Newbie: Input Form Problem

[kwilliams]

I have an ASP.NET (2.0) input form that submits user data to a DB table using a stored procedure only after the ASP.NET validations have been met. Once the page is valid, the form disappears to the user, and they instead see a confirmation message.It works great, except for if I then push the refresh button on that same page. If I do that, the stored procedure is run again, and the data is re-submitted to the DB table.I know that I'm missing a simple step in this, but I'm not sure how to proceed. I've included all of the related code below. Any and all help would be appreciated.feedback.aspx.vb:

Imports System.Data.SqlClientPartial Class forms_feedback	Inherits System.Web.UI.Page	Private ds As New DataSet()	Private conn As SqlConnection	Private cmd As New SqlCommand()	Sub SubmitBtn_Click(ByVal Sender As Object, ByVal E As EventArgs)		'Declare form variables		Dim category_form As String = selectCategory.SelectedItem.Value		Dim address_form As String = txtAddress.Text		Dim fullname_form As String = txtFullName.Text		Dim city_form As String = txtCity.Text		Dim state_form As String = selectState.SelectedItem.Value		Dim zipcode_form As String = txtZipCode.Text		Dim email_form As String = txtEmailAddress.Text		Dim phone_form As String = txtPhone.Text		Dim comments_form As String = txtComments.Text		'Assign date variables		Dim dtCurrDate As DateTime = DateTime.Now 'Assign current date		Dim strDateTimeISO As String = dtCurrDate.ToString("s") 'ISO format		hfDateTime.Value = strDateTimeISO		Session("SubmitTime") = dtCurrDate.ToString("t")		'Assign server variables		hfRemoteAddr.Value = Request.ServerVariables("REMOTE_ADDR")		hfRemoteHost.Value = Request.ServerVariables("REMOTE_HOST")		If Page.IsValid Then			'Display confirmation message			lblOutput.Text = "Thank you for completing the Feedback Form. If contact was requested, you should be contacted by someone within 1-3 days during normal business hours."			'Insert into database			conn = New SqlConnection("server=SERVERNAME;database=DBNAME;uid=USERNAME;pwd=PASSWORD")			cmd = New SqlCommand("spFeedback", conn)			cmd.CommandType = CommandType.StoredProcedure			'Assign form paramaters			cmd.Parameters.Add("@category_id", SqlDbType.VarChar, 16).Value = category_form			cmd.Parameters.Add("@fullname", SqlDbType.VarChar, 50).Value = fullname_form			cmd.Parameters.Add("@address", SqlDbType.VarChar, 50).Value = address_form			cmd.Parameters.Add("@city", SqlDbType.VarChar, 50).Value = city_form			cmd.Parameters.Add("@state", SqlDbType.VarChar, 2).Value = state_form			cmd.Parameters.Add("@zipcode", SqlDbType.VarChar, 10).Value = zipcode_form			cmd.Parameters.Add("@email", SqlDbType.VarChar, 75).Value = email_form			cmd.Parameters.Add("@phone", SqlDbType.VarChar, 20).Value = phone_form			cmd.Parameters.Add("@comments", SqlDbType.VarChar, 1000).Value = comments_form			cmd.Parameters.Add("@remoteaddr", SqlDbType.VarChar, 20).Value = hfRemoteAddr.Value			cmd.Parameters.Add("@remotehost", SqlDbType.VarChar, 20).Value = hfRemoteHost.Value			cmd.Parameters.Add("@datetime", SqlDbType.VarChar, 50).Value = hfDateTime.Value			conn.Open()			cmd.ExecuteNonQuery()			conn.Close()		End If	End SubEnd Class

feedback.aspx:

<%@ Page Language="VB" MasterPageFile="~/MasterPage.master" CodeFile="feedback.aspx.vb" Inherits="forms_feedback" AutoEventWireup="true" title="Feedback Form" %><asp:content id="Content1" contentplaceholderid="ContentPlaceHolder1" runat="server">	<asp:label id="lblOutput" runat="server" /><br />	<% If Not Page.IsPostBack Then %>		<form name="formFeedback" action="" method="post" runat="server">			<asp:ValidationSummary ID="valSummary" runat="server"		   	 HeaderText="You must fix the following form entries:"		   	 Font-Names="verdana" 		   	 Font-Size="10pt"				Font-Bold="True" 			/>			<br />		<table class="tableborder_black" width="98%" id="Feedback Form">			<tbody>				<tr class="tablecell_black">					<th scope="col" colspan="2">Feedback Form</th>				</tr>				<tr>					<td class="tablecell1" align="right" valign="top">Category</td>					<td class="tablecell3">						<asp:DropDownList id="selectCategory" runat="server">							<asp:ListItem Value="general" Text="General" Selected="True" />							<asp:ListItem Value="cat1" Text="Category 1" />							<asp:ListItem Value="cat2" Text="Category 2" />							<asp:ListItem Value="cat3" Text="Category 3" />						</asp:DropDownList>					</td>				</tr>				<tr>					<td class="tablecell1" align="right" valign="top" style="height: 26px">Full Name</td>					<td class="tablecell3" style="height: 26px">						<asp:Textbox id="txtFullName" columns="20" runat="server" />						<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ErrorMessage="Allowed characters: A-Z, a-z,  and dashes (-)." ValidationExpression="^[a-zA-Z-]{0,50}$" ControlToValidate="txtFullName"></asp:RegularExpressionValidator>					</td>				</tr>				<tr>					<td class="tablecell1" align="right" valign="top">Address</td>					<td class="tablecell3"><asp:Textbox id="txtAddress" columns="20" runat="server" />						<asp:RegularExpressionValidator ID="RegularExpressionValidator2" runat="server" ControlToValidate="txtAddress"							ErrorMessage="Allowed characters: 0-9, A-Z, a-z, dashes (-), periods (.), and number signs (#)." ValidationExpression="^[a-zA-Z0-9 \.#-/]{0,50}$"></asp:RegularExpressionValidator>					</td>				</tr>				<tr>					<td class="tablecell1" align="right" valign="top">City</td>					<td class="tablecell3"><asp:Textbox id="txtCity" columns="20" runat="server" />						<asp:RegularExpressionValidator ID="RegularExpressionValidator3" runat="server" ControlToValidate="txtCity"							ErrorMessage="Allowed characters: A-Z, a-z, dashes (-), and periods (.)." ValidationExpression="^[a-zA-Z \.-]{0,50}$"></asp:RegularExpressionValidator>					</td>				</tr>				<tr>					<td class="tablecell1" align="right" valign="top">State</td>					<td class="tablecell3">						<!--<asp:DropDownList id="stateoption" runat="server" />						<br />-->						<asp:DropDownList id="selectState" runat="server">							<asp:ListItem Value="" Text="- Select -" Selected="true" />							<asp:ListItem Value="AK" Text="Arkansas" />							<asp:ListItem Value="AL" Text="Alabama" />							<asp:ListItem Value="AR" Text="Arkansas" />							<asp:ListItem Value="AZ" Text="Arizona" />							<asp:ListItem Value="CA" Text="California" />							<asp:ListItem Value="CO" Text="Colorado" />							<asp:ListItem Value="CT" Text="Connecticut" />							<asp:ListItem Value="DE" Text="Deleware" />							<asp:ListItem Value="FL" Text="Florida" />							<asp:ListItem Value="GA" Text="Georgia" />							<asp:ListItem Value="HI" Text="Hawaii" />							<asp:ListItem Value="IA" Text="Iowa" />							<asp:ListItem Value="ID" Text="Idaho" />							<asp:ListItem Value="IL" Text="Illinois" />							<asp:ListItem Value="IN" Text="Indiana" />							<asp:ListItem Value="KS" Text="Kansas" />							<asp:ListItem Value="KY" Text="Kentucky" />							<asp:ListItem Value="LA" Text="Louisiana" />							<asp:ListItem Value="MA" Text="Massachusetts" />							<asp:ListItem Value="MD" Text="Maryland" />							<asp:ListItem Value="ME" Text="Maine" />							<asp:ListItem Value="MI" Text="Michigan" />							<asp:ListItem Value="MN" Text="Minnesota" />							<asp:ListItem Value="MO" Text="Missouri" />							<asp:ListItem Value="MS" Text="Mississippi" />							<asp:ListItem Value="MT" Text="Montana" />							<asp:ListItem Value="NC" Text="North Carolina" />							<asp:ListItem Value="ND" Text="North Dakota" />							<asp:ListItem Value="NE" Text="Nebraska" />							<asp:ListItem Value="NH" Text="New Hampshire" />							<asp:ListItem Value="NJ" Text="New Jersey" />							<asp:ListItem Value="NM" Text="New Mexico" />							<asp:ListItem Value="NV" Text="Nevada" />							<asp:ListItem Value="NY" Text="New York" />							<asp:ListItem Value="OH" Text="Ohio" />							<asp:ListItem Value="OK" Text="Oklahoma" />							<asp:ListItem Value="OR" Text="Oregon" />							<asp:ListItem Value="PA" Text="Pennsylvania" />							<asp:ListItem Value="RI" Text="Rhode Island" />							<asp:ListItem Value="SC" Text="South Carolina" />							<asp:ListItem Value="SD" Text="South Dakota" />							<asp:ListItem Value="TN" Text="Tennessee" />							<asp:ListItem Value="TX" Text="Texas" />							<asp:ListItem Value="UT" Text="Utah" />							<asp:ListItem Value="VA" Text="Virginia" />							<asp:ListItem Value="VT" Text="Vermont" />							<asp:ListItem Value="WA" Text="Washington" />							<asp:ListItem Value="DC" Text="Washington D.C." />							<asp:ListItem Value="WI" Text="Wisconsin" />							<asp:ListItem Value="WV" Text="West Virginia" />							<asp:ListItem Value="WY" Text="Wyoming" />							<asp:ListItem Value="OT" Text="Other (specify in comments)" />						</asp:DropDownList>						<asp:RequiredFieldValidator ID="RequiredFieldValidator2" ControlToValidate="selectState" runat="server"							ErrorMessage="Must select a state."></asp:RequiredFieldValidator>					</td>				</tr>				<tr>					<td class="tablecell1" align="right" valign="top" style="height: 26px">Zip Code</td>					<td class="tablecell3" style="height: 26px"><asp:Textbox id="txtZipCode" columns="20" runat="server" />						<asp:RegularExpressionValidator ID="RegularExpressionValidator4" runat="server" ControlToValidate="txtZipCode"							ErrorMessage="Zip code must be valid (Format: xxxxx or xxxxx-xxxx)." ValidationExpression="\d{5}(-\d{4})?"></asp:RegularExpressionValidator>					</td>				</tr>				<tr>					<td class="tablecell1" align="right" valign="top">Email Address</td>					<td class="tablecell3"><asp:Textbox id="txtEmailAddress" columns="20" runat="server" />						<asp:RegularExpressionValidator ID="RegularExpressionValidator5" runat="server" ControlToValidate="txtEmailAddress"							ErrorMessage="Email must be valid (Format: you@domain.com)." ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"></asp:RegularExpressionValidator>					</td>				</tr>				<tr>					<td class="tablecell1" align="right" valign="top">Phone</td>					<td class="tablecell3"><asp:Textbox id="txtPhone" columns="20" runat="server" />						<asp:RegularExpressionValidator ID="RegularExpressionValidator7" runat="server" ControlToValidate="txtPhone"						ErrorMessage="Phone number must be valid (Format: xxx-xxx-xxxx)." ValidationExpression="((\(\d{3}\) ?)|(\d{3}-))?\d{3}-\d{4}"></asp:RegularExpressionValidator>					</td>				</tr>				<tr>					<td class="tablecell1" align="right" valign="top" style="height: 50px">Comments</td>					<td class="tablecell3" style="height: 50px">						<asp:TextBox ID="txtComments" Columns="40" Rows="4" runat="server" Height="60px" TextMode="MultiLine"></asp:TextBox>						<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="txtComments"							ErrorMessage="Must enter comments to complete this form." Display="Dynamic"></asp:RequiredFieldValidator>						<asp:RegularExpressionValidator ID="RegularExpressionValidator8" runat="server" ControlToValidate="txtComments"							ErrorMessage="Must enter between 5 and 1000 characters." ValidationExpression="^[a-zA-Z-0-9]{5,1000}$" Display="Dynamic"></asp:RegularExpressionValidator>					</td>				</tr>				<tr class="tablecell_black">					<td scope="col" colspan="2" align="center">						<asp:HiddenField ID="hfRemoteAddr" runat="server" />						<asp:HiddenField ID="hfRemoteHost" runat="server" />						<asp:HiddenField ID="hfDateTime" runat="server" />						<input id="btnReset" type="Reset" runat="server">						<asp:Button ID="btnSubmit" Text="Submit" OnClick="SubmitBtn_Click" runat="server" />					</td>				</tr>				</tbody>			</table>		</form>	<% End If %>	  </asp:content>

[jesh]

One solution is to handle all of the Postback (validate request, update database, etc.) and then, when everything looks right, Response.Redirect the user to a separate confirmation page.

[kwilliams]

One solution is to handle all of the Postback (validate request, update database, etc.) and then, when everything looks right, Response.Redirect the user to a separate confirmation page.

I was originally doing that exact solution, but I really want to learn how to handle all of these tasks on one page. Any suggestion on how to do that?

[jesh]

Well, you can't stop people from refreshing their browsers. Another solution would be to assign a unique id (GUIDs work, but you can come up with your own solution) to the page on post back and store that id somewhere - cookie, session, database, application cache, viewstate, etc.Additionally, on post back, check for the presence of that unique id. If it is there, don't accept the post back (it would mean that the page had been posted back before). If it isn't there, accept the post back and then store that unique id somewhere.

[aspnetguy]

I simple solution would be when the form is accepted into the database redirect to the same page be add a flag to the url to indicate that a confirmation message should be shown. that way you are still handling it ont he saem page and the post data gets cleared.feedback.aspx.vb

Imports System.Data.SqlClientPartial Class forms_feedback	Inherits System.Web.UI.Page	Private ds As New DataSet()	Private conn As SqlConnection	Private cmd As New SqlCommand()	Sub Page_Load(ByVal Sender As Object, ByVal E As EventArgs)	   Dim flag As String	   flag = Request.QueryString("message")	   If Not String.IsNullOrEmpty(flag) And flag = "1" Then		  'Show your confirmation message here	   End If	End Sub	Sub SubmitBtn_Click(ByVal Sender As Object, ByVal E As EventArgs)		'...		If Page.IsValid Then			'...			conn.Open()			cmd.ExecuteNonQuery()			conn.Close()			Response.Redirect("feedback.aspx?message=1")		End If	End SubEnd Class

Forgive any syntax errors. My VB is a bit rusty.