How to compare dates independent of current culture in .NET

I hardcode a trial expiration date in my .net 2.5 app. how do I compare it with the user's system date such that the comparison is accurate regardless of the user's culture settings?

DateTime maxTrialDate = DateTime.Parse("11/17/2020", new System.Globalization.CultureInfo("en-US"));

DateTime curDate = DateTime.Parse(DateTime.Now.ToShortDateString(), new System.Globaliz开发者_高级运维ation.CultureInfo("en-US"));

//the next line of code uses the DateDiff method to compare the two dates -dont recall its //exact syntax.

On my XP machine the above works if the control panel regional setting for datetime is en-US, but if I change it to en-AU, then the above code that sets curDate fires a FormatException "Date is not in a correct string format"

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If you avoid using strings to represent the dates, you will not encounter this problem:

DateTime maxTrialDate = new DateTime(2020, 11, 17);

if (DateTime.Now.Date > maxTrialDate)
{
     // expired
}

The DateTime is created by explicitly defining the day, month and year components, so the regional settings will not confuse matters.

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What about just using CultureInfo.InvariantCulture all over the place?

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You can use System.Globalization.CultureInfo.InvariantCulture

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If I remember correctly, in most places outside the US, the standard date format is dd/mm/yyyy, rather than the US standard of mm/dd/yyyy. It might be that when trying to parse the date, it believes the 17 is the month, which is an invalid month, thus causing the error.

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Why are you using the Parse method if you are hardcoding expiration date just compare it to DateTime.now

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The FormatException is expected since you explicitly ask the parser to use en-US.

Try calling the one-argument overload of DateTime.Parse(), or alternatively, if you really want to use the two-args overload (*cough*FxCop*cough*), something like:

using System.Globalization;

DateTime.Parse("11/17/2020", CultureInfo.CurrentCulture);