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namespace System.ComponentModel.DataAnnotations {
using System;
using System.ComponentModel.DataAnnotations.Resources;
using System.Text.RegularExpressions;
[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter, AllowMultiple = false)]
public sealed class PhoneAttribute : DataTypeAttribute {
// see unit tests for examples
private static Regex _regex = CreateRegEx();
private const string _additionalPhoneNumberCharacters = "-.()";
public PhoneAttribute()
: base(DataType.PhoneNumber) {
// DevDiv 468241: set DefaultErrorMessage not ErrorMessage, allowing user to set
// ErrorMessageResourceType and ErrorMessageResourceName to use localized messages.
DefaultErrorMessage = DataAnnotationsResources.PhoneAttribute_Invalid;
}
public override bool IsValid(object value) {
if (value == null) {
return true;
}
string valueAsString = value as string;
// Use RegEx implementation if it has been created, otherwise use a non RegEx version.
if (_regex != null) {
return valueAsString != null && _regex.Match(valueAsString).Length > 0;
}
else {
if (valueAsString == null) {
return false;
}
valueAsString = valueAsString.Replace("+", string.Empty).TrimEnd();
valueAsString = RemoveExtension(valueAsString);
bool digitFound = false;
foreach (char c in valueAsString) {
if (Char.IsDigit(c)) {
digitFound = true;
break;
}
}
if (!digitFound) {
return false;
}
foreach (char c in valueAsString)
{
if (!(Char.IsDigit(c)
|| Char.IsWhiteSpace(c)
|| _additionalPhoneNumberCharacters.IndexOf(c) != -1)) {
return false;
}
}
return true;
}
}
private static Regex CreateRegEx() {
// We only need to create the RegEx if this switch is enabled.
if (AppSettings.DisableRegEx) {
return null;
}
const string pattern = @"^(\+\s?)?((?<!\+.*)\(\+?\d+([\s\-\.]?\d+)?\)|\d+)([\s\-\.]?(\(\d+([\s\-\.]?\d+)?\)|\d+))*(\s?(x|ext\.?)\s?\d+)?$";
const RegexOptions options = RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.ExplicitCapture;
// Set explicit regex match timeout, sufficient enough for phone parsing
// Unless the global REGEX_DEFAULT_MATCH_TIMEOUT is already set
TimeSpan matchTimeout = TimeSpan.FromSeconds(2);
try {
if (AppDomain.CurrentDomain.GetData("REGEX_DEFAULT_MATCH_TIMEOUT") == null) {
return new Regex(pattern, options, matchTimeout);
}
}
catch {
// Fallback on error
}
// Legacy fallback (without explicit match timeout)
return new Regex(pattern, options);
}
private static string RemoveExtension(string potentialPhoneNumber) {
int lastIndexOfExtension = potentialPhoneNumber
.LastIndexOf("ext.", StringComparison.InvariantCultureIgnoreCase);
if (lastIndexOfExtension >= 0) {
string extension = potentialPhoneNumber.Substring(lastIndexOfExtension + 4);
if (MatchesExtension(extension)) {
return potentialPhoneNumber.Substring(0, lastIndexOfExtension);
}
}
lastIndexOfExtension = potentialPhoneNumber
.LastIndexOf("ext", StringComparison.InvariantCultureIgnoreCase);
if (lastIndexOfExtension >= 0) {
string extension = potentialPhoneNumber.Substring(lastIndexOfExtension + 3);
if (MatchesExtension(extension)) {
return potentialPhoneNumber.Substring(0, lastIndexOfExtension);
}
}
lastIndexOfExtension = potentialPhoneNumber
.LastIndexOf("x", StringComparison.InvariantCultureIgnoreCase);
if (lastIndexOfExtension >= 0) {
string extension = potentialPhoneNumber.Substring(lastIndexOfExtension + 1);
if (MatchesExtension(extension)) {
return potentialPhoneNumber.Substring(0, lastIndexOfExtension);
}
}
return potentialPhoneNumber;
}
private static bool MatchesExtension(string potentialExtension) {
potentialExtension = potentialExtension.TrimStart();
if (potentialExtension.Length == 0) {
return false;
}
foreach (char c in potentialExtension) {
if (!Char.IsDigit(c)) {
return false;
}
}
return true;
}
}
}
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