Phone number validation in Microsoft dynamics AX 2012

The below code is used to validate the Phone number.

public boolean validateField(FieldId _fieldIdToCheck)
{
    boolean ret;
    Str         phonePattern = @"[0-9]";
 
    System.Text.RegularExpressions.Match  myMatch;

    ret = super(_fieldIdToCheck);

    if (_fieldIdToCheck == fieldNum(PracticeDemo, PhoneMobile))
    {
        myMatch = System.Text.RegularExpressions.Regex::Match(this.PhoneMobile, phonePattern);
         
        if (strLen(this.PhoneMobile)<10 || strLen(this.PhoneMobile)>10)
        {
            ret = checkFailed(strFmt("%1 please enter 10 digit mobile number", this.PhoneMobile));
        }
         
        if (!myMatch.get_Success())
        {
            ret = checkFailed(strFmt("%1 is not an valid phone number", this.PhoneMobile));
}
    }

    return ret;
}