Regex expression to validate textbox.

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I am trying to use same technique on click of a button, but I am facing issues with year greater than current year, Can you please have a look, if I missed something?

C#

private static Regex exprNumber = new Regex("^(405|505)(?19[5-9][0-9]|[2-9][0-9]{3})[0-9]{6}$");

if (txtsfn.Text != "" && txtlrn.Text !="" && txtovrbn.Text != '' && txtovrts.Text != "" && txtfpfn.Text != "" && txtfpln.Text != "" && txtfpfn.Text.Length >= 2 && txtfpln.Text.Length >= 2 &&txtsfn.Text.Length == 13 && txtlrn.Text.Length == 13)
{
    // m.Groups[year].Value will contain the year upon success
    // and be empty if the match fails
    Match m = exprNumber.Match(txtsfn.Text);
    int testedYear = 0;
    int.TryParse(m.Groups[year].Value, out testedYear);
    int currentYear = DateTime.Now.Year;
    
    if (!m.Success || testedYear > currentYear)
    {
        txtsfn.Focus(); // Set focus to the control that should be 
    }
}

It works fine with validating.

Any help is appreciated.

Thanks.

Posted 16-Nov-15 16:47pm

Member 12076824

Updated 16-Nov-15 17:02pm

George Jonsson

v3

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Comments

Patrice T 16-Nov-15 23:06pm

You have already posted a question on the same regex.
http://www.codeproject.com/Questions/1055117/Regex-Expression-to-validate-textbox?arn=0
and got answers.
Can you add details on the problem.

[no name] 16-Nov-15 23:16pm

can you share more details on the your facing issue

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George Jonsson · Accepted Answer · 2015-11-16T17:20:00

First you can change the massive if-statement in the beginning as
txtsfn.Text != "" and txtsfn.Text.Length == 13 will be taken care of by the regex.

Then you have forgotten to actually add a group name to the regular expression.

C#

private static Regex exprNumber = new Regex("^(405|505)(?19[5-9][0-9]|[2-9][0-9]{3})[0-9]{6}$");

should be

C#

private static Regex exprNumber = new Regex("^(405|505)(?<year>(19[5-9][0-9]|[2-9][0-9]{3}))[0-9]{6}$");

This means that m.Groups[year].Value will always be empty and as you have no check on that you don't notice this.
As this actually is a design issue and not a run time issue, you could add a debug print out so you at least will see the problem when debugging.

C#

if (txtlrn.Text !="" && txtovrbn.Text != '' && txtovrts.Text != "" && txtfpfn.Text != "" && txtfpln.Text != "" && txtfpfn.Text.Length >= 2 && txtfpln.Text.Length >= 2 && txtlrn.Text.Length == 13)
{
    // m.Groups[year].Value will contain the year upon success
    // and be empty if the match fails
    Match m = exprNumber.Match(txtsfn.Text);
    int testedYear = 0;
    int.TryParse(m.Groups[year].Value, out testedYear);
    if (testedYear < 1950)
        Debug.WriteLine("The year is not correct: {0}", testedYear);

    int currentYear = DateTime.Now.Year;

    if (!m.Success || testedYear > currentYear)
    {
        txtsfn.Focus(); // Set focus to the control that should be
    }
}