Question

我有一个字符串，它可以获取如下所示的任何可能的值（请注意，其中两个值可以与下面的message1，message4相同，但是请记住，它可以使用相同或不同的大小写，但是我想忽略大小写并从列表中进行比较，我得到了这个。）

string Message = "No need of validation";
string Message = "No need of validation for certain members only"
string Message = "Validation for this member - No need of validation"
string Message = "no need of validation";

Message.IndexOf("No need of validation", StringComparison.CurrentCultureIgnoreCase) >= 0)

现在我上面的代码将在2、3种情况下返回true / false？

我希望仅对1,4为true，对2,3为false。请确认一下如果这不正确，请帮我修改代码

Answer 1

如果按原样运行，则所有4个都是正确的。

        string Message = "No need of validation";
        Console.WriteLine("1 : {0}", Message.IndexOf("No need of validation", StringComparison.CurrentCultureIgnoreCase));
        Message = "No need of validation for certain members only";
        Console.WriteLine("2 : {0}", Message.IndexOf("No need of validation", StringComparison.CurrentCultureIgnoreCase));
        Message = "Validation for this member - No need of validation";
        Console.WriteLine("3 : {0}", Message.IndexOf("No need of validation", StringComparison.CurrentCultureIgnoreCase));
        Message = "no need of validation";
        Console.WriteLine("4 : {0}", Message.IndexOf("No need of validation", StringComparison.CurrentCultureIgnoreCase));

这是因为忽略大小写的比较字符串在每个消息字符串中都存在，因此索引将始终为0或更高。

如果不管大小写如何都比较字符串是否相等，则应该使用字符串Compare：

        Message = "No need of validation";
        Console.WriteLine("1 : {0}", string.Compare(Message,"No need of validation", true));
        Message = "No need of validation for certain members only";
        Console.WriteLine("2 : {0}", string.Compare(Message, "No need of validation", true));
        Message = "Validation for this member - No need of validation";
        Console.WriteLine("3 : {0}", string.Compare(Message, "No need of validation", true));
        Message = "no need of validation";
        Console.WriteLine("4 : {0}", string.Compare(Message, "No need of validation", true));

哪个会给您想要的结果。

Answer 2

如果我正确理解了结果，则可以使用旧的string.Compare，它自.Net 1.1起就出现了

Compare(String, String, CultureInfo, CompareOptions)

使用指定的规则比较两个指定的String对象，并且返回一个整数，指示它们在排序中的相对位置订单。

返回

Int32一个32位带符号整数，指示词法关系   在strA和strB之间，如下表所示

值条件


按排序顺序，strA小于零strA之前。

按排序顺序，零strA出现在与strB相同的位置。

大于strA的strA大于零。

示例

string Message1 = "No need of validation";
string Message2 = "No need of validation for certain members only";
string Message3 = "Validation for this member - No need of validation";
string Message4 = "no need of validation";
Console.WriteLine(string.Compare("No need of validation", Message1, StringComparison.InvariantCultureIgnoreCase));
Console.WriteLine(string.Compare("No need of validation", Message2, StringComparison.InvariantCultureIgnoreCase));
Console.WriteLine(string.Compare("No need of validation", Message3, StringComparison.InvariantCultureIgnoreCase));
Console.WriteLine(string.Compare("No need of validation", Message4, StringComparison.InvariantCultureIgnoreCase));

输出

0
-1
-1
0

比较带有整个字符串的indexof的字符串值

2 个答案: