VarToDateTime(VarDateFromStr)使用哪种日期格式? [英] Which date format does VarToDateTime(VarDateFromStr) use?

问题描述

我最近在日期转换方面一直遇到问题.我的应用程序在某些工作站上运行，无法将字符串正确转换为日期.

I've been having problems lately with date conversion lately. Some workstations my application run on don't convert string to date correctly.

我将问题归结为VarDateFromStr，该问题似乎并没有检查LOCALE_SSHORTDATE进行转换.我想知道是否有人知道它对转换进行DID检查.还是不同的行为仅链接到不同的DLL版本?

I tracked the issue down to VarDateFromStr that doesn't seem to be checking LOCALE_SSHORTDATE to make the conversion. I was wondering if anyone knew what it DID check for the conversion. Or does the different behavior only linked to different DLL version?

GetLocaleStr(GetThreadLocale, LOCALE_SSHORTDATE, 'm/d/yy'); // returns 'dd-MM-yyyy'
FormatDateTime('dd-MM-yyyy', VarToDateTime('05-11-2010')); //returns '11-05-2010'

有人告诉我，将(控制面板中的)短日期格式从"dd-MM-yyyy"更改为"任何"，然后再更改为"dd-MM-yyyy"，即可解决此问题.不过，我仍然必须对此进行验证.

I've been told that changing the short date format (in the control panel) from 'dd-MM-yyyy' to whatever and back to 'dd-MM-yyyy' fixed the problem. I still have to verify this though.

Kindda忘了提，该问题仅在WinXP SP3上得到确认.

Kindda forgot to mention, the problem has only been confirmed on WinXP SP3 yet.

推荐答案

肯， VarToDateTime 函数在内部调用 VarDateFromStr 函数，该函数使用 VAR_LOCALE_USER_DEFAULT 常量来格式化日期.

Ken, the VarToDateTime function internally calls the VarDateFromStr function wich uses the VAR_LOCALE_USER_DEFAULT constant to format the date.

要确定其中包含VAR_LOCALE_USER_DEFAULT的格式，您可以使用此代码

to determine wich format contains the VAR_LOCALE_USER_DEFAULT you can use this code

var
 FormatSettings      : TFormatSettings;
begin
      GetLocaleFormatSettings(VAR_LOCALE_USER_DEFAULT, formatSettings);
      ShowMessage('VarToDateTime is using this format to convert dates  '+formatSettings.ShortDateFormat);
end;

现在为避免出现问题，您可以使用StrToDateTime函数将变量值转换为字符串，然后转换为日期时间

now to avoid your problem you can convert your variant value to string and then to datetime using the StrToDateTime function

var
v                   : variant;
FormatSettings      : TFormatSettings;
Begin
      v:='05-11-2010';//this is your variant.
      FormatSettings.ShortDateFormat:='dd-mm-yyyy';//use this format in the conversion
      ShowMessage(FormatDateTime('dd-MM-yyyy', StrToDateTime(V,FormatSettings)));
end;

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