Date problems when leaving blank.

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C#

string dateToformat = "dd/MM/yyyy";
DateTime dateTo = DateTime.ParseExact(tb_DateTo.Text, dateToformat, CultureInfo.InvariantCulture);

if (dateFrom == default(DateTime))
            {
                returnMessage += "Date From cannot be blank! <br />";
            }

There is an error, if I left blank my date from, it will have string was not a recognized datetime. I am not sure. Please help. Thanks.

Posted 31-Jan-14 4:37am

Member 10548723

Updated 31-Jan-14 4:39am

Bojjaiah

v2

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Bojjaiah · Answer 1 · 2014-01-31T04:49:00

When validating or working with datetimes always should be validate before converting.

C#

if (string.IsNullOrEmpty(tb_DateTo.Text.Trim()))
{
    returnMessage += "To Date cannot be blank!";
}

if (string.IsNullOrEmpty(dateFrom.Trim()))
{
    returnMessage += "Date From cannot be blank!"; 
}

//next steps

bowlturner · Answer 2 · 2014-01-31T04:44:00

Solution 1

Using string.IsNullOrEmpty will help check if there is any text. you can even use .Trim()

C#

DateTime dateFrom;

if (string.IsNullOrEmpty(tb_DateFrom.Text.Trim()))
{
    msg1 += "Date From cannot be blank! <br />";
}
else
{
    string dateFromformat = "dd/MM/yyyy";
    dateFrom = DateTime.ParseExact(tb_DateFrom.Text, dateFromformat, CultureInfo.InvariantCulture);
}

you can also use DateTime.TryParse(dateString, out convertDateTime);

Posted 31-Jan-14 4:44am

bowlturner

Updated 31-Jan-14 5:24am

v3

Comments

Member 10548723 31-Jan-14 10:46am

I declared my variable as a DateTime, this method is for string

bowlturner 31-Jan-14 10:49am

Well your code is off a little. 'dateFrom' is not declared anywhere in the code you posted. Give us the actual code and error and we can give better solutions.

Member 10548723 31-Jan-14 10:53am

Actually my dateFrom is inside this method to check if is empty

private string carinput(DateTime datefrom, DateTime dateTo)

{

if (dateFrom == default(DateTime))
{
returnMessage += "Date From cannot be blank! ";
}
if (dateTo == default(DateTime))
{
returnMessage += "Date To cannot be blank! ";
}

}

Is wrong?

bowlturner 31-Jan-14 10:59am

If someone is typing in a date, it starts as a string somewhere. You need to check if the string is null or empty before you try to convert it to a date. Then using DateTime.TryParse can try to parse the input string without throwing and error.

Member 10548723 31-Jan-14 11:05am

I try something like this

string dateFromformat = "dd/MM/yyyy";
DateTime dateFrom = DateTime.ParseExact(tb_DateFrom.Text, dateFromformat, CultureInfo.InvariantCulture);

if (String.IsNullOrEmpty(tb_DateFrom.Text))
{
msg1 += "Date From cannot be blank! ";
}

bowlturner 31-Jan-14 11:09am

you need to do the test for null or empty BEFORE you try to convert. I'll modify my answer

Member 10548723 31-Jan-14 11:24am

string dateToformat = "dd/MM/yyyy";
DateTime dateTo = DateTime.ParseExact("dd/MM/yyyy", dateToformat, CultureInfo.InvariantCulture);

if (String.IsNullOrEmpty(tb_eventDateTo.Text))
{
msg2 += "Date To cannot be blank! ";
}

else if (!DateTime.TryParseExact(tb_eventDateFrom.Text, "dd/MM/yyyy", CultureInfo.InvariantCulture, DateTimeStyles.None, out dateTo))
{
msg2 += "Date To must be a valid Date (dd/MM/yyyy)! ";
}

bowlturner 31-Jan-14 11:27am

you are on the right track but change the 2nd line to

DateTime dateTo;

Member 10548723 31-Jan-14 11:45am

Hmm I need it for my function. Do you know how to use javascript to check if the textbox is empty or the date is in the correct format?

bowlturner 31-Jan-14 11:54am

no, you don't. you are setting the dateTo value in the 'else if' statement. You need to do the check BEFORE you do the convert or you may get exceptions.