Handy ASP.NET Email Control

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Introduction

Most websites have the need for some sort of "feedback form" or "email-us" page, which, as we know, is tedious to re-develop on every site, even in .NET. I have developed this simple E-Mail control in VB.NET that can be wrapped around any form to be turned into an email form, even with file inputs.

The first major thing to overcome is the <ParseChildren(False)> property which must be set just above the CLASS in the .ascx.vb file (no extra linebreaks). This allows the User Control to access the controls on the .aspx page where it is used.

    <ParseChildren(False)> _ 'No extra linebreak after this!!

        Public MustInherit Class MailAnything
        Inherits System.Web.UI.UserControl

If you do have a file input on your web form remember to set the enctype="multipart/form-data".

Another important thing to remember is to use Web Forms Labels to name your fields on the web form so that it can be read by your user control and form part of the email.

The basic elements of the form in the .aspx file is as follows (example).

<Bluegrass:Mailer Mailto="you@you.com" runat="server"> 
 <table border="0" ID="Table1"> 
  <tr> 
   <td align="right" valign="top"> 
    <asp:Label ID="lblFirstname" Runat="server" /> 
   </td> 
   <td> 
    <asp:TextBox CssClass="input" ID="txtFirstname" Runat="server" /> 
   </td> 
  </tr> 
  <tr> 
   <td align="right" valign="top"> 
    <asp:Label ID="lblLastname" Runat="server" /> 
   </td> 
   <td> 
    <asp:TextBox CssClass="input" ID="txtLastname" Runat="server" /> 
   </td> 
  </tr> 
  <tr> 
   <td align="right" valign="top"> 
    <asp:Label ID="lblDescription" Runat="server" /> 
   </td> 
   <td> 
    <asp:TextBox CssClass="input" ID="txtDescription" TextMode="MultiLine"
      Runat="server" /> 
   </td> 
  </tr> 
  <tr>
   <td align="right" valign="top"> 
    <asp:Label ID="lblAge" Runat="server" /> 
   </td> 
   <td> 
    <asp:DropDownList CssClass="input" ID="selAge" Runat="server" /> 
   </td> 
  </tr> 
  <tr> 
   <td align="right" valign="top"> 
    <asp:Label ID="lblfile" Runat="server" /> 
   </td> 
   <td> 
    <input CssClass="input" type="file" id="FileInput" runat="server"
      NAME="FileInput"> 
   </td> 
  </tr> 
  <tr> 
   <td align="right" valign="top"> 
    <asp:Label ID="lblReply" Runat="server" /> 
   </td> 
   <td> 
    <asp:CheckBox ID="chkReply" Runat="server" /> 
   </td> 
  </tr> 
 </table> 
</Bluegrass:Mailer> 

Also don't forget to register your User control in the .aspx file

<%@ Register TagPrefix="Bluegrass" TagName="Mailer"
  Src="controls/MailAnything.ascx" %>

The rest is then all done in the user control which can be re-used in any project. Here is how I did the user control:

Imports System
Imports System.Collections
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.ComponentModel
Imports System.Web.Mail
Imports System.Text

Namespace Bluegrass.Mail

    <ParseChildren(False)> _ 'No extra linebreak after this!!

        Public MustInherit Class MailAnything
        Inherits System.Web.UI.UserControl
        'Add your button so that it doesn't need to be done in the aspx side

        Protected WithEvents btnMail As Button
        Protected lblSent As Label
        'Declare this public string so that the "mail to" address can be set
        'in the aspx page

        Public Mailto As String

#Region " Web Form Designer Generated Code "
#End Region

        Private Sub Page_Load(ByVal sender As System.Object, _
          ByVal e As System.EventArgs) Handles MyBase.Load
            'Empty            

        End Sub

        Private Sub RegisterBtn_Click(ByVal sender As System.Object, _
          ByVal e As System.EventArgs) Handles btnMail.Click
            'Set random counter

            Dim iCount As Integer = 0
            'Set control counter

            Dim iControlCount As Integer
            'Dim filename in case there are files to email

            Dim sFileNameOnly As String

            Dim sControl As String
            Dim sBody As StringBuilder = New StringBuilder()
            'Count the controls

            iControlCount = Controls.Count
            'Loop through each control to add to message body

            Do While iCount < (iControlCount - 1)
              'do not include "lblSent" in the body

              If Not Controls(iCount).ID = "lblSent" Then
                Select Case Controls(iCount).GetType().Name
                  Case "HtmlInputFile"
                    'If there is a file to email then save the file
                    'to disk

                    Dim currentControl As HtmlInputFile = Controls(iCount)
                    If Len(currentControl.PostedFile.FileName) > 0 Then
                      Dim iFileNameLength As Integer
                      Dim PostedFile = currentControl.PostedFile
                      Dim sFileNamePath As String
                      sFileNamePath = currentControl.PostedFile.FileName
                      iFileNameLength = InStr(1, StrReverse(sFileNamePath), _
                        "\")
                      sFileNameOnly = Mid(sFileNamePath, _
                        (Len(sFileNamePath) - iFileNameLength) + 2)
                      currentControl.PostedFile.SaveAs(_
                        Server.MapPath("\MailTS\uploaded\" & sFileNameOnly))
                    End If
                  Case "TextBox"
                    Dim currentControl As TextBox = Controls(iCount)
                    sBody.AppendFormat("{0} <br />", currentControl.Text)
                  Case "Label"
                    Dim currentControl As Label = Controls(iCount)
                    sBody.AppendFormat("{0} ", currentControl.Text)
                  Case "DropDownList"
                    Dim currentControl As DropDownList = Controls(iCount)
                    sBody.AppendFormat("{0} <br />", _
                      currentControl.SelectedItem.Text)
                  Case "CheckBox"
                    Dim currentControl As CheckBox = Controls(iCount)
                    If currentControl.Checked Then
                      sBody.AppendFormat("{0} <br />", "Yes")
                    Else
                      sBody.AppendFormat("{0} <br />", "No")
                    End If
                End Select
              End If
              'Increment random counter
              iCount = iCount + 1
            Loop

            'Dim mail message
            Dim mailCurrent As New MailMessage()
            'Assign mail attributes
            mailCurrent.Body = sBody.ToString()
            mailCurrent.To = Mailto
            mailCurrent.From = Mailto
            mailCurrent.BodyFormat = MailFormat.Html
            'If there is a file to mail add it to the email
            If Len(sFileNameOnly) > 0 Then
              mailCurrent.Attachments.Add(_
                New System.Web.Mail.MailAttachment(_
                  Server.MapPath("\MailTS\uploaded\" & sFileNameOnly)))
            End If
            'Set SMTP server to localhost
            SmtpMail.SmtpServer = "localhost"
            'Send mail
            SmtpMail.Send(mailCurrent)
            'Assign text to say mail was sent
            lblSent.Text = "Your mail was sent to: " & Mailto
         End Sub
        
        'Some extra formatting
        Protected Overrides Sub RenderChildren(ByVal output As HtmlTextWriter)
          If HasControls() Then
            Dim iCount As Integer = 3
            Dim iControlCount As Integer

            iControlCount = Controls.Count

            Do While iCount < (iControlCount - 1)
              Controls(iCount).RenderControl(output)
              iCount = iCount + 1
            Loop

            Controls(0).RenderControl(output)
            Controls(1).RenderControl(output)
            Controls(2).RenderControl(output)
          End If
        End Sub
    End Class
End Namespace