How to Send an Email with Verification link to user in Asp.net after registration

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 In this post I will try to explain how we can send the verification Email with link to user after registration in Asp.net.

Description:
In the previous article i have explained  How to Send Email with Attachment in Asp.net ,How to send Email in Asp.net using Web.config.

Here I created a table USER_REGISTRATION. USER_ID is primary key.

USER_ID	int
USERNAME	varchar(50)
FIRST_NAME	varchar(50)
LAST_NAME	varchar(50)
EMAIL	varchar(50)
IS_APPROVE	bit
PASSWORD	varchar(50)

Add two webforms to project User_registration.aspx and Verification.aspx.
Drag and drop the controls from Toolbox to .aspx page.

  <table border="1px solid" width="330px">

    <tr><b style="color:Blue;">Send Verification link to User after Registartion</b></tr>

    <tr><td>Username:</td><td>

        <asp:TextBox ID="txtusername" runat="server"></asp:TextBox></td></tr>

    <tr><td>First Name:</td><td>

        <asp:TextBox ID="txtfirst" runat="server"></asp:TextBox></td></tr>

    <tr><td>Last Name:</td><td>

        <asp:TextBox ID="txtlast" runat="server"></asp:TextBox></td></tr>

    <tr><td>Email:</td><td>

        <asp:TextBox ID="txtemail" runat="server"></asp:TextBox></td></tr>

    <tr><td>Password:</td><td>

        <asp:TextBox ID="txtpassword" runat="server" TextMode="Password"></asp:TextBox></td></tr>

    <tr><td>Confirm Password:</td><td>

        <asp:TextBox ID="txtconfirm" runat="server" TextMode="Password"></asp:TextBox></td></tr>

    <tr><td>&nbsp;</td><td>

        <asp:Button ID="Button1" runat="server" Text="Register" OnClientClick="return ValidateEmail();"

            onclick="Button1_Click" /></td></tr>

    </table>

Add the below given Javascript between Head Tag to validate the Email Textbox:

<script language="javascript" type="text/javascript">

         function ValidateEmail() {

             var emailRegex = new RegExp(/^([\w\.\-]+)@([\w\-]+)((\.(\w){2,3})+)$/i);

             var emailAddress = document.getElementById("<%= txtemail.ClientID %>").value;

             var valid = emailRegex.test(emailAddress);

             if (!valid) {

                 alert("Please Enter Valid Email address");

                 return false;

             } else

                 return true;

         }

  </script>

Now go to .aspx.cs page and write the below mention code:

using System.Data;

using System.Data.SqlClient;

using System.Configuration;

using System.Net.Mail;

using System.Net;

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["con"].ToString()); 

    protected void Page_Load(object sender, EventArgs e)

    {

        if (con.State == ConnectionState.Closed)

        {

            con.Open();

        }

    }

    protected void Button1_Click(object sender, EventArgs e)

    {

        if (IsUsernameEmailExist())

        {

           

            Messagebox("Username/Email address already exists. Please try another");

            return;

        }

        if (txtpassword.Text == txtconfirm.Text)

        {

            SqlCommand cmd = new SqlCommand("insert into USER_REGISTRATION (USERNAME,FIRST_NAME,LAST_NAME,EMAIL,PASSWORD) values(@USERNAME,@FIRST_NAME,@LAST_NAME,@EMAIL,@PASSWORD)", con);

            cmd.Parameters.AddWithValue("@USERNAME", txtusername.Text);

            cmd.Parameters.AddWithValue("@FIRST_NAME", txtfirst.Text);

            cmd.Parameters.AddWithValue("@LAST_NAME", txtlast.Text);

            cmd.Parameters.AddWithValue("@EMAIL", txtemail.Text);

            cmd.Parameters.AddWithValue("@PASSWORD", txtpassword.Text);

            cmd.ExecuteNonQuery();

            Sendemail();

            Clear();

            Messagebox("User Register Successfully");

            cmd.Dispose();

      

        }

        else

        {

            Messagebox("Passowrd Not Match");

        }                 

    }

    public void Sendemail()

    {

        string ActivationUrl;

        try

        {

            MailMessage message = new MailMessage();

            message.From = new MailAddress("demo@gmail.com", "Saklani");

            message.To.Add(txtemail.Text);

            message.Subject = "Verification Email";

            ActivationUrl = Server.HtmlEncode("http://localhost:9525/Important_Testing/Verification.aspx?USER_ID=" + GetUserID(txtemail.Text));

            message.Body = "<a href='"+ActivationUrl+"'>Click Here to verify your acount</a>";

            message.IsBodyHtml = true;

            SmtpClient smtp = new SmtpClient();

            smtp.Host = "smtp.gmail.com";

            smtp.Port = 587;

            smtp.Credentials = new System.Net.NetworkCredential("demo@gmail.com", "demo123");

            smtp.EnableSsl = true;

            smtp.Send(message);

        }

        catch (Exception ex)

        {

        }

    }

    private string GetUserID(string Email)

    {

        SqlCommand cmd = new SqlCommand("SELECT USER_ID FROM USER_REGISTRATION WHERE EMAIL=@EMAIL", con);     

        cmd.Parameters.AddWithValue("@EMAIL", txtemail.Text);

        string UserID = cmd.ExecuteScalar().ToString();

        return UserID;

    }

    private bool IsUsernameEmailExist()

    {

        SqlCommand cmd = new SqlCommand("Select * from USER_REGISTRATION where USERNAME='" + txtusername.Text + "' or EMAIL='" + txtemail.Text + "'", con);

        cmd.ExecuteNonQuery();

        DataTable dt = new DataTable();

        SqlDataAdapter adp = new SqlDataAdapter(cmd);

        adp.Fill(dt);

        if (dt.Rows.Count > 0)

        {

            return true;

        }

        else

        {

            return false;

        }

    }

    private void Messagebox(string Message)

    {

        Label lblMessageBox = new Label();

        lblMessageBox.Text =

            "<script language='javascript'>" + Environment.NewLine +

            "window.alert('" + Message + "')</script>";

        Page.Controls.Add(lblMessageBox);

    }

  public void Clear()

    {

        txtusername.Text = "";

        txtfirst.Text = "";

        txtlast.Text = "";

        txtemail.Text = "";

        txtpassword.Text = "";

        txtconfirm.Text = "";

    }

In VB (.aspx.vb)

Imports System.Data

Imports System.Data.SqlClient

Imports System.Configuration

Imports System.Net.Mail

Dim con As New SqlConnection(ConfigurationManager.ConnectionStrings("con").ToString())

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        If con.State = ConnectionState.Closed Then

            con.Open()

        End If

    End Sub

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click

        If IsUsernameEmailExist() Then

            Messagebox("Username/Email address already exists. Please try another")

            Return

        End If

        If txtpassword.Text = txtconfirm.Text Then

            Dim cmd As New SqlCommand("insert into USER_REGISTRATION (USERNAME,FIRST_NAME,LAST_NAME,EMAIL,PASSWORD) values(@USERNAME,@FIRST_NAME,@LAST_NAME,@EMAIL,@PASSWORD)", con)

            cmd.Parameters.AddWithValue("@USERNAME", txtusername.Text)

            cmd.Parameters.AddWithValue("@FIRST_NAME", txtfirst.Text)

            cmd.Parameters.AddWithValue("@LAST_NAME", txtlast.Text)

            cmd.Parameters.AddWithValue("@EMAIL", txtemail.Text)

            cmd.Parameters.AddWithValue("@PASSWORD", txtpassword.Text)

            cmd.ExecuteNonQuery()

            Sendemail()

            Messagebox("User Register Successfully")

            cmd.Dispose()

        Else

            Messagebox("Passowrd Not Match")

        End If

    End Sub

    Private Function IsUsernameEmailExist() As Boolean

        Dim cmd As New SqlCommand(("Select * from USER_REGISTRATION where USERNAME='" + txtusername.Text & "' or EMAIL='") + txtemail.Text & "'", con)

        cmd.ExecuteNonQuery()

        Dim dt As New DataTable()

        Dim adp As New SqlDataAdapter(cmd)

        adp.Fill(dt)

        If dt.Rows.Count > 0 Then

            Return True

        Else

            Return False

        End If

    End Function

    Private Sub Messagebox(ByVal Message As String)

        Dim lblMessageBox As New Label()

        lblMessageBox.Text = "<script language='javascript'>" + Environment.NewLine & "window.alert('" & Message & "')</script>"

        Page.Controls.Add(lblMessageBox)

    End Sub

 

    Public Sub Sendemail()

        Dim ActivationUrl As String

        Try

            Dim message As New MailMessage()

            message.From = New MailAddress("demo@gmail.com", "Saklani")

            message.[To].Add(txtemail.Text)

            message.Subject = "Verification Email"

            ActivationUrl = Server.HtmlEncode("http://localhost:9525/Important_Testing/Verification.aspx?USER_ID=" & GetUserID(txtemail.Text))

            message.Body = "<a href='" & ActivationUrl & "'>Click Here to verify your acount</a>"

            message.IsBodyHtml = True

            Dim smtp As New SmtpClient()

            smtp.Host = "smtp.gmail.com"

            smtp.Port = 587

            smtp.Credentials = New System.Net.NetworkCredential("demo@gmail.com", "demo123")

            smtp.EnableSsl = True

            smtp.Send(message)

        Catch ex As Exception

        End Try

    End Sub

    Private Function GetUserID(ByVal Email As String) As String

        Dim cmd As New SqlCommand("SELECT USER_ID FROM USER_REGISTRATION WHERE EMAIL=@EMAIL", con)

        cmd.Parameters.AddWithValue("@EMAIL", txtemail.Text)

        Dim UserID As String = cmd.ExecuteScalar().ToString()

        Return UserID

    End Function

After that now check the QueryString value on Verification.aspx page. Write the below given code on .aspx.cs page:

using System.Data;

using System.Data.SqlClient;

using System.Configuration;

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["con"].ToString());

    string USERID, USERNAME;

    protected void Page_Load(object sender, EventArgs e)

    {

        if (Request.QueryString["USER_ID"] != null)

        {

            USERID = Request.QueryString["USER_ID"];

            SqlCommand cmd = new SqlCommand("Update USER_REGISTRATION set IS_APPROVE=1 where USER_ID=@USER_ID", con);

            cmd.Parameters.AddWithValue("@USER_ID", USERID);          

            con.Open();

            cmd.ExecuteNonQuery();

            Response.Write(Request.QueryString["USER_ID"]);

        }

    }

In VB (.aspx.vb)

Imports System.Data

Imports System.Data.SqlClient

Private con As New SqlConnection(ConfigurationManager.ConnectionStrings("con").ToString())

    Private USERID As String, USERNAME As String

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        If Request.QueryString("USER_ID") IsNot Nothing Then

            USERID = Request.QueryString("USER_ID")

            Dim cmd As New SqlCommand("Update USER_REGISTRATION set IS_APPROVE=1 where USER_ID=@USER_ID", con)

            cmd.Parameters.AddWithValue("@USER_ID", USERID)

            con.Open()

            cmd.ExecuteNonQuery()

            Response.Write(Request.QueryString("USER_ID"))

        End If

    End Sub

Now run the project and check the result.

Download the project: