty));
        // Check if the property is available.
        if (PropertyInfo != null) {
            // Set the value of the header.
            PropertyInfo.SetValue(Request, Value, null);
        } else {
            // Set the value of the header.
            Request.Headers[Header] = Value;
        }
    }

那么你可以这样称呼它：

SendFile("image.jpg", "image/jpg", theByteArray, theClientId, yourAppId, yourApiKey, (result) => {

          //do whatever you want with the result from the server

});

注意我没有实现任何异常处理，您应该在 GetResponseStream 周围添加一个 try-catch 以防服务器给出带有错误代码的响应并从生成的 WebException 中获取响应。

尝试将 ImageData 发送到我的数据库

Trying to send an ImageData to my database

c#

image

xamarin

xamarin.forms