JsonConvert.PopulateObject()未正确处理十进制类型数据 [英] JsonConvert.PopulateObject() is not handling the decimal type data properly

问题描述

我有一个JSON字符串:

I have a JSON string:

{"PaymentVoucherNumber":15,"PaymentVoucherDate":"2019-09-10T00:00:00","pvExpiryDate":"2019-09-22T00:00:00","Amount":35.000,"ReceiptNumber":0}

在此json中，Amount是一个双精度值.

In this json the Amount is a double value.

public partial class VoucherList 
{
    [JsonProperty("PaymentVoucherNumber")]
    public long PaymentVoucherNumber { get; set; }

    [JsonProperty("PaymentVoucherDate")]
    public string PaymentVoucherDate { get; set; }

    [JsonProperty("pvExpiryDate")]
    public string PvExpiryDate { get; set; }

    [JsonProperty("Amount")]
    public double Amount { get; set; }

    [JsonProperty("ReceiptNumber")]
    public long ReceiptNumber { get; set; }
}

我使用了JsonConvert.PopulateObject().但是结果是，金额字段将以小数部分删除.即仅35

I have used JsonConvert.PopulateObject(). But in the result, the amount field is coming as decimal part removed.ie just 35

VoucherList pv=new VoucherList();
JsonConvert.PopulateObject(json,pv);

请咨询...

推荐答案

您的问题是，在您的数据模型中，对于Amount，您使用的是double而不是decimal:

Your problem is that, in your data model, you are using double and not decimal for Amount:

[JsonProperty("Amount")]
public double Amount { get; set; }

您需要将其更改为decimal:

[JsonProperty("Amount")]
public decimal Amount { get; set; }

当您这样做时，JSON中的小数位数将被保存在decimal结构中.这是可能的，因为如 docs :

When you do, the number of decimal digits in the JSON will be remembered in the decimal struct. This is possible because, as explained in the docs:

十进制数是一个浮点值，它由一个符号，一个数值(其中值中的每个数字都介于0到9之间)和一个比例因子(表示将整数分隔开的浮点小数的位置)组成数值的小数部分. ...

A decimal number is a floating-point value that consists of a sign, a numeric value where each digit in the value ranges from 0 to 9, and a scaling factor that indicates the position of a floating decimal point that separates the integral and fractional parts of the numeric value. ...

比例因子还保留十进制数中的所有尾随零.尾随零不会影响算术或比较操作中小数的值.但是，如果应用了适当的格式字符串，则ToString方法可能会显示尾随零.

The scaling factor also preserves any trailing zeros in a Decimal number. Trailing zeros do not affect the value of a Decimal number in arithmetic or comparison operations. However, trailing zeros might be revealed by the ToString method if an appropriate format string is applied.

对于 double 是纯IEEE 754二进制浮点表示形式，因此不能区分35，35.0或35.0000.结果，当您在填充后检查pv.Amount时，将显示35作为35.0 JSON值.

No such capability is present for double which is a purely IEEE 754 binary floating-point representation and thus cannot distinguish between 35, 35.0 or 35.0000. As a result, when you inspect pv.Amount after population, 35 is shown for the 35.0 JSON value.

示例小提琴.

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