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Getting Mime DateTime in .NET
I'm working a parser that's parsing and updating some raw Email headers and I realized while working on this that my mail component was not properly setting the mail headers when sending email. This code predates .NET 2.0 so I had originally created a custom component.
Sounds easy enough, but dates in email messages need to be Mime encoded. I figured there must be something in .NET that converts Time strings to Mime and GTM values, but after experimenting around with various time formats I couldn't find anything.
In the end I just created my own since I couldn't dig anything up in a pinch:
///
/// Converts the passed date time value to Mime formatted time string
///
///
public static string MimeDateTime(DateTime Time)
{
TimeSpan Offset = TimeZone.CurrentTimeZone.GetUtcOffset(Time);
string sOffset = null;
if (Offset.Hours < 0)
sOffset = "-" + (Offset.Hours * -1).ToString().PadLeft(2, '0');
else
sOffset = "+" + Offset.Hours.ToString().PadLeft(2, '0');
sOffset += Offset.Minutes.ToString().PadLeft(2, '0');
return "Date: " + DateTime.Now.ToString("ddd, dd MMM yyyy hh:mm:ss",
System.Globalization.CultureInfo.InvariantCulture) +
" " + sOffset;
}
Interesting thing happened while I was screwing around with this: I thought it would be much easier to use Utc time and assign a 0000 time offset. So the following actually works as well:
string Time = DateTime.UtcNow.ToString("ddd, dd MMM yyyy HH:mm:ss",
System.Globalization.CultureInfo.InvariantCulture) + " +0000";
but this relies on the mail client fixing up the date time for sure and doesn't give any idea about the client's timezone. So I think the lengthier version is the right way to get the time to return.
BTW, to get GMT format time you can use this code just fine:
string Time = DateTime.UtcNow.ToString("ddd, dd MMM yyyy HH:mm:ss",
System.Globalization.CultureInfo.InvariantCulture) + " GMT";
I'm sure I'm missing some built-in way to do this, but here it is just in case
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The Voices of Reason
# re: Getting Mime DateTime in .NET
MessageBox.Show(dt.ToString("r"));
# re: Getting Mime DateTime in .NET
ToString("r") returns GMT time, but not the date offset based MIME time.
# re: Getting Mime DateTime in .NET
It is true ToString("r") returns "GMT", and not offset hours.
But it is still valid MIME - see rfc 822 :)
# re: Getting Mime DateTime in .NET
DateTime.Now.ToString("ddd, dd MMM yyyy HH:mm:ss zzz", CultureInfo.InvariantCulture).Remove(29, 1);
# re: Getting Mime DateTime in .NET
I've got the reverse problem - to parse string into DateTime. But maybe this example with format strings could be usefull in your case:
*/
DateTime str2dt(sd)
{
// something like string sd = "19 Oct 2005 16:20:47 +0400";
DateTime dt0 = null;
try
{
IFormatProvider culture = new CultureInfo("en-US", true);
string[] fmt = {"f", "F", "g", "G", "dd MMM yyyy HH:mm:ss zzz", "ddd, dd MMM yyyy HH:mm:ss G\\MT zzz"};
Console.WriteLine(DateTime.UtcNow.ToString(fmt[5], culture));
Console.WriteLine(sd);
dt0 = DateTime.ParseExact(sd, fmt, culture, DateTimeStyles.None);
foreach(string fmtstr in fmt)
Console.WriteLine(dt0.ToString(fmtstr));
}
catch
{
}
return dt0;
}