Application wide variables

Dmitrij Jazel

Posted on 26/09/2012 19:27:32

Edit: Wops, wrong category... could someone please move this post to Developmet section?

Hej DW guys,

I have a question here,

Let's say I have some data, that must be available withing application. For example Application Variables could store some of it.

For example store a set that must be accessed really quick, and to take some load of the database I was thinking to put this Dictionary

I was trying to use something like this in DW:

Application["CachedValues"] = cachedList;
Dictionary<string, double> cachedList = (Dictionary<string, double>)Application["CachedValues"];

But it does not seem to work.

Dynamicweb.Cache Cache = new Dynamicweb.Cache();

This one either :-/

Any reason why? or maybe there are more suggestions how to achieve something like this?

P.S. I am full aware about application variables side-effect - that they can drain the memory on the server, so must be treated with caution.

But this variable I am working with, may not change for 24-48 hours (it must be constantly accessible globally), and if it does, I will change it directly, so it must be alive as long as application is alive. Just 1. It would help performance alot, as I could save additional connection to database and list through 1000 values.

Many thanks in advance! :-)

Regards,

Dmitrij

Replies

Imar Spaanjaars

Posted on 26/09/2012 20:03:23

Can you define "does not seem to work"? Your current code wouldn't compile because the order is incorrect, but assuming you have this in the right order in your code, I see no reason why this wouldn't work. This is standard ASP.NET and not really related to Dynamicweb.

Can you post your full code and a better problem description?

Cheers,

Imar

Dmitrij Jazel

Posted on 26/09/2012 20:30:38

Hej Imar,

Sure thing, this is how my CodeBehind file contains, when I create small webform application on my local machine:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace cacheLocalTest
{
    public partial class Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (Application["CachedValues"] == null)
            {
                Button1.Text = "!empty!";
            }
            else
            {
                Dictionary<string, double> prices = (Dictionary<string, double>)Application["CachedValues"];
                Dictionary<string, double> prices2 = (Dictionary<string, double>)Application["CachedValues"];
                Button1.Text = "!FULL!";

                foreach (KeyValuePair<string, double> pair in prices)
                {
                    Button1.Text = pair.Key + pair.Value.ToString();
                }
            }
        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            Dictionary<string, double> prices = new Dictionary<string, double>();
            prices.Add("First", 1.1);
            prices.Add("Second", 2.2);
            prices.Add("Third", 3.3);
            Application["CachedValues"] = prices;
        }
    }
}

And this one works fine. But when I am trying to use it in the example below - than it just gives me a red underline, compiler should suggest some import or something like that, or a reason why I can't use it. But I can't seem to find it.

Here is the code where I need to use it... here I am getting the error... Again - the error is just red underline with suggestion to use System.Net.Mime.MediaTypeNames.Application

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using System.Data.SqlClient;
using System.Web.Caching;

namespace IMPORT_SERVICE
{
    public class DBService
    {
		// other database service methods.....

        internal void reCache()
		{
            //1) load user names
            List<UserInfoHolder> userInfo = getAllUserInformation();
            List<string> allProductsIDs = getAllProductsIDs();

            foreach (UserInfoHolder u in userInfo)
            {
                Dynamicweb.Cache cacheTest = new Dynamicweb.Cache();
                string appMsg;
                appMsg = (string)(Application["Message"]);
				
                //Cache["Key1"] = ""; 
				/*Application["MyTest"] = "";*/
            }
			Dictionary<string,float> priceValues = new Dictionary<string,float>();	
				// Populate priceValues
            Application["prices"] = priceValues;

            //2) foreach username
				//2.1 filter discount table - call DB and compare prices on the fly.
		}
	}
}

I feel that I am doing something wrong here, but it seams so easy to actually use Application variables, just like Session state, but for some reason - just getting compiler error with suggestion to use System.Net.Mime.MediaTypeNames.Application - that is not something I need to use... I am using System.web reference, so it should be fine :-/

Regards,

Dmitrij

Imar Spaanjaars

Posted on 26/09/2012 20:47:49

This post has been marked as an answer

Application is made available as a property on ASPX pages, User Controls and Master Pages so you can use it directly. To use it in other classes such as class files inside a separae class library, you need to use HttpContext.Current.Application instead. Obviously, you can only use it when there is an actual HttpContext available.

Hope this helps,

Imar

Votes for this answer: 1

Dmitrij Jazel

Posted on 26/09/2012 21:03:13

Hej Imar,

That looks like it is working so far! :-)

I will let you know here if there are any other issues but I don't think that there will be any regarding this topic.

I must thank you again for lightning fast help! :-)))

Regards,

Dmitrij

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Application wide variables

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