c#-4.0 - JavaScriptSerializer从日期减去一天

Question

我正在使用JavaScriptSerializer序列化DateTime，但是当我反序列化它时，它显示比序列化日期少一天的时间:

这是测试:

  DateTime startDate=new DateTime(2012,1,20);//set the 20th of January
  JavaScriptSerializer  serializer=new JavaScriptSerializer();
  string serializeDate= serializer.Serialize(startDate);
  DateTime afterDeserialize= serializer.Deserialize<DateTime>(serializeDate);//I get 19th of Jan
  Assert.Equals(startDate, afterDeserialize);

首先，我是因为javascript datetime格式而启用它，但是正如我所知道的javascript，Month是零索引 0=January，但是我得到的日期比原始日期少一天。

Answer 1

它不会任意损失一天，它会转换为UTC日期(或者我应该说使用UTC日期格式的日期)，因此当它不序列化时，您将不再属于自己的时区。它基本上在执行:

DateTime whateverDate = /* incoming date */;
long ticks = whateverDate.ToUniversalTime() // make UTC
  .Subtract(new DateTime(1970, 1, 1))       // subtract UNIX Epoch
  .TotalMilliseconds();                     // get milliseconds since then
// push in to the "\/Date(ticks)\/" format
String value = String.Format(@"\/Date({0})\/", ticks);

但是，请尝试以下操作:

// or you rely on it serializing, then bring it back to your own local time
// (apply the time zone).
afterDeserialize = afterDeserialize.ToLocalTime();

现在，您可以将UTC时间恢复为本地时间(已应用时区)。

通过测试:

DateTime startDate              = new DateTime(2012,1,20);
JavaScriptSerializer serializer = new JavaScriptSerializer();
String serializeDate            = serializer.Serialize(startDate);
DateTime afterDeserialize       = serializer.Deserialize<DateTime>(serializeDate)
                                  .ToLocalTime(); // Note: this is added

Assert.Equals(startDate, afterDeserialize); // pass!