c# - 将新数据附加到现有的 JSON 文件

Question

我到处寻找解决方案，并在过去几周尝试实现我自己的解决方案，但我就是想不出任何办法。

如果有任何帮助，我将不胜感激!

我有一个文件，看起来像 (file.json):

{
  "Expense": {
    "Name": "OneTel Mobile Bill",
    "Amount": "39.90",
    "Due": "28/12/2011",
    "Recurrence": "1 Months",
    "Paid": "0",
    "LastPaid": "01/01/2002"
  }
}

在我的应用程序中，当我创建一个新的“费用”时，我想将该新费用附加到这个现有的 JSON 文件中，所以它看起来像这样:

{
  "Expense": {
    "Name": "OneTel Mobile Bill",
    "Amount": "39.90",
    "Due": "28/12/2011",
    "Recurrence": "1 Months",
    "Paid": "0",
    "LastPaid": "01/01/2002"
  },
  "Expense": {
    "Name": "Loan Repayment",
    "Amount": "50.00",
    "Due": "08/03/2012",
    "Recurrence": "3 Months",
    "Paid": "0",
    "LastPaid": "08/12/2011"
  }
}

这就是我创建 JSON 并写入文件的方式:

async public void WriteToFile(string type, string data)
{
    file = await folder.GetFileAsync(file.FileName);
    IRandomAccessStream writestream = await file.OpenAsync(FileAccessMode.ReadWrite);


    IOutputStream outputstream = writestream.GetOutputStreamAt(0);
    DataWriter datawriter = new DataWriter(outputstream);
    datawriter.WriteString(data);

    await datawriter.StoreAsync();
    outputstream.FlushAsync().Start();
}

private void CreateExpenseButton_Click(object sender, RoutedEventArgs e)
{
    //Create the Json file and save it with WriteToFile();
    JObject jobject =
        new JObject(
            new JProperty("Expense",
                new JObject(
                    new JProperty("Name", NameTextBox.Text),
                    new JProperty("Amount", AmountTextBox.Text),
                    new JProperty("Due", DueTextBox.Text),
                    new JProperty("Recurrence", EveryTextBox.Text + " " + EveryComboBox.SelectionBoxItem),
                    new JProperty("Paid", "0"),
                    new JProperty("LastPaid", "Never")
                           )
                         )
                   );
    try
    {
        WriteToFile(Expenses, jobject.ToString());

        // Close the flyout now.
        this.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
    }
    catch (Exception exception)
    {
        Debug.Write(exception.Message);

    }
}

我正在使用 James Newton King 的 Json.NET 库，它非常棒，但即使在阅读了包含的文档之后，我仍然完全不知道如何读取 JSON 文件并将数据附加到它。

是否有任何示例可以演示这是如何完成的，或者您可以推荐另一个 C# 库来帮助我完成此操作？

编辑

这就是我从 json 文件中读取单笔费用的方式:

        JObject json = JObject.Parse(data);
        Expense expense = new Expense
        {
            Amount = (string)json["Expense"]["Amount"],
            Due = (string)json["Expense"]["Due"],
            Name = (string)json["Expense"]["Name"]
        };

        Debug.Write(expense.Amount);

Answer 1

您可以尝试将数据反序列化为对象 Expence 并添加您的数据，然后将对象(对象列表)序列化为文件。