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

我写了一个函数来检查电子邮件是否有效。在大多数情况下,这似乎对我很有效。

结果:

dasddas-@.com => FALSE
-asd@das.com => FALSE
as3d@dac.coas- => FALSE
dsq!a?@das.com => FALSE
_dasd@sd.com => FALSE
dad@sds => FALSE
asd-@asd.com => FALSE
dasd_-@jdas.com => FALSE
asd@dasd@asd.cm => FALSE
da23@das..com => FALSE
_dasd_das_@9.com => FALSE

d23d@da9.co9 => TRUE
dasd.dadas@dasd.com => TRUE
dda_das@das-dasd.com => TRUE
dasd-dasd@das.com.das => TRUE

代码:

    private bool IsValidEmail(string email)
    {
        bool valid = false;
        try
        {
            var addr = new System.Net.Mail.MailAddress(email);
            valid = true;
        }
        catch
        {
            valid = false;
            goto End_Func;
        }

        valid = false;
        int pos_at = email.IndexOf('@');
        char checker = Convert.ToChar(email.Substring(pos_at + 1, 1));
        var chars = "qwertyuiopasdfghjklzxcvbnm0123456789";
        foreach (char chr in chars)
        {
            if (checker == chr)
            {
                valid = true;
                break;
            }
        }
        if (valid == false)
        {
            goto End_Func;
        } 

        int pos_dot = email.IndexOf('.', pos_at + 1);
        if(pos_dot == -1)
        {
            valid = false;
            goto End_Func;
        }

        valid = false;
        try
        {
            checker = Convert.ToChar(email.Substring(pos_dot + 1, 1));
            foreach (char chr in chars)
            {
                if (checker == chr)
                {
                    valid = true;
                    break;
                }
            }
        }
        catch
        {
            valid = false;
            goto End_Func;
        }

        Regex valid_checker = new Regex(@"^[a-zA-Z0-9_@.-]*$");
        valid = valid_checker.IsMatch(email);
        if (valid == false)
        {
            goto End_Func;
        }

        List<int> pos_list = new List<int> { };
        int pos = 0;
        while (email.IndexOf('_', pos) != -1)
        {
            pos_list.Add(email.IndexOf('_', pos));
            pos = email.IndexOf('_', pos) + 1;
        }

        pos = 0;
        while (email.IndexOf('.', pos) != -1)
        {
            pos_list.Add(email.IndexOf('.', pos));
            pos = email.IndexOf('.', pos) + 1;
        }

        pos = 0;
        while (email.IndexOf('-', pos) != -1)
        {
            pos_list.Add(email.IndexOf('-', pos));
            pos = email.IndexOf('-', pos) + 1;
        }

        int sp_cnt = pos_list.Count();
        pos_list.Sort();
        for (int i = 0; i < sp_cnt - 1; i++)
        {
            if (pos_list[i] + 1 == pos_list[i + 1])
            {
                valid = false;
                break;
            }

            if (pos_list[i]+1 == pos_at || pos_list[i]+1 == pos_dot)
            {
                valid = false;
                break;
            }
        }

        if(valid == false)
        {
            goto End_Func;
        }

        if (pos_list[sp_cnt - 1] == email.Length - 1 || pos_list[0] == 0)
        {
            valid = false;
        }

    End_Func:;
        return valid;
    }

其他回答

最优雅的方法是使用. net的内置方法。

这些方法:

都是经过考验的。我在自己的专业项目中使用了这些方法。 内部使用正则表达式,这是可靠和快速的。 由微软为c#编写。没有必要做重复的工作。 返回bool类型的结果。True表示邮件有效。

适用于。net 4.5及以上版本的用户

将此引用添加到项目中:

System.ComponentModel.DataAnnotations

现在你可以使用下面的代码:

(new EmailAddressAttribute().IsValid("youremailhere@test.test"));

使用实例

下面是一些需要声明的方法:

protected List<string> GetRecipients() // Gets recipients from TextBox named `TxtRecipients`
{
    List<string> MethodResult = null;

    try
    {
        List<string> Recipients = TxtRecipients.Text.Replace(",",";").Replace(" ", "").Split(';').ToList();

        List<string> RecipientsCleaned = new List<string>();

        foreach (string Recipient in RecipientsCleaned)
        {
            if (!String.IsNullOrWhiteSpace(Recipient))
            {
                RecipientsNoBlanks.Add(Recipient);

            }

        }

        MethodResult = RecipientsNoBlanks;

    }
    catch//(Exception ex)
    {
        //ex.HandleException();
    }

    return MethodResult;

}


public static bool IsValidEmailAddresses(List<string> recipients)
{
    List<string> InvalidAddresses = GetInvalidEmailAddresses(recipients);

    return InvalidAddresses != null && InvalidAddresses.Count == 0;

}

public static List<string> GetInvalidEmailAddresses(List<string> recipients)
{
    List<string> MethodResult = null;

    try
    {
        List<string> InvalidEmailAddresses = new List<string>();

        foreach (string Recipient in recipients)
        {
            if (!(new EmailAddressAttribute().IsValid(Recipient)) && !InvalidEmailAddresses.Contains(Recipient))
            {
                InvalidEmailAddresses.Add(Recipient);

            }

        }

        MethodResult = InvalidEmailAddresses;

    }
    catch//(Exception ex)
    {
        //ex.HandleException();

    }

    return MethodResult;

}

...以及演示它们的代码:

List<string> Recipients = GetRecipients();

bool IsValidEmailAddresses = IsValidEmailAddresses(Recipients);

if (IsValidEmailAddresses)
{
    //Emails are valid. Your code here

}
else
{
    StringBuilder sb = new StringBuilder();

    sb.Append("The following addresses are invalid:");

    List<string> InvalidEmails = GetInvalidEmailAddresses(Recipients);

    foreach (string InvalidEmail in InvalidEmails)
    {
        sb.Append("\n" + InvalidEmail);

    }

    MessageBox.Show(sb.ToString());

}

另外,这个例子:

扩展超出规范,因为一个字符串用于包含0,一个或多个由分号分隔的电子邮件地址; 清楚地演示了如何使用EmailAddressAttribute对象的IsValid方法。

对于.Net 4.5以下版本的用户,可以选择

对于.Net 4.5不可用的情况,我使用以下解决方案:

具体来说,我使用:

public static bool IsValidEmailAddress(string emailAddress)
{
    bool MethodResult = false;

    try
    {
        MailAddress m = new MailAddress(emailAddress);

        MethodResult = m.Address == emailAddress;

    }
    catch //(Exception ex)
    {
        //ex.HandleException();

    }

    return MethodResult;

}

public static List<string> GetInvalidEmailAddresses(List<string> recipients)
{
    List<string> MethodResult = null;

    try
    {
        List<string> InvalidEmailAddresses = new List<string>();

        foreach (string Recipient in recipients)
        {
            if (!IsValidEmail(Recipient) && !InvalidEmailAddresses.Contains(Recipient))
            {
                InvalidEmailAddresses.Add(Recipient);

            }

        }

        MethodResult = InvalidEmailAddresses;

    }
    catch //(Exception ex)
    {
        //ex.HandleException();

    }

    return MethodResult;

}

我根据维基百科的规则和样本地址创建了一个电子邮件地址验证程序。对于那些不介意多看一点代码的人,这里。说实话,我不知道电子邮件地址规范中有这么多疯狂的规则。我没有完全验证主机名或ipaddress,但它仍然通过了维基百科上的所有测试用例。

using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace EmailValidateUnitTests
{
    [TestClass]
    public class EmailValidationUnitTests
    {
        [TestMethod]
        public void TestEmailValidate()
        {
            // Positive Assertions
            Assert.IsTrue("prettyandsimple@example.com".IsValidEmailAddress());
            Assert.IsTrue("very.common@example.com".IsValidEmailAddress());
            Assert.IsTrue("disposable.style.email.with+symbol@example.com".IsValidEmailAddress());
            Assert.IsTrue("other.email-with-dash@example.com".IsValidEmailAddress());
            Assert.IsTrue("\"much.more unusual\"@example.com".IsValidEmailAddress());
            Assert.IsTrue("\"very.unusual.@.unusual.com\"@example.com".IsValidEmailAddress()); //"very.unusual.@.unusual.com"@example.com
            Assert.IsTrue("\"very.(),:;<>[]\\\".VERY.\\\"very@\\\\ \\\"very\\\".unusual\"@strange.example.com".IsValidEmailAddress()); //"very.(),:;<>[]\".VERY.\"very@\\ \"very\".unusual"@strange.example.com
            Assert.IsTrue("admin@mailserver1".IsValidEmailAddress());
            Assert.IsTrue("#!$%&'*+-/=?^_`{}|~@example.org".IsValidEmailAddress());
            Assert.IsTrue("\"()<>[]:,;@\\\\\\\"!#$%&'*+-/=?^_`{}| ~.a\"@example.org".IsValidEmailAddress()); //"()<>[]:,;@\\\"!#$%&'*+-/=?^_`{}| ~.a"@example.org
            Assert.IsTrue("\" \"@example.org".IsValidEmailAddress()); //" "@example.org (space between the quotes)
            Assert.IsTrue("example@localhost".IsValidEmailAddress());
            Assert.IsTrue("example@s.solutions".IsValidEmailAddress());
            Assert.IsTrue("user@com".IsValidEmailAddress());
            Assert.IsTrue("user@localserver".IsValidEmailAddress());
            Assert.IsTrue("user@[IPv6:2001:db8::1]".IsValidEmailAddress());
            Assert.IsTrue("user@[192.168.2.1]".IsValidEmailAddress());
            Assert.IsTrue("(comment and stuff)joe@gmail.com".IsValidEmailAddress());
            Assert.IsTrue("joe(comment and stuff)@gmail.com".IsValidEmailAddress());
            Assert.IsTrue("joe@(comment and stuff)gmail.com".IsValidEmailAddress());
            Assert.IsTrue("joe@gmail.com(comment and stuff)".IsValidEmailAddress());

            // Failure Assertions
            Assert.IsFalse("joe(fail me)smith@gmail.com".IsValidEmailAddress());
            Assert.IsFalse("joesmith@gma(fail me)il.com".IsValidEmailAddress());
            Assert.IsFalse("joe@gmail.com(comment and stuff".IsValidEmailAddress());
            Assert.IsFalse("Abc.example.com".IsValidEmailAddress());
            Assert.IsFalse("A@b@c@example.com".IsValidEmailAddress());
            Assert.IsFalse("a\"b(c)d,e:f;g<h>i[j\\k]l@example.com".IsValidEmailAddress()); //a"b(c)d,e:f;g<h>i[j\k]l@example.com
            Assert.IsFalse("just\"not\"right@example.com".IsValidEmailAddress()); //just"not"right@example.com
            Assert.IsFalse("this is\"not\\allowed@example.com".IsValidEmailAddress()); //this is"not\allowed@example.com
            Assert.IsFalse("this\\ still\\\"not\\\\allowed@example.com".IsValidEmailAddress());//this\ still\"not\\allowed@example.com
            Assert.IsFalse("john..doe@example.com".IsValidEmailAddress());
            Assert.IsFalse("john.doe@example..com".IsValidEmailAddress());
            Assert.IsFalse(" joe@gmail.com".IsValidEmailAddress());
            Assert.IsFalse("joe@gmail.com ".IsValidEmailAddress());
        }
    }

    public static class ExtensionMethods
    {
        private const string ValidLocalPartChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!#$%&'*+-/=?^_`{|}~";
        private const string ValidQuotedLocalPartChars = "(),:;<>@[]. ";
        private const string ValidDomainPartChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-:";

        private enum EmailParseMode
        {
            BeginLocal, Local, QuotedLocalEscape, QuotedLocal, QuotedLocalEnd, LocalSplit, LocalComment,
            At,
            Domain, DomainSplit, DomainComment, BracketedDomain, BracketedDomainEnd
        };

        public static bool IsValidEmailAddress(this string s)
        {
            bool valid = true;

            bool hasLocal = false, hasDomain = false;
            int commentStart = -1, commentEnd = -1;
            var mode = EmailParseMode.BeginLocal;
            for (int i = 0; i < s.Length; i++)
            {
                char c = s[i];
                if (mode == EmailParseMode.BeginLocal || mode == EmailParseMode.LocalSplit)
                {
                    if (c == '(') { mode = EmailParseMode.LocalComment; commentStart = i; commentEnd = -1; }
                    else if (c == '"') { mode = EmailParseMode.QuotedLocal; }
                    else if (ValidLocalPartChars.IndexOf(c) >= 0) { mode = EmailParseMode.Local; hasLocal = true; }
                    else { valid = false; break; }
                }
                else if (mode == EmailParseMode.LocalComment)
                {
                    if (c == ')')
                    {
                        mode = EmailParseMode.Local; commentEnd = i;
                        // comments can only be at beginning and end of parts...
                        if (commentStart != 0 && ((commentEnd + 1) < s.Length) && s[commentEnd + 1] != '@') { valid = false; break; }
                    }
                }
                else if (mode == EmailParseMode.Local)
                {
                    if (c == '.') mode = EmailParseMode.LocalSplit;
                    else if (c == '@') mode = EmailParseMode.At;
                    else if (c == '(') { mode = EmailParseMode.LocalComment; commentStart = i; commentEnd = -1; }
                    else if (ValidLocalPartChars.IndexOf(c) >= 0) { hasLocal = true; }
                    else { valid = false; break; }
                }
                else if (mode == EmailParseMode.QuotedLocal)
                {
                    if (c == '"') { mode = EmailParseMode.QuotedLocalEnd; }
                    else if (c == '\\') { mode = EmailParseMode.QuotedLocalEscape; }
                    else if (ValidLocalPartChars.IndexOf(c) >= 0 || ValidQuotedLocalPartChars.IndexOf(c) >= 0) { hasLocal = true; }
                    else { valid = false; break; }
                }
                else if (mode == EmailParseMode.QuotedLocalEscape)
                {
                    if (c == '"' || c == '\\') { mode = EmailParseMode.QuotedLocal; hasLocal = true; }
                    else { valid = false; break; }
                }
                else if (mode == EmailParseMode.QuotedLocalEnd)
                {
                    if (c == '.') { mode = EmailParseMode.LocalSplit; }
                    else if (c == '@') mode = EmailParseMode.At;
                    else if (c == '(') { mode = EmailParseMode.LocalComment; commentStart = i; commentEnd = -1; }
                    else { valid = false; break; }
                }
                else if (mode == EmailParseMode.At)
                {
                    if (c == '[') { mode = EmailParseMode.BracketedDomain; }
                    else if (c == '(') { mode = EmailParseMode.DomainComment; commentStart = i; commentEnd = -1; }
                    else if (ValidDomainPartChars.IndexOf(c) >= 0) { mode = EmailParseMode.Domain; hasDomain = true; }
                    else { valid = false; break; }
                }
                else if (mode == EmailParseMode.DomainComment)
                {
                    if (c == ')')
                    {
                        mode = EmailParseMode.Domain;
                        commentEnd = i;
                        // comments can only be at beginning and end of parts...
                        if ((commentEnd + 1) != s.Length && (commentStart > 0) && s[commentStart - 1] != '@') { valid = false; break; }
                    }
                }
                else if (mode == EmailParseMode.DomainSplit)
                {
                    if (ValidDomainPartChars.IndexOf(c) >= 0) { mode = EmailParseMode.Domain; hasDomain = true; }
                    else { valid = false; break; }
                }
                else if (mode == EmailParseMode.Domain)
                {
                    if (c == '(') { mode = EmailParseMode.DomainComment; commentStart = i; commentEnd = -1; }
                    else if (c == '.') { mode = EmailParseMode.DomainSplit; }
                    else if (ValidDomainPartChars.IndexOf(c) >= 0) { hasDomain = true; }
                    else { valid = false; break; }
                }
                else if (mode == EmailParseMode.BracketedDomain)
                {
                    if (c == ']') { mode = EmailParseMode.BracketedDomainEnd; }
                    else if (c == '.' || ValidDomainPartChars.IndexOf(c) >= 0) { hasDomain = true; }
                    else { valid = false; break; }
                }
                else if (mode == EmailParseMode.BracketedDomain)
                {
                    if (c == '(') { mode = EmailParseMode.DomainComment; commentStart = i; commentEnd = -1; }
                    else { valid = false; break; }
                }
            }
            bool unfinishedComment = (commentEnd == -1 && commentStart >= 0);

            return hasLocal && hasDomain && valid && !unfinishedComment;
        }
    }
}

正如在许多回答中提到的,电子邮件地址的领域是复杂的。在这种情况下,我强烈反对使用正则表达式。那些匹配(大多数)用例的异常复杂,难以读取,因此也难以维护。此外,它们仍然难以支持所有病例,而且速度缓慢。

微软的EmailAddress类在这方面有所帮助,但我认为也不是完美的。在几年前的一个开源项目中,我尝试使用定制的EmailParser。

在[EmailAddress]https://github.com/Qowaiv/Qowaiv/blob/master/src/Qowaiv/EmailAddress.cs中使用。

通过使用这种方法,不仅可以验证电子邮件地址,还可以清除显示名称的多种格式,去掉mailto:-前缀,并根据ip地址规范化域字面量,并将所有内容小写(注意,本地部分是大小写敏感的)。

你的解决方案应该支持的场景(上面提到的就是):

[TestCase(null)]
[TestCase("")]
[TestCase("..@test.com")]
[TestCase(".a@test.com")]
[TestCase("ab@sd@dd")]
[TestCase(".@s.dd")]
[TestCase("ab@988.120.150.10")]
[TestCase("ab@120.256.256.120")]
[TestCase("ab@120.25.1111.120")]
[TestCase("ab@[188.120.150.10")]
[TestCase("ab@188.120.150.10]")]
[TestCase("ab@[188.120.150.10].com")]
[TestCase("a@b.-de.cc")]
[TestCase("a@bde-.cc")]
[TestCase("a@bde.c-c")]
[TestCase("a@bde.cc.")]
[TestCase("ab@b+de.cc")]
[TestCase("a..b@bde.cc")]
[TestCase("_@bde.cc,")]
[TestCase("plainaddress")]
[TestCase("plain.address")]
[TestCase("@%^%#$@#$@#.com")]
[TestCase("@domain.com")]
[TestCase("Joe Smith &lt;email@domain.com&gt;")]
[TestCase("email.domain.com")]
[TestCase("email@domain@domain.com")]
[TestCase(".email@domain.com")]
[TestCase("email.@domain.com")]
[TestCase("email..email@domain.com")]
[TestCase("email@-domain.com")]
[TestCase("email@domain-.com")]
[TestCase("email@domain.com-")]
[TestCase("email@.domain.com")]
[TestCase("email@domain.com.")]
[TestCase("email@domain..com")]
[TestCase("email@111.222.333")]
[TestCase("email@111.222.333.256")]
[TestCase("email@[123.123.123.123")]
[TestCase("email@[123.123.123].123")]
[TestCase("email@123.123.123.123]")]
[TestCase("email@123.123.[123.123]")]
[TestCase("email@{leftbracket.com")]
[TestCase("email@rightbracket}.com")]
[TestCase("email@p|pe.com")]
[TestCase("isis@100%.nl")]
[TestCase("email@dollar$.com")]
[TestCase("email@r&amp;d.com")]
[TestCase("email@#hash.com")]
[TestCase("email@wave~tilde.com")]
[TestCase("email@exclamation!mark.com")]
[TestCase("email@question?mark.com")]
[TestCase("email@obelix*asterisk.com")]
[TestCase("email@grave`accent.com")]
[TestCase("email@colon:colon.com")]
[TestCase("email@caret^xor.com")]
[TestCase("email@=qowaiv.com")]
[TestCase("email@plus+.com")]
[TestCase("email@domain.com>")]
[TestCase("email( (nested) )@plus.com")]
[TestCase("email)mirror(@plus.com")]
[TestCase("email@plus.com (not closed comment")]
[TestCase("email(with @ in comment)plus.com")]
[TestCase(@"""Joe Smith email@domain.com")]
[TestCase(@"""Joe Smith' email@domain.com")]
[TestCase(@"""Joe Smith""email@domain.com")]
[TestCase("email@mailto:domain.com")]
[TestCase("mailto:mailto:email@domain.com")]
[TestCase("Display Name <email@plus.com> (after name with display)")]
[TestCase("ReDoSaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")]
public void IsInvalid(string email)
{
    Assert.IsFalse(EmailAddress.IsValid(email), email);
}

[TestCase("w@com")]
[TestCase("w.b.f@test.com")]
[TestCase("w.b.f@test.museum")]
[TestCase("a.a@test.com")]
[TestCase("ab@288.120.150.10.com")]
[TestCase("ab@188.120.150.10")]
[TestCase("ab@1.0.0.10")]
[TestCase("ab@120.25.254.120")]
[TestCase("ab@01.120.150.1")]
[TestCase("ab@88.120.150.021")]
[TestCase("ab@88.120.150.01")]
[TestCase("ab@[120.254.254.120]")]
[TestCase("local@2001:0db8:85a3:0000:0000:8a2e:0370:7334")]
[TestCase("local@[2001:0db8:85a3:0000:0000:8a2e:0370:7334]")]
[TestCase("2@bde.cc")]
[TestCase("-@bde.cc")]
[TestCase("a2@bde.cc")]
[TestCase("a-b@bde.cc")]
[TestCase("ab@b-de.cc")]
[TestCase("a+b@bde.cc")]
[TestCase("f.f.f@bde.cc")]
[TestCase("ab_c@bde.cc")]
[TestCase("_-_@bde.cc")]
[TestCase("k.haak@12move.nl")]
[TestCase("K.HAAK@12MOVE.NL")]
[TestCase("email@domain.com")]
[TestCase("email@domain")]
[TestCase("あいうえお@domain.com")]
[TestCase("local@あいうえお.com")]
[TestCase("firstname.lastname@domain.com")]
[TestCase("email@subdomain.domain.com")]
[TestCase("firstname+lastname@domain.com")]
[TestCase("email@123.123.123.123")]
[TestCase("email@[123.123.123.123]")]
[TestCase("1234567890@domain.com")]
[TestCase("a@domain.com")]
[TestCase("a.b.c.d@domain.com")]
[TestCase("aap.123.noot.mies@domain.com")]
[TestCase("1@domain.com")]
[TestCase("email@domain-one.com")]
[TestCase("_______@domain.com")]
[TestCase("email@domain.topleveldomain")]
[TestCase("email@domain.co.jp")]
[TestCase("firstname-lastname@domain.com")]
[TestCase("firstname-lastname@d.com")]
[TestCase("FIRSTNAME-LASTNAME@d--n.com")]
[TestCase("first-name-last-name@d-a-n.com")]
[TestCase("{local{name{{with{@leftbracket.com")]
[TestCase("}local}name}}with{@rightbracket.com")]
[TestCase("|local||name|with|@pipe.com")]
[TestCase("%local%%name%with%@percentage.com")]
[TestCase("$local$$name$with$@dollar.com")]
[TestCase("&local&&name&with&$@amp.com")]
[TestCase("#local##name#with#@hash.com")]
[TestCase("~local~~name~with~@tilde.com")]
[TestCase("!local!!name!with!@exclamation.com")]
[TestCase("?local??name?with?@question.com")]
[TestCase("*local**name*with*@asterisk.com")]
[TestCase("`local``name`with`@grave-accent.com")]
[TestCase("^local^^name^with^@xor.com")]
[TestCase("=local==name=with=@equality.com")]
[TestCase("+local++name+with+@equality.com")]
[TestCase("Joe Smith <email@domain.com>")]
[TestCase("email@domain.com (joe Smith)")]
[TestCase(@"""Joe Smith"" email@domain.com")]
[TestCase(@"""Joe\\tSmith"" email@domain.com")]
[TestCase(@"""Joe\""Smith"" email@domain.com")]
[TestCase(@"Test |<gaaf <email@domain.com>")]
[TestCase("MailTo:casesensitve@domain.com")]
[TestCase("mailto:email@domain.com")]
[TestCase("Joe Smith <mailto:email@domain.com>")]
[TestCase("Joe Smith <mailto:email(with comment)@domain.com>")]
[TestCase(@"""With extra < within quotes"" Display Name<email@domain.com>")]
[TestCase("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")]
public void IsValid(string email)
{
    Assert.IsTrue(EmailAddress.IsValid(email), email);
}

如果你正在使用FluentValidation,你可以写一些像这样简单的东西:

public cass User
{
    public string Email { get; set; }
}

public class UserValidator : AbstractValidator<User>
{
    public UserValidator()
    {
        RuleFor(x => x.Email).EmailAddress().WithMessage("The text entered is not a valid email address.");
    }
}

// Validates an user. 
var validationResult = new UserValidator().Validate(new User { Email = "açflkdj" });

// This will return false, since the user email is not valid.
bool userIsValid = validationResult.IsValid;

一般来说,使用正则表达式来验证电子邮件地址并不是一件容易的事情;在撰写本文时,电子邮件地址的语法必须遵循相对较多的标准,在正则表达式中实现所有这些标准实际上是不可行的!

我强烈建议你试试我们的EmailVerify。NET是一个成熟的。NET库,它可以根据当前所有的IETF标准(RFC 1123, RFC 2821, RFC 2822, RFC 3696, RFC 4291, RFC 5321和RFC 5322)验证电子邮件地址,测试相关的DNS记录,检查目标邮箱是否可以接受消息,甚至可以判断给定的地址是否是一次性的。

免责声明:我是这个组件的主要开发人员。