Loss of accuracy when saving the DateTimeOffset parameter in the project settings

Question

When I save DateTimeOffest in my project settings, I lose some precision:

The first variable is the original value before serialization. The second is the value after Deserialization.

In fact, my variable is serialized like this in the configuration file:

 <?xml version="1.0" encoding="utf-8"?> <configuration> <userSettings> <MyApp.Properties.Settings> [...] <setting name="LatestCheckTimestamp" serializeAs="String"> <value>02/22/2013 14:39:06 +00:00</value> </setting> [...] </MyApp.Properties.Settings> </userSettings> </configuration> 

Can I specify some serialization options to improve accuracy?

I know I can use some workaround, for example by storing Ticks and offset values ​​or something like that, but I would like to know if there is a better way.

EDIT : More info: I'm using the standard Visual Studio project options to save my value:

 MyApp.Settings.Default.LatestCheckTimestamp = initialLatestCheckTimestamp; MyApp.Settings.Default.Save(); 

MyApp.Settings is a class generated by Visual Studio when editing settings on the project properties page.

EDIT 2: Solution :

Based on Matt Johnson's answer, this is what I did:

• Renamed parameter from LatestCheckTimestamp to LatestCheckTimestampString , but not in my code
• The following Wrapper has been added to an independent file to complete the partial Settings class:

.

 public DateTimeOffset LatestCheckTimestamp { get { return DateTimeOffset.Parse(LatestCheckTimestampString); } set { LatestCheckTimestampString = value.ToString("o"); } } 

The new configuration file now looks like this:

 <configuration> <userSettings> <MyApp.Properties.Settings> [...] <setting name="LatestCheckTimestampString" serializeAs="String"> <value>2013-02-22T16:54:04.3647473+00:00</value> </setting> </MyApp.Properties.Settings> </userSettings> </configuration> 

... and my code is still

 MyApp.Settings.Default.LatestCheckTimestamp = initialLatestCheckTimestamp; MyApp.Settings.Default.Save(); 

Answer 1

The most reliable way to serialize DateTimeOffset is the RoundTrip pattern , which is specified in the standard serialization string "o" .

It uses the ISO8601 standard, which is very compatible with other systems, languages, frameworks, etc. Your value will look like this: 2013-02-22T14:39:06.0000000+00:00 .

.Net will store fractional seconds up to 7 decimal places in this format.

If you can show some code of how you store and retrieve the settings of your application, I can show you where to specify the format string. In most cases, just .ToString("o") .