Question

我从JSON文件创建了ListView。现在我想从被点击的ViewCell传递数据，这样我就可以继续我的流程了。

以下是这个函数listViewJson_ItemTapped最终应该在每个项目中执行的操作：

启动用户必须拍摄2张照片的相机
拍摄的照片将如下命名：$"{id}-{curDateTime}.jpg"
这两张图片将上传到web服务的目录中，其中也存储了上述JSON文件

现在我不知道如何从点击的ViewCell传递数据。此外，我坚持第二张强制照片。到目前为止，我的代码可以拍摄1张照片，但上传会抛出一个未处理的异常（现在从IIS端看到这个问题）。

这是来自ListView：

的XAML代码

<ListView x:Name="listViewJson" Grid.Column="0" BackgroundColor="White" ItemTapped="listViewJson_ItemTapped">
                    <ListView.ItemTemplate>
                        <DataTemplate>
                            <ViewCell>
                                <Grid HorizontalOptions="Center" VerticalOptions="Center">
                                    <Grid.ColumnDefinitions>
                                        <ColumnDefinition Width="Auto" />
                                        <ColumnDefinition Width="Auto" />
                                        <ColumnDefinition Width="Auto" />
                                    </Grid.ColumnDefinitions>
                                    <Grid.RowDefinitions>
                                        <RowDefinition Height="Auto" />
                                    </Grid.RowDefinitions>
                                    <Label Grid.Column="0" Text="{Binding id}" FontAttributes="Bold" />
                                    <Label Grid.Column="1" Text="{Binding fzg_kz}" FontAttributes="Bold" />
                                    <Label Grid.Column="2" Text="{Binding timestamp}" FontAttributes="Bold" />
                                </Grid>
                            </ViewCell>
                        </DataTemplate>
                    </ListView.ItemTemplate>
                </ListView>

这是listViewJson_ItemTapped中的C＃代码隐藏：

private async void listViewJson_ItemTapped(object sender, EventArgs e)
        {
            {
                await CrossMedia.Current.Initialize();

                if (!CrossMedia.Current.IsCameraAvailable || !CrossMedia.Current.IsTakePhotoSupported)
                {
                    await DisplayAlert("No Camera", ":( No camera available.", "OK");
                    return;
                }

                DateTime dt = DateTime.Now.AddHours(2);
                var format = "MM/dd/yyyy_hh:mm:ss";
                String curDateTime = dt.ToString(format);

                var _mediaFile = await CrossMedia.Current.TakePhotoAsync(new Plugin.Media.Abstractions.StoreCameraMediaOptions
                {
                    Directory = "Sample",
                    Name = $"{curDateTime}.jpg"
                });

                if (_mediaFile == null)
                    return;

                var image = new Image();
                image.Source = ImageSource.FromStream(() =>
                {
                    return _mediaFile.GetStream();

                });

                var content = new MultipartFormDataContent();
                content.Add(new StreamContent(_mediaFile.GetStream()), "\"file\"", $"\"{_mediaFile.Path}\"");
                var httpClient = new HttpClient();
                var uploadServiceBaseAddress = "http://xxx.xxx.xxx.xxx/files";
                var httpResponseMessage = await httpClient.PostAsync(uploadServiceBaseAddress, content);
            };
        }

这个问题确实让我头疼，因为没有这个我就无法继续工作。我是编程新手，所以我们非常感谢任何建议和参考。

先谢谢，保罗

Answer 1

因此，如果我理解正确，那么您应该获得唯一的文件名：

((ObjectType)(e.Item)).Id.ToString() + "-" + DateTime.Now.ToString();

不要忘记用你用来填充列表的对象交换ObjectType。

对于相机两次我建议只做一个简单的循环，如果你愿意的话，你确实可以使用一个简单的进度条。

到目前为止，该未处理的例外有任何进展吗？我想做的就是找到这样的错误，就是在输出调试中写json，将json复制到Postman中，然后发送它。比你得到一个比Unhandled更好的错误

我希望这很清楚，gl！

为id编辑一些额外的例子。

例如，你得到了以下JSON：

{
"name":"John",
"age":30
}

现在，如果它在列表中并且您单击了，则需要转换它。我们创建了Class Called Person并给出了这2个字段（名称和年龄）公共阶层人 { 私人字符串名称; private int age;

    public Person() {

    }

    public int Age
    {
        get { return age; }
        set { age = value; }
    }

    public string Name
    {
        get { return name; }
        set { name = value; }
    }
}

现在你可以使用我先给你的代码，只需用Object替换ObjectType。

((Person)(e.Item)).Id.ToString() + "-" + DateTime.Now.ToString();

我如何上传我的图片（请注意这是一个脏版本，这意味着它仍然需要清理一些我为测试原因而放置的脏代码，它还有调试窗口中的json仍然存在，所以使用它如果它不起作用，我使用的客户端类似Httpclient，我给了它一个基地址。如果有什么不清楚，请不要犹豫要求

public static bool InsertAllFotos(tTodo ttodo, List<Fotos> fotos, List<string> blob)
        {
            //var test2 = blob[0].blob_data.Bytes;
            List<tSyndFoto> tFotos = new List<tSyndFoto>();
            foreach(var foto in fotos)
            {
                tSyndFoto tFoto = new tSyndFoto();
                tFoto.id_synd_dossier = ttodo.id_gebouw;
                tFoto.omschrijving = foto.Omschrijving;
                tFoto.id_todo = ttodo.id_todo;
                tFotos.Add(tFoto);
            }

            JObject json = new JObject();

            json.Add("fotos", JsonConvert.SerializeObject(tFotos));

            //tBlob tmpBlob = new tBlob();
            //tmpBlob.blob_data = new Binary();
            //tmpBlob.blob_data.Bytes = new byte[0];
            // tmpBlob.blob_data.Bytes =  blob[0].blob_data.Bytes;
            //var lijst = new List<tBlob>();
            //lijst.Add(tmpBlob);
            json.Add("blobs", JsonConvert.SerializeObject(blob));
            //json.Add("blobs", null);
            //string test = json.ToString();

            //var jon2 = JsonConvert.DeserializeObject(blob[0].blob_data.Bytes.ToString());
            var test = json.ToString();
           test =  test.Replace("\"[", "[");
           test =  test.Replace("]\"", "]");
           // test = test.Replace("\\n", "");
            test = test.Replace("\\", "");

            Debug.WriteLine(test);
            var content = new StringContent(test, Encoding.UTF8, "application/json");


            var resp = client.PostAsync("InsertFotos", content);


            if (resp.Result.IsSuccessStatusCode)
            {

                var repStr = resp.Result.Content.ReadAsStringAsync();


                JObject jo = JObject.Parse(repStr.Result.ToString());
                return jo.SelectToken("InsertFotosResult", false).ToObject<bool>();



            }

            return false;
        }

这是我从中获得的JSON（blobs是我的图片，我删除了一些数据，因为它太大了：

    {
  "fotos": [{"id_synd_foto":"00000000-0000-0000-0000-000000000000","id_blob":null,"id_synd_dossier":"xxx","web_image":null,"uploaded":null,"omschrijving":null,"datum":null,"id_todo":"xx","id_synd_eigenaarsnet_melding":null,"id_eigenaar":null,"id_synd_kavel":null,"bijlage_melding":null}],
  "blobs": ["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"]
}

进一步使用itemtapped-event

1 个答案: