String was not recognized as a valid datetime.

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I am coding an validation for birthdate where the date must be 18 years old. I use for birthdate was a textbox with a date method.

I tried this code but the error was String was not recognized as a valid DateTime.

What I have tried:

txtBirthdate.Attributes["max"] = DateTime.Now.ToString("yyyy-MM-dd");

        DateTime BirthDate = DateTime.Parse(txtBirthdate.Text);
        DateTime CurrentDate = DateTime.Today;
        int Age = CurrentDate.Year - BirthDate.Year;
        if (Age < 18)
        {
            lbbday.Text = "Invalid Birth Day";
        }

Posted 7-Nov-17 15:45pm

Edgar Bots

Updated 7-Nov-17 16:33pm

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san2debug 7-Nov-17 22:11pm

can you confirm whether your getting error from first line or others

Graeme_Grant 7-Nov-17 22:43pm

It sounds like an invalid [DateTime] character was entered. TryParse will fix that - see solution 2 below. However, you have another problem, see solution 3 below.

3 solutions

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Karthik_Mahalingam · Answer 1 · 2017-11-07T16:22:00

Solution 2

use DateTime.TryParseExact Method [^]

DateTime BirthDate;
          if (DateTime.TryParseExact("yyyy-MM-dd", txtBirthdate.Text.Trim(), System.Globalization.CultureInfo.CurrentCulture, System.Globalization.DateTimeStyles.None, out BirthDate))
          {
              DateTime CurrentDate = DateTime.Today;
              int Age = CurrentDate.Year - BirthDate.Year;
              if (Age < 18)
              {
                  lbbday.Text = "Invalid Birth Day";
              }
          }
          else {
              lbbday.Text = "Please enter a valid date (yyyy-MM-dd)";
          }

Posted 7-Nov-17 16:22pm

Karthik_Mahalingam

Comments

Graeme_Grant 7-Nov-17 22:36pm

That is what I first thought but is not the problem ... Step-through debugging explains why... Have another closer look... then look at my solution. ;)

Edgar Bots 7-Nov-17 22:41pm

I tried putting the codes and i tried putting the birthdate a today date but when i click add it accepted it. The validation won't work. i don't know how. please help thanks

Karthik_Mahalingam 7-Nov-17 22:48pm

what is the value you are getting in txtBirthdate.Text.Trim() ?

Graeme_Grant · Answer 2 · 2017-11-07T16:33:00

Your code works as designed. Have you tried debugging[^]? Set a breakpoint on the first line and step through your code and watch the values:

txtBirthdate.Attributes["max"] = "2017-11-08"
BirthDate = {8/11/2017 12:00:00 AM}
CurrentDate = {8/11/2017 12:00:00 AM}
Age = 0

Now do you see, using debugging, what is actually happening in your code?

ashwani bakshi · Answer 3 · 2017-11-07T16:08:00

Hi Edgar Bots
You should remove "YYY-MM-DD" from ToString.It will work
Example

textBox1.Text = DateTime.Now.ToString();
            DateTime BirthDate = DateTime.Parse(textBox1.Text);
            DateTime CurrentDate = DateTime.Today;
            int Age = CurrentDate.Year - BirthDate.Year;
                if (Age < 18)
                {
                    textBox2.Text = "Invalid Birth Day";
                }

The code is working by removing that from tostring().

String was not recognized as a valid datetime.

3 solutions

Solution 2

Solution 3

Solution 1

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