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如何使用 .NET Framework 验证电子邮件地址格式？

[英]How do I validate email address formatting with the .NET Framework?

 原文  2009-08-25 21:22:52  8   12    .net/ vb.net/ validation/ email

问题描述

我想要一个函数来测试字符串的格式是否像电子邮件地址。

.NET Framework 内置了什么来做到这一点？

这有效：

Function IsValidEmailFormat(ByVal s As String) As Boolean
    Try
        Dim a As New System.Net.Mail.MailAddress(s)
    Catch
        Return False
    End Try
    Return True
End Function

但是，有没有更优雅的方式呢？

12 个解决方案

解决方案1
 63 已采纳  2009-08-25 22:22:36

不要打扰你自己的验证。 .NET 4.0 通过MailAddress类显着改进了验证。 只需使用MailAddress address = new MailAddress(input) ，如果抛出，则无效。 如果您的输入有任何可能的解释为符合 RFC 2822 的电子邮件地址规范，它会解析它。 上面的正则表达式，即使是 MSDN 第一篇文章，也是错误的，因为它们没有考虑显示名称、引用的本地部分、域的域文字值、本地部分的正确点原子规范、邮件地址可以在尖括号中、显示名称的多个带引号的字符串值、转义字符、显示名称中的 unicode、注释和最大有效邮件地址长度。 我花了三个星期在 .NET 4.0 中为 System.Net.Mail 重新编写邮件地址解析器，相信我，这比提出一些正则表达式要困难得多，因为有很多边缘情况。 .NET 4.0 beta 2 中的MailAddress类将具有此改进功能。

还有一件事，您唯一可以验证的是邮件地址的格式。 如果不向该地址发送电子邮件并查看服务器是否接受发送，您就无法验证电子邮件地址实际上是否有效接收电子邮件。 这是不可能的，虽然您可以向邮件服务器提供 SMTP 命令以尝试对其进行验证，但很多时候这些命令将被禁用或返回不正确的结果，因为这是垃圾邮件发送者查找电子邮件地址的常用方法。

解决方案2
 8  2009-08-25 21:41:44

MSDN 文章：如何：验证字符串是否采用有效的电子邮件格式

此示例方法调用 Regex.IsMatch(String, String) 方法来验证字符串是否符合正则表达式模式。

Function IsValidEmailFormat(ByVal s As String) As Boolean
    Return Regex.IsMatch(s, "^([0-9a-zA-Z]([-\.\w]*[0-9a-zA-Z])*@([0-9a-zA-Z][-\w]*[0-9a-zA-Z]\.)+[a-zA-Z]{2,9})$")
End Function

解决方案3
 3  2013-10-07 15:17:49

'-----------------------------------------------------------------------

'Creater : Rachitha Madusanka

'http://www.megazoon.com

'jewandara@gmail.com

'jewandara@hotmail.com

'Web Designer and Software Developer

'@ http://www.zionx.net16.net

'-----------------------------------------------------------------------




Function ValidEmail(ByVal strCheck As String) As Boolean
    Try
        Dim bCK As Boolean
        Dim strDomainType As String


        Const sInvalidChars As String = "!#$%^&*()=+{}[]|\;:'/?>,< "
        Dim i As Integer

        'Check to see if there is a double quote
        bCK = Not InStr(1, strCheck, Chr(34)) > 0
        If Not bCK Then GoTo ExitFunction

        'Check to see if there are consecutive dots
        bCK = Not InStr(1, strCheck, "..") > 0
        If Not bCK Then GoTo ExitFunction

        ' Check for invalid characters.
        If Len(strCheck) > Len(sInvalidChars) Then
            For i = 1 To Len(sInvalidChars)
                If InStr(strCheck, Mid(sInvalidChars, i, 1)) > 0 Then
                    bCK = False
                    GoTo ExitFunction
                End If
            Next
        Else
            For i = 1 To Len(strCheck)
                If InStr(sInvalidChars, Mid(strCheck, i, 1)) > 0 Then
                    bCK = False
                    GoTo ExitFunction
                End If
            Next
        End If

        If InStr(1, strCheck, "@") > 1 Then 'Check for an @ symbol
            bCK = Len(Left(strCheck, InStr(1, strCheck, "@") - 1)) > 0
        Else
            bCK = False
        End If
        If Not bCK Then GoTo ExitFunction

        strCheck = Right(strCheck, Len(strCheck) - InStr(1, strCheck, "@"))
        bCK = Not InStr(1, strCheck, "@") > 0 'Check to see if there are too many @'s
        If Not bCK Then GoTo ExitFunction

        strDomainType = Right(strCheck, Len(strCheck) - InStr(1, strCheck, "."))
        bCK = Len(strDomainType) > 0 And InStr(1, strCheck, ".") < Len(strCheck)
        If Not bCK Then GoTo ExitFunction

        strCheck = Left(strCheck, Len(strCheck) - Len(strDomainType) - 1)
        Do Until InStr(1, strCheck, ".") <= 1
            If Len(strCheck) >= InStr(1, strCheck, ".") Then
                strCheck = Left(strCheck, Len(strCheck) - (InStr(1, strCheck, ".") - 1))
            Else
                bCK = False
                GoTo ExitFunction
            End If
        Loop
        If strCheck = "." Or Len(strCheck) = 0 Then bCK = False

ExitFunction:
        ValidEmail = bCK
    Catch ex As ArgumentException
        Return False
    End Try
    Return ValidEmail
End Function

解决方案4
 3  2014-11-20 10:50:21

    Public Function ValidateEmail(ByVal strCheck As String) As Boolean
        Try
            Dim vEmailAddress As New System.Net.Mail.MailAddress(strCheck)
        Catch ex As Exception
            Return False
        End Try
        Return True
    End Function

解决方案5
 2  2013-01-31 08:35:19

您首先必须通过输入错误的符号来限制用户，您可以使用文本框 KeyPress 事件来做到这一点

Private Sub txtemailid_KeyPress(ByVal sender As System.Object, 
                                ByVal e As System.Windows.FormsKeyPressEventArgs) Handles txtemailid.KeyPress

    Dim ac As String = "@"
    If e.KeyChar <> ChrW(Keys.Back) Then
        If Asc(e.KeyChar) < 97 Or Asc(e.KeyChar) > 122 Then
            If Asc(e.KeyChar) <> 46 And Asc(e.KeyChar) <> 95 Then
                If Asc(e.KeyChar) < 48 Or Asc(e.KeyChar) > 57 Then
                    If ac.IndexOf(e.KeyChar) = -1 Then
                        e.Handled = True

                    Else

                        If txtemailid.Text.Contains("@") And e.KeyChar = "@" Then
                            e.Handled = True
                        End If

                    End If


                End If
            End If
        End If

    End If

End Sub

上面的代码只允许用户输入 az(small), 0 to 9(digits), @,., _

并在使用文本框控件的验证事件以使用正则表达式验证电子邮件 ID 之后

Private Sub txtemailid_Validating(ByVal sender As System.Object, 
                                  ByVal e As System.ComponentModel.CancelEventArgs) 
    Handles txtemailid.Validating

    Dim pattern As String = "^[a-z][a-z|0-9|]*([_][a-z|0-9]+)*([.][a-z|0-9]+([_][a-z|0-9]+)*)?@[a-z][a-z|0-9|]*\.([a-z][a-z|0-9]*(\.[a-z][a-z|0-9]*)?)$"


    Dim match As System.Text.RegularExpressions.Match = Regex.Match(txtemailid.Text.Trim(), pattern, RegexOptions.IgnoreCase)
    If (match.Success) Then
        MessageBox.Show("Success", "Checking")
    Else
        MessageBox.Show("Please enter a valid email id", "Checking")
        txtemailid.Clear()
    End If
End Sub

解决方案6
 1  2009-08-25 21:28:00

您应该使用正则表达式来验证电子邮件地址。

解决方案7
 1  2020-01-31 10:52:29

检查电子邮件是否有效的另一个功能：

Public Function ValidEmail(ByVal strCheck As String) As Boolean
    Try
        Dim bCK As Boolean
        Dim strDomainType As String
        Const sInvalidChars As String = "!#$%^&*()=+{}[]|\;:'/?>,< "
        Dim i As Integer
        'Check to see if there is a double quote
        bCK = Not InStr(1, strCheck, Chr(34)) > 0
        If Not bCK Then GoTo ExitFunction
        'Check to see if there are consecutive dots
        bCK = Not InStr(1, strCheck, "..") > 0
        If Not bCK Then GoTo ExitFunction
        ' Check for invalid characters.
        If Len(strCheck) > Len(sInvalidChars) Then
            For i = 1 To Len(sInvalidChars)
                If InStr(strCheck, Mid(sInvalidChars, i, 1)) > 0 Then
                    bCK = False
                    GoTo ExitFunction
                End If
            Next
        Else
            For i = 1 To Len(strCheck)
                If InStr(sInvalidChars, Mid(strCheck, i, 1)) > 0 Then
                    bCK = False
                    GoTo ExitFunction
                End If
            Next
        End If

        If InStr(1, strCheck, "@") > 1 Then 'Check for an @ symbol
            bCK = Len(Left(strCheck, InStr(1, strCheck, "@") - 1)) > 0
        Else
            bCK = False
        End If
        If Not bCK Then GoTo ExitFunction
        strCheck = Right(strCheck, Len(strCheck) - InStr(1, strCheck, "@"))
        bCK = Not InStr(1, strCheck, "@") > 0 'Check to see if there are too many @'s
        If Not bCK Then GoTo ExitFunction
        strDomainType = Right(strCheck, Len(strCheck) - InStr(1, strCheck, "."))
        bCK = Len(strDomainType) > 0 And InStr(1, strCheck, ".") < Len(strCheck)
        If Not bCK Then GoTo ExitFunction
        strCheck = Left(strCheck, Len(strCheck) - Len(strDomainType) - 1)
        Do Until InStr(1, strCheck, ".") <= 1
            If Len(strCheck) >= InStr(1, strCheck, ".") Then
                strCheck = Left(strCheck, Len(strCheck) - (InStr(1, strCheck, ".") - 1))
            Else
                bCK = False
                GoTo ExitFunction
            End If
        Loop
        If strCheck = "." Or Len(strCheck) = 0 Then bCK = False
ExitFunction:
        ValidEmail = bCK
    Catch ex As ArgumentException
        Return False
    End Try
    Return ValidEmail
End Function

如何使用它：

Private Sub TextBox2_KeyDown(sender As Object, e As KeyEventArgs) Handles TextBox2.KeyDown
    If e.KeyCode = Keys.Enter Then
        If TextBox2.Text = "" Then
            MsgBox("Write Down Your email and Press Enter") : TextBox2.Select()
        Else

            If ValidEmail(TextBox2.Text) Then ' to check if the email is valid or not
                   'do whatever
            Else
                MsgBox("Please Write Valid Email")
                TextBox2.Select()
            End If
        End If
    End If
End Sub

解决方案8
 0  2009-08-25 21:28:59

您可以使用正则表达式来执行此操作。

已经写了很多关于它的文章； 当我在 google 中搜索 'regex to validate email address': Find or Validate an Email Address 时出现了这个问题。

解决方案9
 0  2016-01-26 14:11:04

在这种情况下，我已经测试了批准的“答案”，它似乎不符合实际有效电子邮件地址的规范。 经过多次头痛，我发现这个正则表达式比微软做得好得多。

"(?:(?:\r\n)?[ \t])*(?:(?:(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t]" +
")+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|""(?:[^\""\r\\]|\\.|(?:(?:\r\n)?[ \t]))*""(?:(?:" +
"\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(" +
"?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|""(?:[^\""\r\\]|\\.|(?:(?:\r\n)?[ " +
"\t]))*""(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\0" +
"31]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\" +
"](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+" +
"(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:" +
"(?:\r\n)?[ \t])*))*|(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z" +
"|(?=[\[""()<>@,;:\\"".\[\]]))|""(?:[^\""\r\\]|\\.|(?:(?:\r\n)?[ \t]))*""(?:(?:\r\n)" +
"?[ \t])*)*\<(?:(?:\r\n)?[ \t])*(?:@(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\" +
"r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[" +
" \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)" +
"?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t]" +
")*))*(?:,@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[" +
" \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*" +
")(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t]" +
")+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*)" +
"*:(?:(?:\r\n)?[ \t])*)?(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+" +
"|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|""(?:[^\""\r\\]|\\.|(?:(?:\r\n)?[ \t]))*""(?:(?:\r" +
"\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:" +
"\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|""(?:[^\""\r\\]|\\.|(?:(?:\r\n)?[ \t" +
"]))*""(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031" +
"]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](" +
"?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?" +
":(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?" +
":\r\n)?[ \t])*))*\>(?:(?:\r\n)?[ \t])*)|(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?" +
":(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|""(?:[^\""\r\\]|\\.|(?:(?:\r\n)?" +
"[ \t]))*""(?:(?:\r\n)?[ \t])*)*:(?:(?:\r\n)?[ \t])*(?:(?:(?:[^()<>@,;:\\"".\[\] " +
"\000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|""(?:[^\""\r\\]|" +
"\\.|(?:(?:\r\n)?[ \t]))*""(?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>" +
"@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|""" +
"(?:[^\""\r\\]|\\.|(?:(?:\r\n)?[ \t]))*""(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t]" +
")*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\" +
""".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?" +
":[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[" +
"\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*|(?:[^()<>@,;:\\"".\[\] \000-" +
"\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|""(?:[^\""\r\\]|\\.|(" +
"?:(?:\r\n)?[ \t]))*""(?:(?:\r\n)?[ \t])*)*\<(?:(?:\r\n)?[ \t])*(?:@(?:[^()<>@,;" +
":\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([" +
"^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\""" +
".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\" +
"]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*(?:,@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\" +
"[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\" +
"r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] " +
"\000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]" +
"|\\.)*\](?:(?:\r\n)?[ \t])*))*)*:(?:(?:\r\n)?[ \t])*)?(?:[^()<>@,;:\\"".\[\] \0" +
"00-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|""(?:[^\""\r\\]|\\" +
".|(?:(?:\r\n)?[ \t]))*""(?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@," +
";:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|""(?" +
":[^\""\r\\]|\\.|(?:(?:\r\n)?[ \t]))*""(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t])*" +
"(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\""." +
"\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[" +
"^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\]" +
"]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*\>(?:(?:\r\n)?[ \t])*)(?:,\s*(" +
"?:(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\" +
""".\[\]]))|""(?:[^\""\r\\]|\\.|(?:(?:\r\n)?[ \t]))*""(?:(?:\r\n)?[ \t])*)(?:\.(?:(" +
"?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[" +
"\[""()<>@,;:\\"".\[\]]))|""(?:[^\""\r\\]|\\.|(?:(?:\r\n)?[ \t]))*""(?:(?:\r\n)?[ \t" +
"])*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t" +
"])+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?" +
":\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|" +
"\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*|(?:" +
"[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\"".\[\" +
"]]))|""(?:[^\""\r\\]|\\.|(?:(?:\r\n)?[ \t]))*""(?:(?:\r\n)?[ \t])*)*\<(?:(?:\r\n)" +
"?[ \t])*(?:@(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""" +
"()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)" +
"?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>" +
"@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*(?:,@(?:(?:\r\n)?[" +
" \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@," +
";:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t]" +
")*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\" +
""".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*)*:(?:(?:\r\n)?[ \t])*)?" +
"(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[""()<>@,;:\\""." +
"\[\]]))|""(?:[^\""\r\\]|\\.|(?:(?:\r\n)?[ \t]))*""(?:(?:\r\n)?[ \t])*)(?:\.(?:(?:" +
"\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[" +
"""()<>@,;:\\"".\[\]]))|""(?:[^\""\r\\]|\\.|(?:(?:\r\n)?[ \t]))*""(?:(?:\r\n)?[ \t])" +
"*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])" +
"+|\Z|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\" +
".(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z" +
"|(?=[\[""()<>@,;:\\"".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*\>(?:(" +
"?:\r\n)?[ \t])*))*)?;\s*)"

我已经使用一个简单的应用程序将其格式化为 vb 字符串。 太糟糕了，堆栈溢出对成为“编码存储库”更感兴趣，而不是拥有问题的完整答案。

解决方案10
 0  2016-09-28 07:34:18

像“address@localhost”和“user@192.168.1.2”这样的电子邮件实际上是有效的地址，您可以通过运行自己的电子邮件服务器来测试这些地址（通常也可以通过修改主机文件来完成）。 但是，对于完整的解决方案：

''' <summary>
''' METHODS FOR SENDING AND VALIDATING EMAIL
''' </summary>
''' <remarks></remarks>
Public Class email

    ''' <summary>
    ''' check if email format is valid
    ''' </summary>
    ''' <param name="emailAddress">[required] Email address.</param>
    ''' <param name="disallowLocalDomain">[optional] Allow headers like "@localhost"?</param>
    ''' <param name="allowAlerts">[optional] Enable error messages?</param>
    ''' <returns>Returns true if email is valid and false otherwise.</returns>
    ''' <remarks></remarks>
    Public Shared Function isValid(ByVal emailAddress As String,
                                   Optional ByVal disallowLocalDomain As Boolean = True,
                                   Optional ByVal allowAlerts As Boolean = True
                                   ) As Boolean
        Try
            Dim mailParts() As String = emailAddress.Split("@")
            If mailParts.Length <> 2 Then
                If allowAlerts Then
                    MsgBox("Valid email addresses are formatted [sample@domain.tld]. " &
                           "Your address is missing a header [i.e. ""@domain.tld""].",
                           MsgBoxStyle.Exclamation, "No Header Specified")
                End If
                Return False
            End If
            If mailParts(mailParts.GetLowerBound(0)) = "" Then
                If allowAlerts Then
                    MsgBox("Valid email addresses are formatted [sample@domain.tld]. " &
                           "The username portion of the e-mail address you provided (before the @ symbol) is empty.",
                           MsgBoxStyle.Exclamation, "Invalid Email User")
                End If
                Return False
            End If
            Dim headerParts() As String = mailParts(mailParts.GetUpperBound(0)).Split(".")
            If disallowLocalDomain AndAlso headerParts.Length < 2 Then
                If allowAlerts Then
                    MsgBox("Valid email addresses are formatted [sample@domain.tld]. " &
                           "Although addresses formatted like [sample@domain] are valid, " &
                           "only addresses with headers like ""sample.org"", ""sample.com"", and etc. " &
                           "[i.e. @domain.org] are accepted.",
                           MsgBoxStyle.Exclamation, "Invalid Header")
                End If
                Return False
            ElseIf headerParts(headerParts.GetLowerBound(0)) = "" Or
                   headerParts(headerParts.GetUpperBound(0)) = "" Then
                If allowAlerts Then
                    MsgBox("Valid email addresses are formatted [sample@domain.tld]. " &
                           "Your header """ & mailParts(mailParts.GetUpperBound(0)) & """ is invalid.",
                           MsgBoxStyle.Exclamation, "Invalid Header")
                End If
                Return False
            End If
            Dim address As MailAddress = New MailAddress(emailAddress)
        Catch ex As Exception
            If allowAlerts Then
                MsgBox(ex.Message, MsgBoxStyle.Exclamation, "Invalid Email Address")
            End If
            Return False
        End Try
        Return True
    End Function

End Class 'email'

解决方案11
 0  2022-12-23 00:36:23

我认为，尽可能避免经常遇到异常，并依靠它作为后备可能是一个低工作量、高信任度的好地方。 我对正则表达式不是很有经验，我不太信任它，所以我想提供一个比你的改进的解决方案......我添加了一个看起来最小长度为 5 的支票，并且它包含“@”，因为它是电子邮件中唯一一致的东西之一，应该能捕捉到任何明显不是电子邮件的东西。 虽然捕获异常是“坏的”并且如果您的应用程序似乎遇到更复杂的异常并且您必须关心资源使用情况可能会导致方法运行缓慢这应该可以帮助您接近您的解决方案，同时也很健壮到微软的库标准。 请注意，电子邮件的真正最小值是 3，我认为是“a@b”，但查看实际数据我在代码中使用了 5

Function IsValidEmailFormat(ByVal pMaybeEmail As String) As Boolean
    If pMaybeEmail.Contains("@") andAlso pMaybeEmail.Length() > 5 Then 

        ' most likely an email, but just in case
        Try
            Dim validEmail As New System.Net.Mail.MailAddress(pMaybeEmail)
            return True
        Catch
            return False
        End Try

    End If 
    Return False
End Function

在此处输入图像描述

解决方案12
 -1  2016-04-21 12:58:36

 Public Shared Function ValidEmailAddress(ByVal emailAddress As String, ByRef errorMessage As String) As Boolean
        If emailAddress.Length = 0 Then
            errorMessage = "E-mail address is required."
            Return False
        End If
        If emailAddress.IndexOf("@") > -1 Then
            If (emailAddress.IndexOf(".", emailAddress.IndexOf("@")) > emailAddress.IndexOf("@")) AndAlso emailAddress.Split(".").Length > 0 AndAlso emailAddress.Split(".")(1) <> "" Then
                errorMessage = ""
                Return True
            End If
        End If
        errorMessage = "E-mail address must be valid e-mail address format."
        Return False
    End Function

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