First you need to add the reference to the system.net. After adding the reference, add the following source code in the default.aspx shown as follows:

<table>

<tr>

<td colspan="2" align="center">Sending mail using asp.net</td>

</tr>

<tr><td>From:</td>

<td><asp:textbox id="FromTextBox" runat="server"></asp:textbox></td>

</tr>

<tr>
<td>To:</td>
<td><asp:textbox id="ToTextBox" runat="server"></asp:textbox></td>

</tr>

<tr>

<td>Subject:</td>

<td><asp:textbox id="SubTextBox" runat="server"></asp:textbox></td>

</tr>

<tr>

<td>Body:</td>

<td><asp:textbox id="BodyTextBox" textmode="MultiLine" runat="server" rows="10" columns="20"></asp:textbox></td>

</tr>

<tr>

<td>File Attachment:</td>

<td><asp:fileupload id="fuAttachment" runat="server" /></td>

</tr>

<tr>

<td colspan="2"><asp:button id="SubmitButton" runat="server" text="Submit" onclick="SubmitButton_Click" /> <asp:label id="ResultLabel" runat="server"></asp:label></td>

</tr>

</table>

And add the code behind as follows, in the default.aspx.cs

protected void SubmitButton_Click(object sender, EventArgs e)

{

try

{

using (MailMessage mm = new MailMessage(FromTextBox.Text, ToTextBox.Text, SubTextBox.Text, BodyTextBox.Text))

{

if (fuAttachment.HasFile)

{

string filename = Path.GetFileName(fuAttachment.PostedFile.FileName);

mm.Attachments.Add(new Attachment(fuAttachment.PostedFile.InputStream, filename));

}

mm.IsBodyHtml = false;

SmtpClient smtp = new SmtpClient();

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

smtp.EnableSsl = true;

NetworkCredential netcred = new NetworkCredential("honey.chawla21", "@postpade@");

smtp.UseDefaultCredentials = true;

smtp.Credentials = netcred;

smtp.Port = 587;

smtp.Send(mm);

ClientScript.RegisterStartupScript(GetType(), "alert", "alert('Email Sent');", true);

}

}

catch (Exception ex)

{

ResultLabel.Text = ex.Message.ToString();

}

}


After adding all these codes, just run this code by pressing F5 and see the result.