Valid Email ID with VB.Net

Valid Email ID , this program is designed to find out whether user input is like a email id or other.
How to valid email id with vb.net.

Working with Vb.net 2012 its easy and quite tough to handle the code.

This code work whether in vb.net or with vb 6.0. It is simple and combination of all codes like variables loop and conditions.

First of all Open the program. And place label ,textbox and command button to the form.

Provide name of the controls.
Textbox as txtbox
command as btnok   continue.................................


then you must visualize the email id to be.

Email Id is like abcd@gmail.com
It means there is @ in the middle , . dot after @ with some letters or number then some letters.
It is formatted   in mind to apply.

Here is a code to apply in btnok code.

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        On Error GoTo err
        Dim stra, strb, strc, strd As String
        Dim i, j As Integer
        strb = txtbox.Text
        stra = "!#$%^&*():;'<>,+="
        If txtbox.Text = "" Then
            MsgBox("Please Input Email-ID")
            Exit Sub
        Else
            For i = 1 To Len(strb)
                strc = Mid(strb, i, 1)
                For j = 1 To Len(strb)
                    strd = Mid(stra, j, 1)
                    If strc = strd Then
                        MsgBox(" Invalid Character !!!!!!", vbCritical + vbInformation)
                        txtbox.Focus()
                        txtbox.BackColor = Color.Brown
                        Exit Sub
                    End If
                Next
            Next
            Dim k, l, m As Integer
            Dim strrat, strdot As String
            For k = 1 To Len(strb)
                strrat = Mid(strb, k, 1)
                If strrat = "@" Then
                    For l = k To Len(strb)
                        strdot = Mid(strb, l + 1, 1)
                        If strdot = "." Then
                            If (Len(strb) - l) >= 3 Then
                                txtbox.BackColor = Color.White
                                MsgBox("Valid Email Address")
                                Exit Sub
                            Else
                                MsgBox("Invalid Email ID !!!!!!", vbCritical)
                                txtbox.Focus()
                                txtbox.BackColor = Color.Brown
                                Exit Sub
                            End If

                        End If
                    Next
                End If
            Next
        End If
        MsgBox("Invalid Email ID !!!!!!", vbCritical)
        txtbox.Focus()

        txtbox.BackColor = Color.Brown
        Exit Sub
err:
        MsgBox(Err.Description)
    End Sub

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Simple description about code.

In the first line.. i have checked whether there is error in the command ,if error then describe to last line.
In the second and third line i have assigned variables necessary to check the input data.

Then i have checked whether the textbox is empty or filled with. If empty then error message
MsgBox("Please Input Email-ID")

Then i have checked the invalid characters  using loop.
Using loop if condition ,if true then go to the next loop of finding @.
After then checking . dot and letters with. then
all format will be checked.

Lets see by running the project.

Press buttons

Results

again,

Results





Thank You.

Please comment if any questions.