How do I convert an ISO 8601 string to a Delphi TDate?

Question

I can convert a Delphi TDate to ISO 8601 format easily using this:

DateTimeToString(result, 'yyyy-mm-dd', myDate);

What's the idiomatic way to do the inverse conversion? StringToDateTime() doesn't seem to exist.

Obviously I can do it the "hard" way by manually parsing the string and encoding the result, but that seems a poor choice.

Answer 1

why re-invent the wheel?

XML uses ISO 8601 for date and date-time storage.

Delphi has had built-in support for that since Delphi 6 in the XSBuiltIns unit.

This answer explains how for DateTime, this is for Date only using the TXSDate class:

with TXSDate.Create() do
  try
    AsDate := Date; // convert from TDateTime
    DateString := NativeToXS; // convert to WideString
  finally
    Free;
  end;

with TXSDate.Create() do
  try
    XSToNative(DateString); // convert from WideString
    Date := AsDate; // convert to TDateTime
  finally
    Free;
  end;

Answer 2

From XE8 onwards, use ISO8601ToDate (and DateToISO8601) from dateutils.pas.

http://docwiki.embarcadero.com/Libraries/XE8/en/System.DateUtils.ISO8601ToDate