This repository has been archived by the owner on Jan 23, 2023. It is now read-only.
/
CreditCardAttribute.cs
58 lines (50 loc) · 1.81 KB
/
CreditCardAttribute.cs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
namespace System.ComponentModel.DataAnnotations
{
[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter,
AllowMultiple = false)]
public sealed class CreditCardAttribute : DataTypeAttribute
{
public CreditCardAttribute()
: base(DataType.CreditCard)
{
// Set DefaultErrorMessage, allowing user to set
// ErrorMessageResourceType and ErrorMessageResourceName to use localized messages.
DefaultErrorMessage = SR.CreditCardAttribute_Invalid;
}
public override bool IsValid(object value)
{
if (value == null)
{
return true;
}
if (!(value is string ccValue))
{
return false;
}
ccValue = ccValue.Replace("-", string.Empty);
ccValue = ccValue.Replace(" ", string.Empty);
var checksum = 0;
var evenDigit = false;
// Note: string.Reverse() does not exist for WinPhone
for (var i = ccValue.Length - 1; i >= 0; i--)
{
var digit = ccValue[i];
if (digit < '0' || digit > '9')
{
return false;
}
var digitValue = (digit - '0') * (evenDigit ? 2 : 1);
evenDigit = !evenDigit;
while (digitValue > 0)
{
checksum += digitValue % 10;
digitValue /= 10;
}
}
return (checksum % 10) == 0;
}
}
}