Questions about cookies and sessions in ASP.net application

Question

I am writing an ASP.Net application that allows anonymous people to post prayers and others to comment on/confirm to pray for these objects. Prayers are stored in a SQL Server 2008 database with a unique identifier.

They are displayed using a repeater control and a hidden field to store the ID of the row. Each item in the repeater contains a button that allows anonymous people to pray and this is incremented as a counter inside the database.

Basically, once a user has confirmed that he/she is praying for this item, I want to disable the button and display the total count for that row.

It is my understanding that I can store data in cookies/sessions so the only solution I could come up with so far would be to store the ID of the row into one of these objects and then use custom logic inside of my repeater control to check to see which are present.

Can anyone offer some insight as to what the most efficient way to accomplish something like this might be? If there are options other than cookie or session I'd be glad to hear that too.

EDIT: I am trying to implement this solution using the following logic.

Codebehind:

protected bool IsPrayerInCookie(string prayerId)
    {
        if(Request.Cookies["prayers"][prayerId] != null)
        {
            return false;
        }
        else
        {
            return true;
        }
    }

ASPX:

 <span class="confirmed_prayers"><span class="trans">
                            <asp:Label runat="server" ID="lblConfirmedPrayers" Text='<%# Eval("ConfirmedPrayers") %>' />
                            people have prayed for this.</span></span>
                            <% if(!IsPrayerInCookie(Eval("PrayerId").ToString())) 
                                {   
                            %>
                                <asp:LinkButton ID="btnPray" CssClass="but_styled" runat="server" TabIndex="8" CommandName="IncrementPrayer">
                                <span><span class="check">
                                    Pray for This</span></span></asp:LinkButton>
                            <%
                                }
                            %>

This isn't working however. Can anyone help me figure out how to make the if statement work inside of the aspx file to properly call the code behind method with the correct ID?

Answer 1

Session will only last as long as the user is on the site. Therefore, if they close their browser and come back, it will be gone.

Cookies would be the better choice, and only if they clear their cookies will this data be gone.

If you don't require the user to log in, I'm thinking this is all you could do.

Heres the MSDN page on cookies:

http://msdn.microsoft.com/en-us/library/ms178194.aspx

For the actual cookie storage, I would do something like:

Response.Cookies["prayerlist"][CurrentPrayerItemID].Value = "something"; //All that matters is that they have the cookie with this ID.
Response.Cookies["prayerlist"].Expires = DateTime.MaxValue;

So when someone clicks to add that item, you will first want to check to see if they already have that id in their cookie, like so:

if(Response.Cookies["prayerlist"][CurrentPrayerItemID] != null)
{
    Response.Cookies["prayerlist"][CurrentPrayerItemID].value = "something";

    // Add prayer to Database
}

And likewise, you would check the cookie whenever you bind the repeater. If they have that cookie, you would disable the corresponding pray button.

I'm not sure how to approach this, since idk how your binding, but it will look something like this:

foreach(Item item in YourListOfItemsThatYouAreBindingToTheRepeater)
{
    if(Response.Cookies["prayerlist"][CurrentPrayerItemID] != null)
    {
        //Disable Button - Set "HasPrayed" = true
    }
}

To actually disable the button, what i would do is set a value in your list to false, and then in the aspx page, do something like this:

<asp:Button ID="button1" runat="server" Enabled='<%# !(bool)Eval("HasPrayed") %>' />

Using !(bool)Eval("HasPrayed") since you want to set enabled to false if HasPrayed is true.

Answer 2

You can use sessions to store the prayer items that the user has clicked on, but when they come back to your site it will forget all the previous items because the session has been lost.

In this case you can use a cookie to store all the prayer item ids that the user has clicked the "I'll pray for this" button. I'd go this route if you don't want to require user logins.

For the code you're describing, I think you could use an ASP.NET UpdatePanel which will allow you to update/show the number of people praying for the item and to disable the button.