You can use the following code snippet to validate an email address.
Create a new windows application of vb.net and place a textbox named textbox1 and a button. on the click of that button paste the following code
ChkValidEmail(TextBox1.Text)
' Now paste the following code
Public Function ChkValidEmail(ByVal Value As String, Optional ByVal MaxLength As Integer = 255, Optional ByVal IsRequired As Boolean = True) As Boolean
If Value Is Nothing OrElse Value.Length = 0 Then
Return Not IsRequired
ElseIf Value.Length > MaxLength Then
Return False
End If
If Not System.Text.RegularExpressions.Regex.IsMatch(Value, "^[-A-Za-z0-9_@.]+$") Then
MsgBox(" Invalid character in the e-mail address. Only(A-Z,a-z,_,0-9,@,.)is valid. ")
TextBox1.Clear()
TextBox1.Focus()
Return False
End If
' search the @ char
Dim i As Integer = Value.IndexOf("@"c)
' there must be at least three chars after the @
If i <= 0 Or i >= Value.Length - 3 Then
MsgBox("INVALID E-Mail: '@' missing.")
TextBox1.Clear()
TextBox1.Focus()
Exit Function
End If
' ensure there is only one @ char
If Value.IndexOf("@"c, i + 1) >= 0 Then
MsgBox(" INVALID E-Mail: '@'Cann't be allowed twice.")
TextBox1.Clear()
TextBox1.Focus()
Exit Function
End If
' check that the domain portion contains at least one dot
Dim j As Integer = Value.LastIndexOf("."c)
' it can't be before or immediately after the @ char
If j < 0 Or j <= i + 1 Then
MsgBox(" INVALID E-Mail: '.' missing. ")
TextBox1.Clear()
TextBox1.Focus()
Exit Function
End If
' if we get here the address if validated
MsgBox(" Congratulations Operator:- Entered E-Mail Address is valid. ")
Return True
End Function
Summary
By this code u can easily validate the e-mail entered in the textbox
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| Author: Rajesh Panda 22 Nov 2004 | Member Level: Bronze Points : 0 |
Dear Friends,
There is small bug in this program.That is after successful validation of the email address the address has been cleared.so just ignore the last 2 lines of the code.
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| Author: Babu Aboobacker 23 Mar 2005 | Member Level: Silver Points : 0 |
I have got a simple Regex string from MSDN for validating email id.
private bool IsValidEmail(string strIn)
{
// Return true if strIn is in valid e-mail format.
return System.Text.RegularExpressions.Regex.IsMatch(strIn, @"^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$"); }
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