String was not recognized as a valid DateTime duri

问题:

I get the following error when i try to convert to date time.

String was not recognized as a valid DateTime.

 cost.b_date = DateTime.Parse(c_date.Text) ;//c_date.Text = 12/28/2012

Then i try

    string date = string.Format("{0:yyyy-MM-dd}",c_date.Text);
    cost.b_date = DateTime.Parse(date) ;

but i get the same exception how to fix this problem.

回答1:

Using string.Format when the input is a string is pointless.

If you know the format of the string, you should use DateTime.ParseExact or DateTime.TryParseExact. For example, for the string you've got, you could use:

DateTime date = DateTime.ParseExact(text, "MM/dd/yyyy",
                                    CultureInfo.InvariantCulture);

You should consider:

• Is this user input? If so, use TryParseExact to detect user error more easily without an exception.
• Do you definitely know the exact format? If not, using DateTime.TryParse may be more appropriate.
• Do you definitely know the culture? If it's not the culture of the current thread, you should specify it explicitly.
• Do you have to get the value as text to start with? If you could use an alternative form of input which gives you the value as a DateTime to start with, that would be preferable.

回答2:

CultureInfo provider = CultureInfo.InvariantCulture;
DateTime result = DateTime.ParseExact(c_date.Text, "d", provider);

回答3:

Try using DateTime.ParseExact.

DateTime date = DateTime.ParseExact(c_date.Text, "yyyy/MM/dd", null);