验证字符串是否是有效的电子邮件地址的最优雅的代码是什么?
当前回答
我认为最好的方法如下:
public static bool EmailIsValid(string email)
{
string expression = "\\w+([-+.']\\w+)*@\\w+([-.]\\w+)*\\.\\w+([-.]\\w+)*";
if (Regex.IsMatch(email, expression))
{
if (Regex.Replace(email, expression, string.Empty).Length == 0)
{
return true;
}
}
return false;
}
你可以在一个通用类中使用这个静态函数。
其他回答
来自@齿轮的投票最多的答案是最好的答案,但我已经尝试实现trim()字符串方法,因此它将从字符串开始到结束修剪所有用户空白。检查代码下面的完整示例-
bool IsValidEmail(string email)
{
try
{
email = email.Trim();
var addr = new System.Net.Mail.MailAddress(email);
return addr.Address == email;
}
catch
{
return false;
}
}
我发现这个正则表达式在检查@标记以外的东西和接受奇怪的边缘情况之间是一个很好的权衡:
^[^@\s]+@[^@\s]+(\.[^@\s]+)+$
它至少会让你在@标记周围放一些东西,并且至少放一个正常的域。
There are a lot of strong answers here. However, I recommend that we take a step back. @Cogwheel answers the question https://stackoverflow.com/a/1374644/388267. Nevertheless, it could be costly in a bulk validation scenario, if many of the email address being validated are invalid. I suggest that we employ a bit of logic before we enter into his try-catch block. I know that the following code could be written using RegEx but that could be costly for new developers to understand. This is my twopence worth:
public static bool IsEmail(this string input)
{
if (string.IsNullOrWhiteSpace(input)) return false;
// MUST CONTAIN ONE AND ONLY ONE @
var atCount = input.Count(c => c == '@');
if (atCount != 1) return false;
// MUST CONTAIN PERIOD
if (!input.Contains(".")) return false;
// @ MUST OCCUR BEFORE LAST PERIOD
var indexOfAt = input.IndexOf("@", StringComparison.Ordinal);
var lastIndexOfPeriod = input.LastIndexOf(".", StringComparison.Ordinal);
var atBeforeLastPeriod = lastIndexOfPeriod > indexOfAt;
if (!atBeforeLastPeriod) return false;
// CODE FROM COGWHEEL'S ANSWER: https://stackoverflow.com/a/1374644/388267
try
{
var addr = new System.Net.Mail.MailAddress(input);
return addr.Address == input;
}
catch
{
return false;
}
}
我只是想指出,最近在. net文档中增加了关于电子邮件验证的内容,也使用了Regex操作。 关于它们实现的详细解释可以在那里找到。
https://learn.microsoft.com/en-us/dotnet/standard/base-types/how-to-verify-that-strings-are-in-valid-email-format
为了方便起见,下面是他们的测试结果:
// Valid: david.jones@proseware.com
// Valid: d.j@server1.proseware.com
// Valid: jones@ms1.proseware.com
// Invalid: j.@server1.proseware.com
// Valid: j@proseware.com9
// Valid: js#internal@proseware.com
// Valid: j_9@[129.126.118.1]
// Invalid: j..s@proseware.com
// Invalid: js*@proseware.com
// Invalid: js@proseware..com
// Valid: js@proseware.com9
// Valid: j.s@server1.proseware.com
// Valid: "j\"s\""@proseware.com
// Valid: js@contoso.中国
基于@Cogwheel的回答,我想分享一个修改后的解决方案,适用于SSIS和“脚本组件”:
Place the "Script Component" into your Data Flow connect and then open it. In the section "Input Columns" set the field that contains the E-Mail Adresses to "ReadWrite" (in the example 'fieldName'). Switch back to the section "Script" and click on "Edit Script". Then you need to wait after the code opens. Place this code in the right method: public override void Input0_ProcessInputRow(Input0Buffer Row) { string email = Row.fieldName; try { System.Net.Mail.MailAddress addr = new System.Net.Mail.MailAddress(email); Row.fieldName= addr.Address.ToString(); } catch { Row.fieldName = "WRONGADDRESS"; } }
然后,您可以使用条件分割过滤掉所有无效记录或任何您想做的事情。
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