关于超过js的number类型最大值（9007199254740992），的解决办法

bug经过：点击修改无法展示信息（修改时调用queryOne,以id(long)为值，页面传过去的id=1480042498255640-00 ，在数据库中该id=148004249825564012，即错误的id）

根本原因：

js的number类型有个最大值（安全值）。即2的53次方，为9007199254740992。如果超过这个值，那么js会出现不精确的问题。这个值为16位。

 

using System;
using System.ComponentModel;
using System.Linq;
using Newtonsoft.Json;

namespace Holder.Framework.Common
{
/// <inheritdoc />
/// <summary>
/// 大数据json序列化重写
/// </summary>
public sealed class NumberConverter : JsonConverter
{
/// <summary>
/// 转换成字符串的类型
/// </summary>
private readonly NumberConverterShip _ship;

/// <summary>
/// 大数据json序列化重写实例化
/// </summary>
public NumberConverter()
{
_ship = (NumberConverterShip)0xFF;
}

/// <summary>
/// 大数据json序列化重写实例化
/// </summary>
/// <param name="ship">转换成字符串的类型</param>
public NumberConverter(NumberConverterShip ship)
{
_ship = ship;
}

/// <inheritdoc />
/// <summary>
/// 确定此实例是否可以转换指定的对象类型。
/// </summary>
/// <param name="objectType">对象的类型。</param>
/// <returns>如果此实例可以转换指定的对象类型，则为：<c>true</c>，否则为：<c>false</c></returns>
public override bool CanConvert(Type objectType)
{
var typecode = Type.GetTypeCode(objectType.Name.Equals("Nullable`1") ? objectType.GetGenericArguments().First() : objectType);
switch (typecode)
{
case TypeCode.Decimal:
return (_ship & NumberConverterShip.Decimal) == NumberConverterShip.Decimal;
case TypeCode.Double:
return (_ship & NumberConverterShip.Double) == NumberConverterShip.Double;
case TypeCode.Int64:
return (_ship & NumberConverterShip.Int64) == NumberConverterShip.Int64;
case TypeCode.UInt64:
return (_ship & NumberConverterShip.UInt64) == NumberConverterShip.UInt64;
case TypeCode.Single:
return (_ship & NumberConverterShip.Single) == NumberConverterShip.Single;
default: return false;
}
}

/// <inheritdoc />
/// <summary>
/// 读取对象的JSON表示。
/// </summary>
/// <param name="reader">从 <see cref="T:Newtonsoft.Json.JsonReader" /> 中读取。</param>
/// <param name="objectType">对象的类型。</param>
/// <param name="existingValue">正在读取的对象的现有值。</param>
/// <param name="serializer">调用的序列化器实例。</param>
/// <returns>对象值。</returns>
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
return AsType(reader.Value.ToString(), objectType);
}

/// <summary>
/// 字符串格式数据转其他类型数据
/// </summary>
/// <param name="input">输入的字符串</param>
/// <param name="destinationType">目标格式</param>
/// <returns>转换结果</returns>
public static object AsType(string input, Type destinationType)
{
try
{
var converter = TypeDescriptor.GetConverter(destinationType);
if (converter.CanConvertFrom(typeof(string)))
{
return converter.ConvertFrom(null, null, input);
}

converter = TypeDescriptor.GetConverter(typeof(string));
if (converter.CanConvertTo(destinationType))
{
return converter.ConvertTo(null, null, input, destinationType);
}
}
catch
{
return null;
}
return null;
}

/// <inheritdoc />
/// <summary>
/// 写入对象的JSON表示形式。
/// </summary>
/// <param name="writer">要写入的 <see cref="T:Newtonsoft.Json.JsonWriter" /> 。</param>
/// <param name="value">要写入对象值</param>
/// <param name="serializer">调用的序列化器实例。</param>
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
if (value == null)
{
writer.WriteNull();
}
else
{
var objectType = value.GetType();
var typeCode = Type.GetTypeCode(objectType.Name.Equals("Nullable`1") ? objectType.GetGenericArguments().First() : objectType);
switch (typeCode)
{
case TypeCode.Decimal:
writer.WriteValue(((decimal)value).ToString("f6"));
break;
case TypeCode.Double:
writer.WriteValue(((double)value).ToString("f4"));
break;
case TypeCode.Single:
writer.WriteValue(((float)value).ToString("f2"));
break;
default:
writer.WriteValue(value.ToString());
break;
}
}
}
}

/// <summary>
/// 转换成字符串的类型
/// </summary>
[Flags]
public enum NumberConverterShip
{
/// <summary>
/// 长整数
/// </summary>
Int64 = 1,

/// <summary>
/// 无符号长整数
/// </summary>
UInt64 = 2,

/// <summary>
/// 浮点数
/// </summary>
Single = 4,

/// <summary>
/// 双精度浮点数
/// </summary>
Double = 8,

/// <summary>
/// 大数字
/// </summary>
Decimal = 16
}
}