c# - 验证 ABN(澳大利亚商业编号)

Question

我需要一些现代 C# 代码来检查澳大利亚商业号码 (ABN) 是否有效。

松散的要求是

• ABN 已由用户输入
• 允许在任何位置使用空格以使数字可读
• 如果包含除数字和空格之外的任何其他字符 - 即使包含合法的数字序列，验证也应该失败
• 此检查是调用 ABN search webservice 的前奏这将节省输入明显错误的电话

验证数字的确切规则在 abr.business.gov.au 中指定。为了简洁和清楚起见，此处省略。规则不会随时间改变。

Answer 1

这是基于Nick Harris's示例，但经过清理以使用现代 C# 习语

/// <summary>
/// http://stackoverflow.com/questions/38781377
/// 1. Subtract 1 from the first (left) digit to give a new eleven digit number         
/// 2. Multiply each of the digits in this new number by its weighting factor         
/// 3. Sum the resulting 11 products         
/// 4. Divide the total by 89, noting the remainder         
/// 5. If the remainder is zero the number is valid          
/// </summary>
public bool IsValidAbn(string abn)
{
    abn = abn?.Replace(" ", ""); // strip spaces

    int[] weight = { 10, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19 };
    int weightedSum = 0;

    //0. ABN must be 11 digits long
    if (string.IsNullOrEmpty(abn) || !Regex.IsMatch(abn, @"^\d{11}$"))
    {
        return false;
    }

    //Rules: 1,2,3                                  
    for (int i = 0; i < weight.Length; i++)
    {
        weightedSum += (int.Parse(abn[i].ToString()) - (i == 0 ? 1 : 0)) * weight[i];
    }

    //Rules: 4,5                 
    return weightedSum % 89 == 0;
}

额外的 xUnit 测试让您的技术主管开心...

[Theory]
[InlineData("33 102 417 032", true)]
[InlineData("29002589460", true)]
[InlineData("33 102 417 032asdfsf", false)]
[InlineData("444", false)]
[InlineData(null, false)]
public void IsValidAbn(string abn, bool expectedValidity)
{
    var sut = GetSystemUnderTest();
    Assert.True(sut.IsValidAbn(abn) == expectedValidity);
}